JP7706580B2 - Refrigerant distributor, heat exchanger and refrigeration cycle device - Google Patents

Description

The present disclosure relates to a refrigerant distributor, a heat exchanger and a refrigeration cycle device.

An air conditioner is equipped with a refrigerant circuit that circulates a refrigerant. The refrigerant circuit includes a compressor that compresses the refrigerant, a throttling device that expands the refrigerant, an indoor heat exchanger that causes the refrigerant to exchange heat with indoor air, an outdoor heat exchanger that causes the refrigerant to exchange heat with outdoor air, and refrigerant piping that connects these in a ring shape. When the air conditioner is performing cooling operation, the indoor heat exchanger functions as an evaporator that absorbs heat from the outside and evaporates the refrigerant, and when the air conditioner is performing heating operation, the outdoor heat exchanger functions as an evaporator.

The refrigerant circulating through the refrigerant circuit is sent out in a two-phase gas-liquid state from the throttling device and flows into the evaporator, i.e., the indoor heat exchanger or outdoor heat exchanger, where it exchanges heat with the air as it flows through the heat transfer tubes built into the evaporator. When the two-phase refrigerant exchanges heat with the air, the liquid refrigerant contained in this refrigerant evaporates and changes to gas-phase refrigerant. As a result, the refrigerant changes from a two-phase gas-liquid state to a single-phase gas state while flowing through the heat transfer tube. In other words, the refrigerant flows in a two-phase gas-liquid state through a portion of the heat transfer tube, and in a single-phase gas state through the remaining section of the heat transfer tube.

When pressure loss of the refrigerant occurs inside the heat transfer tubes, the heat exchange efficiency of the evaporator decreases. For this reason, the indoor heat exchanger and outdoor heat exchanger that function as evaporators are equipped with multiple heat transfer tubes and a refrigerant distributor that distributes the refrigerant to these heat transfer tubes. By distributing the refrigerant to each heat transfer tube, the flow rate of the refrigerant inside each heat transfer tube is reduced, and the pressure loss of the refrigerant is reduced.

When the refrigerant piping inside the evaporator has a curved section located upstream of the refrigerant distributor, centrifugal force is applied when the refrigerant in a two-phase gas-liquid state passes through the curved section, and the liquid refrigerant contained in this refrigerant flows into the refrigerant distributor in a biased state. In this case, the amount of liquid refrigerant distributed to each heat transfer tube by the refrigerant distributor varies. The smaller the amount of liquid refrigerant distributed in a heat transfer tube, the longer the section in which the refrigerant flows in a single-phase gas phase. Since the heat transfer coefficient of a refrigerant in a single-phase gas phase is extremely small compared to the heat transfer coefficient of a refrigerant in a two-phase gas-liquid phase, the heat exchange efficiency in the section in which the refrigerant flows in a single-phase gas phase in the heat transfer tube is extremely low compared to the heat exchange efficiency in the section in which the refrigerant flows in a two-phase gas-liquid phase. For this reason, the longer the section in which the refrigerant flows in a single-phase gas phase, the lower the heat exchange efficiency. Therefore, if there is variation in the length of the section in which the refrigerant flows in a single-phase gas phase in each heat transfer tube, the heat exchange efficiency of the evaporator decreases.

In view of the above circumstances, the refrigerant distributor described in Patent Document 1 includes an inlet pipe into which a two-phase gas-liquid refrigerant flows, a branch space that mixes and branches the two-phase gas-liquid refrigerant that flows in from the inlet pipe, a plurality of outlet pipes from which the two-phase gas-liquid refrigerant branched in the branch space flows out, an inflow passage connecting the inlet pipe and the branch space, and a plurality of outlet passages respectively connecting the branch space and the plurality of outlet pipes. The branch space includes a mixing portion having a recessed shape formed at a position opposite to the inflow passage. If the inner diameter of the inflow passage is Da [mm], the flow path cross-sectional area of the inflow passage is Ai [mm ² ], the inner diameter of the mixing section is Db [ ^mm ], the area of the branch space is Av [mm ² ], the height of the branch space is Hv [mm], the area of the circumscribed circle of the outflow passage is Apo [mm 2 ], and the area of the inscribed circle of the outflow passage is Api [mm2], then Ai/(π×Da×Hv)≧0.5, Av/(Apo-Api)≦2.0, and Db/Da≦1.0. With this configuration, the refrigerant distributor described in Patent Document 1 reduces the variation in the amount of refrigerant sent from each outlet tube to the heat transfer tubes.

JP 2014-81149 A

However, the refrigerant distributor described in Patent Document 1 may not be able to reduce the variation in the amount of refrigerant distributed to each heat transfer tube, depending on the flow rate, type, and temperature of the refrigerant flowing into the refrigerant distributor.

The present disclosure has been made in consideration of the above-mentioned circumstances, and aims to reduce the variation in the amount of refrigerant distributed to each heat transfer tube when distributing refrigerant to multiple heat transfer tubes, regardless of the flow rate, type, and temperature of the refrigerant.

In order to achieve the above object, the refrigerant distributor according to the present disclosure includes a mixing section having a cylindrical shape. An inlet through which the refrigerant flows is formed at a first end of the mixing section. A plurality of outlets through which the refrigerant flows out is formed at a second end opposite to the first end of the mixing section. A recess facing the inlet is formed at the second end of the mixing section. The mixing section guides the gas-phase refrigerant contained in the refrigerant that flows from the inlet into the recess so that it collides with the liquid-phase refrigerant contained in the refrigerant that flows from the inlet, thereby pressing the liquid-phase refrigerant against the first end of the mixing section, guiding the liquid-phase refrigerant to flow along the first end of the mixing section and the side wall of the mixing section, diffusing the liquid-phase refrigerant in the circumferential direction of the second end, and then sending it out from the outlet. The refrigerant distributor further includes a guide section disposed at the second end of the mixing section. The guide section guides the gas-phase refrigerant that is guided to the mixing section and collides with the liquid-phase refrigerant from the second end of the mixing section to the first end of the mixing section.

According to the above configuration, the variation in the amount of refrigerant discharged from each outlet is reduced, regardless of the flow rate, type, and temperature of the gas-liquid two-phase refrigerant that has flowed into the mixing section. As a result, when a heat transfer tube is connected to each outlet, the variation in the amount of refrigerant flowing into the heat transfer tube from each outlet is reduced, regardless of the flow rate, type, and temperature of the refrigerant. In other words, according to the above configuration, when distributing refrigerant to multiple heat transfer tubes, the variation in the amount of refrigerant distributed to each heat transfer tube can be reduced, regardless of the flow rate, type, and temperature of the refrigerant.

Refrigerant circuit diagram of an air conditioner according to embodiment 1 of the present disclosure Mollier diagram showing the state of refrigerant circulating in the refrigerant circuit according to the first embodiment of the present disclosure. FIG. 1 is a diagram showing the configuration of an indoor heat exchanger and an outdoor heat exchanger according to a first embodiment of the present disclosure; FIG. 1A is a perspective view of a refrigerant distributor and internal refrigerant piping according to a first embodiment of the present disclosure; FIG. 1B is a cross-sectional view of the internal refrigerant piping according to the first embodiment of the present disclosure. FIG. 1A is a perspective view of a refrigerant distributor according to a first embodiment of the present disclosure; FIG. 1B is a plan view of the refrigerant distributor according to the first embodiment of the present disclosure; VI-VI line cross-sectional view of the refrigerant distributor according to the first embodiment of the present disclosure in FIG. FIG. 13 is a diagram showing the relationship between the height of the mixing section and the liquid-phase refrigerant distribution rate of the reference outlet pipe according to the first embodiment of the present disclosure. FIG. 2 is a schematic diagram illustrating an example of a refrigerant flow inside a refrigerant distributor according to the first embodiment of the present disclosure. (A) A schematic diagram showing an example of a refrigerant flow inside the refrigerant distributor according to the first embodiment of the present disclosure in a case where the liquid-phase refrigerant distribution rate of the reference outlet pipe is suppressed. (B) A schematic diagram showing an example of a refrigerant flow inside the refrigerant distributor according to the first embodiment of the present disclosure in a case where the liquid-phase refrigerant distribution rate of the reference outlet pipe is not suppressed because the height of the mixing section is too small. (C) A schematic diagram showing an example of a refrigerant flow inside the refrigerant distributor according to the first embodiment of the present disclosure in a case where the liquid-phase refrigerant distribution rate of the reference outlet pipe is not suppressed because the height of the mixing section is too large. FIG. 1 is a diagram showing a relationship between the mass flow rate of a refrigerant and a liquid-phase refrigerant distribution ratio of a reference outlet pipe according to the first embodiment of the present disclosure. FIG. 13 is a diagram showing the relationship between the height of the mixing section and the liquid-phase refrigerant distribution rate of the reference outlet pipe according to the first embodiment of the present disclosure. FIG. 13 is a diagram showing the relationship between the height of a mixing section and the pressure loss of a refrigerant according to the second embodiment of the present disclosure. FIG. 13 is a diagram showing a range of heights of a mixer according to a modification of the second embodiment of the present disclosure. 14A is a plan view of a refrigerant distributor according to a third embodiment of the present disclosure; FIG. 14B is a cross-sectional view of the refrigerant distributor according to the third embodiment of the present disclosure taken along line A-A in FIG. 14A; FIG. 13 is a schematic diagram showing an example of a refrigerant flow inside a refrigerant distributor according to a third embodiment of the present disclosure. FIG. 13 is a vertical cross-sectional view of a refrigerant distributor according to a modification of the third embodiment of the present disclosure.

Hereinafter, the refrigerant distributor, heat exchanger, and refrigeration cycle device according to the embodiment of the present disclosure will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals.

(Embodiment 1)
The air conditioner 100 shown in Fig. 1 conditions the air in a space to be air-conditioned, such as an indoor space or the interior space of an automobile. The air conditioner 100 is an example of a refrigeration cycle device. The air conditioner 100 includes a refrigerant circuit 10 that circulates a refrigerant, and a control device 20 that controls the operation of the refrigerant circuit 10.

The refrigerant circuit 10 includes a compressor 1 that compresses the refrigerant, a throttling device 2 that expands the refrigerant and switches the circulation direction of the refrigerant inside the refrigerant circuit 10, an indoor heat exchanger 3 that is built into an indoor unit 6 installed inside the space to be air-conditioned and causes the refrigerant to exchange heat with the air inside the space to be air-conditioned, an outdoor heat exchanger 4 that is built into an outdoor unit 7 installed outside the space to be air-conditioned and causes the refrigerant to exchange heat with the air outside the space to be air-conditioned, and a main refrigerant piping 5 through which the refrigerant flows, connecting the compressor 1 to the outdoor heat exchanger 4 in a ring shape. The indoor heat exchanger 3 and the outdoor heat exchanger 4 are examples of heat exchangers.

The control device 20 includes a processor that executes various processes and a memory that stores data and programs. The processor of the control device 20 functions as an operation control unit that controls the operation of the refrigerant circuit 10 by executing the programs stored in the memory, and controls the operation of the compressor 1, the throttling device 2, the indoor unit 6, and the outdoor unit 7 by transmitting control signals.

The throttling device 2 is equipped with an expansion valve that expands the refrigerant and a four-way valve that switches the refrigerant circulation direction. The control device 20 controls the four-way valve of the throttling device 2 to switch the refrigerant circulation direction, thereby switching the operating state of the air conditioner 100 between a cooling operation state and a heating operation state. When the air conditioner 100 is in a cooling operation state, the four-way valve circulates the refrigerant in the direction indicated by the arrow JJ in FIG. 1. As a result, the indoor heat exchanger 3 functions as an evaporator that absorbs heat from the outside and evaporates the refrigerant, and the outdoor heat exchanger 4 functions as a condenser that releases heat to the outside and condenses the refrigerant, thereby cooling the air inside the air-conditioned space. When the air conditioner 100 is in a heating operation state, the four-way valve circulates the refrigerant in the direction indicated by the arrow KK in FIG. 1. As a result, the indoor heat exchanger 3 functions as a condenser and the outdoor heat exchanger 4 functions as an evaporator, and the air inside the air-conditioned space is heated.

Figure 2 is a Mollier diagram showing the state of the refrigerant circulating through the refrigerant circuit 10. In Figure 2, the horizontal axis represents the enthalpy of the refrigerant, and the vertical axis represents the pressure of the refrigerant. Figure 2 shows the saturated liquid line MM and the saturated vapor line NN. The region where the refrigerant enthalpy H is smaller than the saturated liquid line MM is the region where the refrigerant is in a single-phase liquid state, and the region where the refrigerant enthalpy H is larger than the saturated vapor line NN is the region where the refrigerant is in a single-phase gas state. The region where the refrigerant enthalpy H is above the saturated liquid line MM and below the saturated vapor line NN is the region where the refrigerant is in a two-phase gas-liquid state.

In the cooling operation state, the refrigerant is first compressed by the compressor 1, and as shown in the path from point S to point T in FIG. 2, the refrigerant changes from a low-pressure gas-phase refrigerant to a high-pressure gas-phase refrigerant, and flows into the outdoor heat exchanger 4. The refrigerant that flows into the outdoor heat exchanger 4 exchanges heat with the air outside the space to be air-conditioned, dissipates heat, is condensed, and becomes a high-pressure liquid-phase refrigerant, as shown in the path from point T to point U in FIG. 2, and flows into the throttling device 2. The refrigerant is then reduced in pressure by being expanded by the expansion valve provided in the throttling device 2, and becomes a low-pressure gas-liquid two-phase refrigerant, as shown in the path from point U to point V in FIG. 2, and flows into the indoor heat exchanger 3. The refrigerant that flows into the indoor heat exchanger 3 exchanges heat with the air inside the space to be air-conditioned, absorbs heat, evaporates, and becomes a low-pressure gas-phase refrigerant, as shown in the path from point V to point S in FIG. 2, and flows into the compressor 1.

The indoor unit 6 comprises a housing that houses the indoor heat exchanger 3, a fan that flows air through the indoor heat exchanger 3, and a motor that drives the fan according to control by the control device 20. The fan is driven to rotate by the motor, and causes air inside the space to be air-conditioned to flow into the inside of the housing. The indoor heat exchanger 3 causes the refrigerant to exchange heat with the air that has flowed into the inside of the housing. The fan is driven to rotate by the motor, and sends the air that has exchanged heat with the refrigerant into the space to be air-conditioned. This conditions the air inside the space to be air-conditioned.

The outdoor unit 7 comprises a housing that houses the outdoor heat exchanger 4, a fan that flows air through the outdoor heat exchanger 4, and a motor that drives the fan under control of the control device 20. The fan is driven to rotate by the motor, and causes air outside the space to be air-conditioned to flow into the inside of the housing. The outdoor heat exchanger 4 causes the refrigerant to exchange heat with the air that has flowed into the inside of the housing. The fan is driven to rotate by the motor, and sends the air that has exchanged heat with the refrigerant to the outside of the space to be air-conditioned.

The indoor heat exchanger 3 has the same configuration as the outdoor heat exchanger 4. As shown in FIG. 3, the indoor heat exchanger 3 and the outdoor heat exchanger 4 are provided with eight heat transfer tubes 30, a pair of refrigerant distributors 31 connected to both ends of each heat transfer tube 30 to distribute the refrigerant to each heat transfer tube 30, and a pair of internal refrigerant pipes 32 connecting each refrigerant distributor 31 to the main refrigerant pipe 5. The refrigerant distributor 31 is disposed at the inlet of the indoor heat exchanger 3 and the outdoor heat exchanger 4. Specifically, one of the pair of refrigerant distributors 31 is connected to the compressor 1 via the main refrigerant pipe 5 and the internal refrigerant pipe 32, and the other is connected to the throttling device 2 via the main refrigerant pipe 5 and the internal refrigerant pipe 32. The refrigerant sent from the compressor 1 or the throttling device 2 flows into the refrigerant distributor 31 via the main refrigerant pipe 5 and the internal refrigerant pipe 32, and is distributed to each heat transfer tube 30 by the refrigerant distributor 31. Each heat transfer tube 30 is connected to a plurality of heat dissipation fins, and the refrigerant distributed to each heat transfer tube 30 by the refrigerant distributor 31 exchanges heat with the air via the heat dissipation fins while flowing through each heat transfer tube 30.

When the indoor heat exchanger 3 and the outdoor heat exchanger 4 function as evaporators, the refrigerant in a two-phase gas-liquid state sent from the throttling device 2 flows into the refrigerant distributor 31 connected to the throttling device 2, is distributed to each heat transfer tube 30 by the refrigerant distributor 31, and exchanges heat with the air while flowing through each heat transfer tube 30. By distributing the refrigerant to multiple heat transfer tubes 30, the flow rate of the refrigerant flowing through each heat transfer tube 30 is reduced, the pressure loss of the refrigerant is reduced, and the heat exchange efficiency of the indoor heat exchanger 3 and the outdoor heat exchanger 4, which are evaporators, is improved. When the refrigerant in a two-phase gas-liquid state exchanges heat with air, the liquid phase refrigerant contained in this refrigerant evaporates and changes to a gas phase refrigerant. As a result, the refrigerant changes from a two-phase gas-liquid state to a single-phase gas phase state with an extremely small heat transfer coefficient while flowing through the heat transfer tube. The refrigerant flowing through each heat transfer tube 30 changes to a single-phase gas state, and then joins together in a refrigerant distributor 31 connected to the compressor 1 , and is sent from this refrigerant distributor 31 to the compressor 1 .

The heat exchange efficiency of the evaporator can be improved by reducing the variation in the length of the section in which the refrigerant flows in a single-phase gas state in each heat transfer tube 30, i.e., the section in which the heat exchange efficiency is low. The variation in the length of the section in which the refrigerant flows in a single-phase gas state can be reduced by reducing the variation in the thermal load of the refrigerant in each heat transfer tube 30. The thermal load of the refrigerant in the heat transfer tube 30 is equal to the product of the mass flow rate of the refrigerant flowing through the heat transfer tube 30 and the difference between the enthalpy of the refrigerant at the inlet and the enthalpy of the refrigerant at the outlet of the heat transfer tube 30. Therefore, the variation in the thermal load of the refrigerant in each heat transfer tube 30 can be reduced by reducing the variation in the mass flow rate of the refrigerant flowing through each heat transfer tube 30. The refrigerant distributor 31 of this embodiment reduces the variation in the mass flow rate of the refrigerant flowing through each heat transfer tube 30, thereby reducing the variation in the thermal load of the refrigerant in each heat transfer tube 30 and reducing the variation in the length of the section in each heat transfer tube 30 where the refrigerant flows in a single-phase gas state, thereby improving the heat exchange efficiency of the evaporator.

Figure 4 (A) is a perspective view of the internal refrigerant piping 32 connected to the throttling device 2 via the main refrigerant piping 5 and the refrigerant distributor 31 connected to the internal refrigerant piping 32. The internal refrigerant piping 32 is connected to the main refrigerant piping 5 and has a straight-lined connection section 39, a U-shaped curved section 40 located downstream of the connection section 39, and a straight-lined straight section 41 located downstream of the curved section 40. The downstream end of the straight section 41 is connected to the refrigerant distributor 31. The refrigerant in a gas-liquid two-phase state that flows into the internal refrigerant piping 32 from the throttling device 2 via the main refrigerant piping 5 passes through the connection section 39, the curved section 40, and the straight section 41 in this order, and flows into the refrigerant distributor 31. Figure 4 (B) is a cross-sectional view of the internal refrigerant piping 32 cut along a cut surface perpendicular to the extension direction of the connection section 39 and the straight section 41. For ease of understanding, an XYZ orthogonal coordinate system is set as shown in Figures 4(A) and 4(B). The Z axis is set parallel to the direction of gravity g. The X axis is set perpendicular to the Z axis and parallel to a straight line TL passing through the axis 39a of the connection portion 39 and the axis 41a of the straight pipe portion 41. The Y axis is set perpendicular to the X axis and the Z axis.

When the refrigerant in a gas-liquid two-phase state flows through the internal refrigerant piping 32, the gas phase refrigerant contained in this refrigerant flows through the center of the internal refrigerant piping 32, and the liquid phase refrigerant contained in this refrigerant flows along the inner wall of the internal refrigerant piping 32 in a liquid film state. However, because there is a difference between the density of the gas phase refrigerant and the density of the liquid phase refrigerant, there is a difference between the flow speed of the gas phase refrigerant and the flow speed of the liquid phase refrigerant. As a result, shear stress acts on the liquid phase refrigerant in a liquid film state at the interface between the gas phase refrigerant and the liquid phase refrigerant, causing droplets to break off from the liquid film and scatter. For this reason, in the center of the internal refrigerant piping 32, there is a large amount of liquid phase refrigerant in a liquid droplet state along with the gas phase refrigerant.

When the gas-liquid two-phase refrigerant flows through the curved section 40, centrifugal force is applied to the refrigerant, and the liquid-phase refrigerant contained in the refrigerant is biased in the direction of this centrifugal force. In other words, the thickness of the liquid film of the liquid-phase refrigerant adhering to the inner wall of the internal refrigerant piping 32 becomes uneven. As a result, the refrigerant that has passed through the curved section 40 flows into the straight pipe section 41 with the liquid-phase refrigerant contained in the refrigerant biased in the +X-axis direction.

When the refrigerant flows through the straight pipe section 41, a secondary flow occurs that makes the thickness of the liquid film of the liquid phase refrigerant adhering to the inner wall uniform, and the bias of the liquid phase refrigerant is reduced. If the straight pipe section 41 is sufficiently long, the bias of the liquid phase refrigerant is eliminated while the refrigerant flows through the straight pipe section 41, and the refrigerant flows into the refrigerant distributor 31 without any bias in the liquid phase refrigerant. However, in this embodiment, due to structural constraints, the straight pipe section 41 is shorter than the length necessary to eliminate the bias in the liquid phase refrigerant. Therefore, the refrigerant flows into the refrigerant distributor 31 with the liquid phase refrigerant biased in the +X axis direction.

As shown in FIG. 5(A), the refrigerant distributor 31 includes an inlet pipe 50 connected to the internal refrigerant piping 32, a mixing section 51 connected to the inlet pipe 50, a plurality of outlet pipes 52 connected to the mixing section 51, and a recessed section 53 connected to the mixing section 51.

The upstream end of the inlet pipe 50 is connected to the straight pipe section 41 of the internal refrigerant piping 32, and the downstream end of the inlet pipe 50 is connected to the inlet 510 formed at the upstream end section 51a of the mixing section 51. In other words, the internal refrigerant piping 32 is connected to the inlet 510 via the inlet pipe 50. The upstream end section 51a of the mixing section 51 is an example of the first end section. The inner diameter of the inlet pipe 50 is equal to the inner diameter of the inlet 510 and the inner diameter of the straight pipe section 41 of the internal refrigerant piping 32. The refrigerant in a gas-liquid two-phase state discharged from the throttling device 2 flows into the inlet pipe 50 via the main refrigerant piping 5 and the internal refrigerant piping 32. The refrigerant that flows into the inlet pipe 50 from the internal refrigerant piping 32 flows into the mixing section 51 from the inlet pipe 50 via the inlet 510.

The mixing section 51 is hollow and has a cylindrical shape. The outlet pipe 52 and the recessed section 53 are connected to the downstream end 51b of the mixing section 51. The downstream end 51b of the mixing section 51 is the end opposite to the upstream end 51a and is an example of the second end. The refrigerant distributor 31 has eight outlet pipes 52, the same as the number of heat transfer tubes 30, and these outlet pipes 52 are connected to the above-mentioned eight heat transfer tubes 30. Each outlet pipe 52 is connected to a different heat transfer tube 30. Specifically, the downstream end of each outlet pipe 52 is connected to the heat transfer tube 30. The upstream end of each outlet pipe 52 is connected to one of a plurality of outlets 511 formed at the downstream end 51b of the mixing section 51. In other words, each heat transfer tube 30 is connected to each outlet 511 via each outlet pipe 52. The refrigerant that flows into the mixing section 51 from the inlet pipe 50 is sent from the mixing section 51 to each outlet pipe 52 via each outlet port 511. That is, the refrigerant that flows into the mixing section 51 is distributed to each outlet pipe 52. The refrigerant that flows into each outlet pipe 52 from the mixing section 51 is sent from each outlet pipe 52 to the heat transfer tubes 30 connected to each outlet pipe 52. As a result, the refrigerant in a gas-liquid two-phase state that flows into the refrigerant distributor 31 is distributed to each heat transfer tube 30.

The space inside the recess 53 corresponds to the recess formed in the mixing section 51. The recess 53 is connected to the mixing section 51 through a circular opening 51c formed at the downstream end 51b of the mixing section 51, facing the inlet pipe 50 and the inlet 510. That is, the space inside the recess 53, which is a recess in the mixing section 51, is formed at the downstream end 51b of the mixing section 51, facing the inlet pipe 50 and the inlet 510. The recess 53 has a shape in which a hollow cone is connected to a cylinder connected to the opening 51c of the mixing section 51. A part of the refrigerant sent from the inlet 510 flows into the internal space of the recess 53, and then flows from the recess 53 into the mixing section 51.

As described above, the refrigerant in the gas-liquid two-phase state flows into the refrigerant distributor 31 with the liquid refrigerant contained therein biased in the +X-axis direction. For this reason, if no measures are taken, the amount of liquid refrigerant discharged from each outlet 511 of the refrigerant distributor 31 through each outlet pipe 52 will vary. Specifically, as shown in FIG. 5B, the positions of each outlet pipe 52 are different from each other in the X-axis direction, and if no measures are taken, the amount of liquid refrigerant discharged from the outlet pipe 52 with a larger X-coordinate will be greater if no measures are taken. Hereinafter, the outlet pipe 52 with the largest X-coordinate, which is the outlet pipe 52 with the largest amount of liquid refrigerant discharged if no measures are taken, will be referred to as the "reference outlet pipe 52a" and distinguished from the other outlet pipes 52. However, if there is no need to distinguish between the reference outlet pipe 52a and the other outlet pipes 52, they will be collectively referred to simply as the "outlet pipe 52".

In this embodiment, assuming that the inner diameter of the inlet 510 shown in FIG. 6 is Di [mm], the mass flow rate of the refrigerant in a gas-liquid two-phase state flowing from the internal refrigerant piping 32 to the inlet pipe 50 is G [kg/h], the gas phase density of this refrigerant is ρ _g [kg/m ³ ], and the liquid phase density of this refrigerant is ρ _l [kg/m ³ ], the height h [mm] of the mixing section 51 satisfies the following formula 1. FIG. 6 is a cross-sectional view of the refrigerant distributor 31 cut along the line VI-VI shown in FIG. 5 (B). The height h of the mixing section 51 is the distance between the upstream end 51a and the downstream end 51b of the mixing section 51 in the internal space of the mixing section 51. The gas phase density ρ _g of the refrigerant in a gas-liquid two-phase state is the density of the gas phase refrigerant contained in this refrigerant, and the liquid phase density ρ _l of this refrigerant is the density of the liquid phase refrigerant contained in this refrigerant. More specifically, in this embodiment, the height h of the mixing section 51 is 2.5 mm or more and 4 mm or less. As will be described later, this configuration can reduce the variation in the amount of refrigerant discharged from each outlet 511 through each outlet pipe 52, regardless of the flow rate, type, and temperature of the refrigerant in a gas-liquid two-phase state that has flowed into the inlet pipe 50.

In addition, in this embodiment, the diameter Dc [mm] of the recess formed in the mixing section 51, which is the space inside the recess 53, is larger than the inner diameter Di of the inlet 510. The diameter Dc of the recess formed in the mixing section 51 is equal to the diameter of the opening 51c formed in the mixing section 51 to which the recess 53 is connected. As will be described later, this configuration can reduce the variation in the amount of refrigerant discharged from each outlet 511 through each outlet pipe 52.

In addition, in this embodiment, the first distance Li [mm], which is the distance between the recess formed in the mixing section 51 and the axis QQ of the outlet 511, is greater than the second distance Lo [mm], which is the distance between the axis QQ of the outlet 511 and the side wall 51d of the mixing section 51. The axis QQ of each outlet 511 is the same as the axis of the outlet pipe 52 connected to each outlet 511. In this embodiment, as shown in FIG. 5 (B), the downstream end 51b of the mixing section 51 is circular, and each outlet 511 and each outlet pipe 52 are arranged away from the recess 53 to the radial outside of the downstream end 51b of the mixing section 51. Specifically, the eight outlet pipes 52 and the outlet 511 to which each outlet pipe 52 is connected are arranged on the circumference of one circle centered on the axis of the recess 53. In addition, the axis of the mixing section 51 is the same as the axis of the recess. Therefore, the distance between the axis QQ of each outlet 511 and the recess is the same, and the distance between the axis QQ of each outlet 511 and the side wall 51d of the mixer 51 is the same. That is, the first distance Li and the second distance Lo of each outlet 511 are the same.

According to such a configuration, the processing when manufacturing the refrigerant distributor 31 can be made easy, and the manufacturing cost can be reduced. Specifically, when the material of the refrigerant distributor 31 is a metal material such as copper or aluminum, the recess of the mixing section 51 is formed by cutting the metal material with a drill. At this time, the shorter the distance between the outlet 511 and the recess of the mixing section 51, the less the amount of metal material present between the outlet 511 and the recess of the mixing section 51, making processing difficult and increasing the manufacturing cost. In this embodiment, the first distance Li is greater than the second distance Lo, so that the distance between the outlet 511 and the recess of the mixing section 51 is sufficiently large, making processing easy and reducing the manufacturing cost. The material of the refrigerant distributor 31 is not limited to a metal material, and may be any material such as resin. In addition, the manufacturing method of the refrigerant distributor 31 is not limited to the above-mentioned method, and may be any method such as press molding or integral molding.

The distribution of refrigerant by the refrigerant distributor 31 will be described below using the results of a computer-based simulation of the flow of refrigerant inside the refrigerant distributor 31. In this simulation, a gas-liquid two-phase refrigerant flows into the inlet pipe 50 with the liquid refrigerant contained in this refrigerant biased toward the +X axis. This simulation was performed under the following conditions: diameter Dc of the recess in the mixing section 51 = 7 mm, inner diameter Di of the inlet 510 = 6 mm, first distance Li = 8.5 mm, second distance Lo = 2.5 mm. In the simulation, R290, i.e., propane, was used as the refrigerant unless otherwise specified. The temperature of the refrigerant in the simulation is 10°C.

7 shows the relationship between the height h of the mixing section 51 and the liquid-phase refrigerant distribution rate of the reference outlet pipe 52a when the mass flow rate G of the refrigerant flowing into the inlet pipe 50 is 50 [kg/h], 100 [kg/h], 150 [kg/h], or 200 [kg/h], as determined by simulation. The liquid-phase refrigerant distribution rate of the reference outlet pipe 52a is the ratio of the mass flow rate of the liquid-phase refrigerant discharged through the reference outlet pipe 52a from the outlet 511 to which the reference outlet pipe 52a is connected to the sum of the mass flow rates of the liquid-phase refrigerant discharged through each outlet pipe 52 from each outlet 511. When the liquid phase refrigerant distribution ratio of the reference outlet pipe 52a, which has the largest amount of liquid phase refrigerant discharged among the eight outlet pipes 52 if no countermeasures are taken, becomes smaller, the liquid phase refrigerant distribution ratios of the other outlet pipes 52 arranged away from the reference outlet pipe 52a in the -X-axis direction opposite to the direction of the liquid phase refrigerant bias become larger, and the variation in the amount of refrigerant discharged from each outlet 511 becomes smaller.

7, the broken line showing the relationship between the height h of the mixing section 51 and the liquid-phase refrigerant distribution rate of the reference outlet pipe 52a has a downward convex shape regardless of the value of the refrigerant mass flow rate G. As is clear from this, the liquid-phase refrigerant distribution rate of the reference outlet pipe 52a becomes a minimum value when the height h of the mixing section 51 is a specific value, and becomes greater than the minimum value both when the height h is smaller than the specific value and when it is larger than the specific value. Therefore, by setting the height h of the mixing section 51 to an appropriate value, it is possible to reduce the liquid-phase refrigerant distribution rate of the reference outlet pipe 52a and reduce the variation in the amount of refrigerant discharged from each outlet 511.

Figure 8 shows an example of the flow of refrigerant inside the refrigerant distributor 31 when the refrigerant in a gas-liquid two-phase state flows into the refrigerant distributor 31 with the liquid-phase refrigerant CC contained in the refrigerant biased in the +X-axis direction. Figure 8 shows a vertical cross section of the refrigerant distributor 31 cut along a cut surface that includes the axis of the inlet pipe 50 and is perpendicular to the Y-axis direction. In Figure 8, arrows AA indicate the flow of the liquid-phase refrigerant CC contained in the refrigerant, and arrows BB indicate the flow of the gas-phase refrigerant contained in the refrigerant. As shown by arrow BB, the gas-phase refrigerant flows through the center of the inlet pipe 50, flows into the recess 53 after being sent out from the inlet 510, collides with the inner wall of the recess 53, and diffuses in the circumferential direction of the opening 51c of the mixing section 51. The gas-phase refrigerant then flows along the inner wall of the recess 53 and flows into the mixing section 51. The gas-phase refrigerant that has flowed into the mixing section 51 flows in a liquid film state along the inner wall of the inlet pipe 50 and collides inside the mixing section 51 with the liquid-phase refrigerant CC that has flowed into the mixing section 51 from the inlet 510. After colliding with the liquid-phase refrigerant CC, the gas-phase refrigerant flows along the downstream end 51b of the mixing section 51 toward the side wall 51d of the mixing section 51.

9(A) to 9(C) show longitudinal cross-sections of the refrigerant distributor 31 cut along a plane that includes the axis of the inlet pipe 50 and is perpendicular to the Y-axis direction. FIG. 9(A) shows an example of the flow of refrigerant inside the refrigerant distributor 31 when the liquid-phase refrigerant distribution rate of the reference outlet pipe 52a is suppressed. In the example of FIG. 9(A), the gas phase refrigerant collides with the liquid phase refrigerant CC inside the mixing section 51, so that the liquid phase refrigerant CC is pressed against the upstream end 51a of the mixing section 51. The pressed liquid phase refrigerant CC flows along the upstream end 51a as shown by the arrow AA, reaches the side wall 51d of the mixing section 51, and then flows along the side wall 51d to reach the downstream end 51b of the mixing section 51, and is sent from the outlet 511 to the reference outlet pipe 52a. The liquid-phase refrigerant CC diffuses in the circumferential direction of the downstream end 51b of the mixing section 51 while flowing along the upstream end 51a and the side wall 51d of the mixing section 51. As a result, a portion of the liquid-phase refrigerant CC that has flowed into the mixing section 51 while being biased in the +X-axis direction moves in the -X-axis direction, the liquid-phase refrigerant distribution ratio of the reference outlet pipe 52a becomes smaller, and the variation in the amount of the liquid-phase refrigerant CC discharged from each outlet 511 becomes smaller.

9(B) shows an example of the flow of refrigerant inside the refrigerant distributor 31 when the liquid-phase refrigerant distribution rate of the reference outlet pipe 52a is not suppressed because the height h of the mixing section 51 is too small. In the example of FIG. 9(B), the proportion of the liquid-phase refrigerant CC in the space inside the mixing section 51 is higher than in the example of FIG. 9(A). Therefore, in the example of FIG. 9(B), the flow rate of the gas-phase refrigerant that collides with the liquid-phase refrigerant CC inside the mixing section 51 and then flows toward the side wall 51d of the mixing section 51 is smaller than in the example of FIG. 9(A), and the gas-phase refrigerant that flows toward the side wall 51d of the mixing section 51 flows along the downstream end 51b of the mixing section 51 as shown by the arrow BB, and then bends in the direction of flowing into the reference outlet pipe 52a. As a result, a portion of the liquid phase refrigerant CC flowing in from the inlet 510 is dragged by the gas phase refrigerant bent in the direction flowing into the reference outlet pipe 52a, and flows directly into the reference outlet pipe 52a without flowing along the upstream end 51a and side wall 51d of the mixing section 51.

9(C) shows an example of the flow of refrigerant inside the refrigerant distributor 31 in the case where the liquid-phase refrigerant distribution rate of the reference outlet pipe 52a is not suppressed due to the height h of the mixing section 51 being too large. In the example of FIG. 9(C), the amount of gas-phase refrigerant that flows from the inlet 510 and flows toward the side wall 51d of the mixing section 51 without flowing into the recessed section 53 is larger than that in the example of FIG. 9(A). Therefore, the force applied from the gas-phase refrigerant to the liquid-phase refrigerant CC, which presses the liquid-phase refrigerant CC against the upstream end 51a of the mixing section 51, is smaller than that in the example of FIG. 9(A). As a result, the liquid-phase refrigerant CC flows directly into the reference outlet pipe 52a after flowing into the mixing section 51 from the inlet 510, without flowing along the upstream end 51a and side wall 51d of the mixing section 51, as shown in FIG. 9(C).

9(B) and 9(C), the liquid-phase refrigerant CC flowing in from the inlet 510 flows directly into the reference outlet pipe 52a, so the liquid-phase refrigerant CC does not diffuse in the circumferential direction of the downstream end 51b of the mixing section 51 before being discharged from the outlet 511 to the reference outlet pipe 52a, and the liquid-phase refrigerant distribution rate of the reference outlet pipe 52a is not suppressed, and the variation in the amount of liquid-phase refrigerant CC discharged from each outlet 511 is not suppressed. In contrast, in the example of FIG. 9(A), the liquid-phase refrigerant CC is suppressed from flowing directly into the reference outlet pipe 52a, the liquid-phase refrigerant distribution rate of the reference outlet pipe 52a is suppressed, and the variation in the amount of liquid-phase refrigerant CC discharged from each outlet 511 is suppressed.

When the height h of the mixing section 51 is a value at which the liquid-phase refrigerant CC flows directly into the reference outlet pipe 52a, not only when centrifugal force is applied to the refrigerant at the curved section 40 of the internal refrigerant piping 32, but also when gravity acts on the refrigerant in a direction that is not parallel to the direction of the refrigerant flow, the amount of liquid-phase refrigerant CC discharged from each outlet 511 varies. Specifically, when the axis of the inlet pipe 50 is inclined with respect to the gravity direction g, gravity is applied to the refrigerant flowing inside the inlet pipe 50 in a direction that is not parallel to the direction of the refrigerant flow, and the liquid-phase refrigerant CC contained in the refrigerant is biased. When the liquid-phase refrigerant CC flows into the mixing section 51 from the inlet 510 in a biased state due to the action of gravity, if the liquid-phase refrigerant CC flows directly into the reference outlet pipe 52a, the amount of liquid-phase refrigerant CC discharged from each outlet 511 varies. By preventing the liquid phase refrigerant CC from flowing directly into the reference outlet pipe 52a, the variation in the amount of liquid phase refrigerant CC discharged from each outlet 511 caused by the inclination of the axis of the inlet pipe 50 relative to the gravity direction g is reduced.

When the refrigerant distributor 31 is disposed inside the indoor heat exchanger 3 or the outdoor heat exchanger 4, if the refrigerant distributor 31 is installed so that the axis of the inlet pipe 50 is parallel to the direction of gravity g, the liquid phase refrigerant CC will not be biased due to the action of gravity as described above. However, in reality, it is difficult to install the refrigerant distributor 31 so that the axis of the inlet pipe 50 is completely parallel to the direction of gravity g, and the refrigerant distributor 31 is usually installed with the axis of the inlet pipe 50 slightly tilted with respect to the direction of gravity g.

Returning to FIG. 8, when the diameter Dc of the depression of the mixing section 51, which is the space inside the depression 53, is smaller than the inner diameter Di of the inlet 510, the area where the gas phase refrigerant flowing into the mixing section 51 from the depression 53 comes into contact with the liquid phase refrigerant CC flowing into the mixing section 51 from the inlet 510 is small. As a result, the force with which the gas phase refrigerant presses the liquid phase refrigerant CC against the upstream end 51a of the mixing section 51 is small, and the liquid phase refrigerant CC easily flows directly into the reference outlet pipe 52a. In this embodiment, the diameter Dc of the depression of the mixing section 51 is configured to be larger than the inner diameter Di of the inlet 510. According to this configuration, the area where the gas phase refrigerant flowing into the mixing section 51 from the depression 53 comes into contact with the liquid phase refrigerant CC flowing into the mixing section 51 from the inlet 510 is large, and the force with which the gas phase refrigerant presses the liquid phase refrigerant CC against the upstream end 51a of the mixing section 51 is large. This prevents the liquid phase refrigerant CC from flowing directly into the reference outlet pipe 52a, suppresses the liquid phase refrigerant distribution rate of the reference outlet pipe 52a, and reduces the variation in the amount of liquid phase refrigerant CC discharged from each outlet 511.

Figure 10 shows the relationship between the mass flow rate G of the refrigerant in a gas-liquid two-phase state flowing from the internal refrigerant piping 32 into the inlet pipe 50 and the liquid-phase refrigerant distribution rate of the reference outlet pipe 52a when the height h of the mixing section 51 is 2 [mm], 3 [mm], 4 [mm] or 5 [mm], obtained by simulation. As shown in Figure 10, regardless of the height h of the mixing section 51, the larger the mass flow rate G of the refrigerant, the smaller the liquid-phase refrigerant distribution rate of the reference outlet pipe 52a. The larger the mass flow rate G of the refrigerant, the larger the difference between the velocity of the gas-phase refrigerant contained in the refrigerant and the velocity of the liquid-phase refrigerant CC, and the larger the difference between the dynamic pressure of the gas-phase refrigerant and the dynamic pressure of the liquid-phase refrigerant CC. The greater the difference between the dynamic pressure of the gas phase refrigerant and the dynamic pressure of the liquid phase refrigerant CC, the greater the force with which the gas phase refrigerant presses the liquid phase refrigerant CC against the upstream end 51a of the mixing section 51 when the gas phase refrigerant flowing into the mixing section 51 from the recessed section 53 and the liquid phase refrigerant CC flowing into the mixing section 51 from the inlet 510 collide. The greater the force with which the gas phase refrigerant presses the liquid phase refrigerant CC against the upstream end 51a of the mixing section 51, the more the liquid phase refrigerant CC is prevented from directly flowing into the reference outlet pipe 52a, and the smaller the liquid phase refrigerant distribution rate of the reference outlet pipe 52a becomes.

FIG. 11 shows the relationship between the height h of the mixing section 51 and the liquid-phase refrigerant distribution rate of the reference outlet pipe 52a, obtained by simulation, when the types of refrigerants used are R290 and R134A, i.e., 1,1,1,2-tetrafluoroethane. In the example of FIG. 11, the mass flow rate G of the refrigerant is 50 [kg/h]. When the temperatures are the same, the density ratio ρ l /ρ g, which is the ratio of the liquid-phase density ρ _l to the gas-phase density ρ _g of R134A, is larger than the density ratio ρ _l /ρ _g of R290. As shown in FIG. 11, when the type of refrigerant is R134A with a large density ratio _{ρ l / ρ g ,} the height _h of the mixing section 51 at which the liquid-phase refrigerant distribution rate of the reference outlet pipe 52a becomes the minimum value is larger and the minimum value is smaller than when the type of refrigerant is R290 with a small _density ratio ρ l /ρ g. The larger the density ratio _ρl / _ρg of the refrigerant, the larger the difference between the velocity of the gas phase refrigerant and the velocity of the liquid phase refrigerant CC, and the larger the difference between the dynamic pressure of the gas phase refrigerant and the dynamic pressure of the liquid phase refrigerant CC. The larger the difference between the dynamic pressure of the gas phase refrigerant and the dynamic pressure of the liquid phase refrigerant CC, the more the liquid phase refrigerant CC is prevented from directly flowing into the reference outlet pipe 52a, and the smaller the liquid phase refrigerant distribution rate of the reference outlet pipe 52a.

The larger the mass flux of the refrigerant discharged from the inlet pipe 50, i.e., the mass flow rate per unit area, the smaller the liquid phase refrigerant distribution rate of the reference outlet pipe 52a. The mass flux of the refrigerant is proportional to the mass flow rate G of the refrigerant and inversely proportional to the square of the inner diameter Di of the inlet pipe 50.

As described above, the liquid-phase refrigerant distribution ratio of the reference outlet pipe 52a depends on the height h of the mixing section 51, the refrigerant mass flow rate G, the refrigerant density ratio _ρl / _ρg , and the refrigerant mass flux. In light of this, the following Equation 2 expressing the liquid-phase refrigerant distribution ratio X of the reference outlet pipe 52a was obtained by approximating the results of the simulation.

According to the results of the simulation, regardless of the height h of the mixing section 51, the mass flow rate G of the refrigerant, the type of refrigerant, and the temperature of the refrigerant, when the liquid-phase refrigerant distribution ratio X of the reference outlet pipe 52a is greater than 0.13, a portion of the liquid-phase refrigerant CC discharged from the inlet pipe 50 flows directly into the reference outlet pipe 52a, and when the liquid-phase refrigerant distribution ratio X of the reference outlet pipe 52a is less than 0.13, the liquid-phase refrigerant CC does not flow directly into the reference outlet pipe 52a. The range of the height h of the mixing section 51 where the liquid-phase refrigerant distribution ratio X of the reference outlet pipe 52a expressed by the above formula 2 is less than 0.13 is expressed by the above formula 1.

As described above, in this embodiment, the height h of the mixing section 51 satisfies the formula 1. In other words, the height h of the mixing section 51 is a value within the range expressed by the formula 1. As a result, the liquid-phase refrigerant distribution ratio X of the reference outlet pipe 52a expressed by the above formula 2 is smaller than 0.13, and the liquid-phase refrigerant CC contained in the refrigerant is suppressed from flowing directly into the reference outlet pipe 52a, regardless of the mass flow rate G of the refrigerant, the type of refrigerant, and the temperature of the refrigerant. In other words, since the height h of the mixing section 51 satisfies the formula 1, the mixing section 51 guides the refrigerant flowing in from the inlet 510 to flow along the upstream end 51a and the side wall 51d of the mixing section 51, regardless of the mass flow rate G of the refrigerant, the type of refrigerant, and the temperature of the refrigerant, thereby diffusing the refrigerant in the circumferential direction of the downstream end 51b of the mixing section 51, and then sending it out from the outlet 511. According to this configuration, regardless of the mass flow rate G of the refrigerant, the type of refrigerant, and the temperature of the refrigerant, the variation in the amount of the liquid-phase refrigerant CC sent out from each outlet 511 is reduced. In addition, by preventing the liquid phase refrigerant CC from flowing directly into the reference outlet pipe 52a, the variation in the amount of liquid phase refrigerant CC discharged from each outlet 511 caused by the inclination of the axis of the inlet pipe 50 relative to the gravity direction g is reduced.

A computer was used to simulate the flow of refrigerant inside the refrigerant distributor 31 when the height h of the mixing section 51 satisfies formula 1 when parameters such as the number of outlet pipes 52, the inner diameter Di of the inlet 510, the diameter Dc of the depression in the mixing section 51, the first distance Li, and the second distance Lo were set to various values. Regardless of the values of these parameters, the liquid-phase refrigerant CC was prevented from flowing directly into the reference outlet pipe 52a. In other words, when the height h of the mixing section 51 satisfies formula 1, the liquid-phase refrigerant CC is prevented from flowing directly into the reference outlet pipe 52a regardless of the number of outlet pipes 52, the inner diameter Di of the inlet 510, the diameter Dc of the depression in the mixing section 51, the first distance Li, and the second distance Lo. Furthermore, when the height h of the mixing section 51 was set to various values within the range satisfying the formula 1 and a similar simulation was performed, when the height h of the mixing section 51 was 2.5 mm or more and 4 mm or less, the liquid-phase refrigerant CC was significantly suppressed from flowing directly into the reference outlet pipe 52a, regardless of the values of the above-mentioned parameters. As described above, in this embodiment, the height h of the mixing section 51 is 2.5 mm or more and 4 mm or less. With this configuration, regardless of the mass flow rate G of the refrigerant, the type of refrigerant, the temperature of the refrigerant, the number of the outlet pipes 52, the inner diameter Di of the inlet 510, the diameter Dc of the recess of the mixing section 51, the first distance Li, and the second distance Lo, the variation in the amount of the liquid-phase refrigerant CC discharged from each outlet 511 is reduced.

As described above, in this embodiment, the height h of the mixing section 51 satisfies the above formula 1. As a result, the mixing section 51 guides the refrigerant flowing in from the inlet 510 to flow along the upstream end 51a of the mixing section 51 and the side wall 51d of the mixing section 51, and then diffuses the refrigerant in the circumferential direction of the downstream end 51b, and then sends it out from the outlet 511. With this configuration, regardless of the flow rate, type, and temperature of the gas-liquid two-phase refrigerant flowing in from the inlet 510, the variation in the amount of refrigerant sent out from each outlet 511 is reduced. As a result, the variation in the amount of refrigerant distributed from each outlet 511 to the heat transfer tube 30 through each outlet tube 52 connected to each outlet 511 is reduced regardless of the flow rate, type, and temperature of the refrigerant. That is, with this configuration, when distributing the refrigerant to a plurality of heat transfer tubes 30, the variation in the amount of refrigerant distributed to each heat transfer tube 30 can be reduced regardless of the flow rate, type, and temperature of the refrigerant.

The refrigerant distributor 31 reduces the variation in the amount of refrigerant distributed to each heat transfer tube 30, thereby reducing the variation in the thermal load of the refrigerant in each heat transfer tube 30 and reducing the variation in the section in which the refrigerant flows in a single-phase gas state in each heat transfer tube 30. This improves the heat exchange efficiency of the indoor heat exchanger 3 and outdoor heat exchanger 4, which are equipped with the refrigerant distributor 31 and function as evaporators, and improves the air conditioning efficiency of the air conditioner 100 equipped with the indoor heat exchanger 3 and outdoor heat exchanger 4.

In addition, in this embodiment, the diameter Dc of the recess in the mixing section 51 is larger than the inner diameter Di of the inlet 510. With this configuration, it is possible to reduce the variation in the amount of refrigerant discharged from each outlet 511.

In addition, in this embodiment, the outlet 511 is disposed radially outward from the recess formed in the mixing section 51 at the downstream end 51b of the mixing section 51. The first distance Li, which is the distance between the recess of the mixing section 51 and the axis QQ of the outlet 511, is greater than the second distance Lo, which is the distance between the axis QQ of the outlet 511 and the side wall 51d of the mixing section 51. This configuration facilitates processing when manufacturing the refrigerant distributor 31 and reduces manufacturing costs.

In this embodiment, the diameter Dc of the recess in the mixing section 51 is described as being larger than the inner diameter Di of the inlet 510, but this is merely an example. The diameter Dc of the recess in the mixing section 51 may be equal to or smaller than the inner diameter Di of the inlet 510.

In the present embodiment, the first distance Li is described as being greater than the second distance Lo, but this is merely an example. The first distance Li may be equal to or less than the second distance Lo.

In this embodiment, the height h of the mixing section 51 has been described as being 2.5 mm or more and 4 mm or less, but this is merely an example, and the height h of the mixing section 51 may be any value that satisfies formula 1.

(Embodiment 2)
Hereinafter, a second embodiment of the present disclosure that reduces the pressure loss of the refrigerant inside the refrigerant distributor 31 will be described, focusing on the differences from the first embodiment.

When pressure loss of the refrigerant occurs inside the refrigerant distributor 31 provided in the indoor heat exchanger 3 and the outdoor heat exchanger 4 that function as evaporators, the pressure of the gas-phase refrigerant flowing from the evaporator into the compressor 1 decreases. This increases the amount of energy that must be given to the gas-phase refrigerant to change the low-pressure gas-phase refrigerant that has flowed into the compressor 1 into high-pressure gas-phase refrigerant, and in order to supply this energy, it becomes necessary to increase the frequency of the compressor 1. Increasing the frequency of the compressor 1 reduces the energy-saving performance of the air conditioner 100.

The smaller the gas phase density _ρg of the refrigerant, the greater the flow velocity of the refrigerant in the gas phase and the greater the pressure loss of the refrigerant inside the refrigerant distributor 31. When the gas phase density _ρg of the refrigerant is 20 kg/ ^m3 or less, the reduction in the energy saving performance of the air conditioner 100 caused by the pressure loss of the refrigerant inside the refrigerant distributor 31 is large enough to not be negligible. In this embodiment, the gas phase density _ρg of the refrigerant is 20 kg/ ^m3 or less.

In this embodiment, the height h of the mixing section 51 satisfies the above formula 1 and is greater than 10/3 [mm] and is equal to or less than 4 [mm]. As described later, this configuration reduces the pressure loss of the refrigerant inside the refrigerant distributor 31, and improves the energy saving performance of the air conditioner 100.

The following describes the reduction in pressure loss of the refrigerant inside the refrigerant distributor 31, using the results of a computer-simulation of the flow of the refrigerant inside the refrigerant distributor 31 when a single-phase gas refrigerant flows into the inlet pipe 50. This simulation was performed under the following conditions: diameter Dc of the recess in the mixing section 51 = 7 mm, inner diameter Di of the inlet 510 = 6 mm, first distance Li = 8.5 mm, second distance Lo = 2.5 mm. In this simulation, R290 was used as the refrigerant. The temperature of the refrigerant in the simulation was 10°C.

Figure 12 shows the relationship between the height h of the mixing section 51 and the pressure loss ΔP [kPa] of the refrigerant inside the refrigerant distributor 31 when the mass flow rate G of the refrigerant in a single-phase gas phase state flowing into the inlet pipe 50 is 50 [kg/h], 100 [kg/h], 150 [kg/h], or 200 [kg/h], as determined by simulation. The pressure loss ΔP of the refrigerant inside the refrigerant distributor 31 is the difference between the pressure of the refrigerant when it flows into the inlet pipe 50 and the pressure of the refrigerant when it is discharged from the outlet pipe 52. As shown in Figure 12, regardless of the mass flow rate G of the refrigerant, the greater the height h of the mixing section 51, the smaller the pressure loss ΔP of the refrigerant.

The pressure loss ΔP of the refrigerant is proportional to the square of the velocity of the refrigerant. The velocity of the refrigerant is proportional to the mass flow rate G of the refrigerant and inversely proportional to the square root of the gas phase density _ρg of the refrigerant. Therefore, the pressure loss ΔP of the refrigerant can be expressed by the following formula 3. In formula 3, f(h) is a function with the height h of the mixing section 51 as a variable.

By approximating the simulation results, the following equation 4 was obtained, which represents the above function f(h).

As is clear from the above formula 3, the smaller the value of the function f(h), the smaller the pressure loss ΔP of the refrigerant. As is clear from the above formula 4, the larger the height h of the mixing section 51, the smaller the value of the function f(h). Therefore, the larger the height h of the mixing section 51, the smaller the pressure loss ΔP of the refrigerant. The larger the height h of the mixing section 51, the smaller the degree of bending of the refrigerant when the refrigerant flowing in from the inlet 510 bends inside the mixing section 51 and flows into each outlet 511. In other words, the larger the height h of the mixing section 51, the easier it is for the refrigerant to flow inside the refrigerant distributor 31. Therefore, the larger the height h of the mixing section 51, the smaller the pressure loss ΔP of the refrigerant. Hereinafter, the pressure loss ΔP of the refrigerant when the height h of the mixing section 51 is infinite is referred to as the reference pressure loss. In addition, hereinafter, the ratio of the pressure loss ΔP of the refrigerant to the reference pressure loss is referred to as the pressure loss ratio.

The larger the height h of the mixing section 51, the more gradually the increase in the value of the function f(h) when the height h of the mixing section 51 increases by a unit amount. Therefore, the larger the height h of the mixing section 51, the more gradually the decrease in the refrigerant pressure loss ΔP when the height h of the mixing section 51 increases by a unit amount.

When the pressure loss ratio is within 130%, the amount of reduction in the refrigerant pressure loss ΔP when the height h of the mixing section 51 is increased by a unit amount is extremely small. Therefore, when the pressure loss ratio is within 130%, it is extremely difficult to reduce the refrigerant pressure loss ΔP by increasing the height h of the mixing section 51. Therefore, when the pressure loss ratio is within 130%, the refrigerant pressure loss ΔP is substantially at a minimum value.

According to the results of the simulation, the pressure loss ratio is within 130% when the height h of the mixing section 51 is greater than 10/3 [mm]. As described above, in this embodiment, the height h of the mixing section 51 is greater than 10/3 [mm]. With such a configuration, the pressure loss ΔP of the refrigerant can be suppressed to a practical minimum value. This improves the energy saving performance of the air conditioner 100. In addition, a computer was used to perform a simulation of the flow of refrigerant inside the refrigerant distributor 31 when the height h of the mixing section 51 is greater than 10/3 [mm] when various simulation conditions such as the mass flow rate G of the refrigerant, the type of refrigerant, the temperature of the refrigerant, the number of outlet pipes 52, the inner diameter Di of the inlet pipe 50, the diameter Dc of the depression of the mixing section 51, the first distance Li, and the second distance Lo were set under various conditions. As a result, the pressure loss ratio was within 130% regardless of these simulation conditions. In other words, when the height h of the mixing section 51 is greater than 10/3 [mm], the pressure loss ratio is suppressed to within 130%, regardless of the mass flow rate G of the refrigerant, the type of refrigerant, the temperature of the refrigerant, the number of outlet pipes 52, the inner diameter Di of the inlet pipe 50, the diameter Dc of the depression in the mixing section 51, the first distance Li, and the second distance Lo.

As described above, in this embodiment, the height h of the mixing section 51 is greater than 10/3 mm. This configuration reduces the pressure loss ΔP of the refrigerant inside the refrigerant distributor 31, improving the energy-saving performance of the air conditioner 100.

In the present embodiment, the height h of the mixing section 51 is described as being 4 mm or less, but this is merely an example, and the height h of the mixing section 51 may be any value that satisfies Formula 1 and is greater than 10/3 mm. As an example, when the diameter Dc of the recess of the mixing section 51 is 7 mm, the inner diameter Di of the inlet 510 is 6 mm, the first distance Li is 8.5 mm, and the second distance Lo is 2.5 mm, the height h of the mixing section 51 may be any value included in the region FF shown in FIG. 13. In the example of FIG. 13, R290 is used as the refrigerant, and the temperature of the refrigerant is 10° C. In FIG. 13, the region where the height h of the mixing section 51 is smaller than the straight line DD is the region where the height h of the mixing section 51 is smaller than 10/3 mm, and the region where the height h of the mixing section 51 is greater than the straight line DD is the region where the height h of the mixing section 51 is greater than 10/3 mm. The region where the mass flow rate G of the refrigerant is smaller than the curve EE is the region where the height h of the mixing section 51 does not satisfy the mathematical formula 1, and the region where the mass flow rate G of the refrigerant is larger than the curve EE is the region where the height h of the mixing section 51 satisfies the mathematical formula 1. The region FF where the height h of the mixing section 51 is larger than the straight line DD and the mass flow rate G of the refrigerant is larger than the curve EE is the region where the height h of the mixing section 51 satisfies the mathematical formula 1 and is larger than 10/3 [mm].

(Embodiment 3)
Hereinafter, a third embodiment of the present disclosure in which the refrigerant distributor 31 includes a guide section that guides the gas phase refrigerant to the upstream end 51a of the mixer 51 will be described, focusing on the differences from the first embodiment.

The refrigerant distributor 31 according to this embodiment differs from the refrigerant distributor 31 according to the first embodiment in that it includes an induction section 54 connected to the downstream end 51b of the mixing section 51, as shown in FIG. 14(A). In FIG. 14(A), the induction section 54 is shaded for ease of understanding. In a front view, the induction section 54 has a circular ring shape whose axis is the same as that of the mixing section 51 and the recessed section 53. The induction section 54 is disposed away from the recessed section 53 toward the radial outside of the downstream end 51b of the mixing section 51. That is, the induction section 54 is disposed away from the recess formed in the mixing section 51, which is the space inside the recessed section 53, toward the radial outside of the downstream end 51b of the mixing section 51. In addition, the induction section 54 is disposed away from the outlet 511 and the outlet pipe 52 toward the radial inside of the downstream end 51b of the mixing section 51.

As shown in FIG. 14(B), the induction section 54 is provided so as to protrude in a direction approaching the upstream end 51a of the mixing section 51. FIG. 14(B) is a cross-sectional view of the refrigerant distributor 31 according to this embodiment taken along line A-A in FIG. 14(A). The induction section 54 has a first side wall 54a inclined relative to the downstream end 51b of the mixing section 51, and a second side wall 54b perpendicular to the downstream end 51b of the mixing section 51. The first side wall 54a is an example of an induction side wall. The second side wall 54b is disposed radially outward of the downstream end 51b of the mixing section 51 relative to the first side wall 54a.

The first side wall 54a forms an angle θ of 45° or more and less than 90° with respect to the downstream end 51b of the mixing section 51. The first side wall 54a has an inner end 60 and an outer end 61 that is spaced radially outward from the inner end 60 of the downstream end 51b of the mixing section 51. The inner end 60 of the first side wall 54a is connected to the downstream end 51b of the mixing section 51. The outer end 61 of the first side wall 54a is connected to the second side wall 54b. The third distance Lp, which is the distance between the outer end 61 of the first side wall 54a and the upstream end 51a of the mixing section 51, is smaller than the fourth distance Lq, which is the distance between the inner end 60 of the first side wall 54a and the upstream end 51a of the mixing section 51. That is, the outer end 61 of the first side wall 54a is positioned closer to the upstream end 51a of the mixer section 51 than the inner end 60 of the first side wall 54a.

15 shows an example of the flow of refrigerant inside the refrigerant distributor 31 in the case where the refrigerant in a gas-liquid two-phase state flows into the refrigerant distributor 31 according to the present embodiment with the liquid-phase refrigerant CC contained in the refrigerant biased in the +X-axis direction. FIG. 15 shows a longitudinal section of the refrigerant distributor 31 cut along a cut surface that includes the axis of the inlet pipe 50 and is perpendicular to the Y-axis direction. In FIG. 15, the arrow AA indicates the flow of the liquid-phase refrigerant CC, and the arrow BB indicates the flow of the gas-phase refrigerant. After flowing into the recess 53, the gas-phase refrigerant that flows from the recess 53 into the mixing section 51 collides with the liquid-phase refrigerant CC that flows into the mixing section 51 from the inlet 510 inside the mixing section 51. After colliding with the gas-phase refrigerant, the liquid-phase refrigerant CC flows along the upstream end 51a of the mixing section 51 toward the side wall 51d of the mixing section 51, as shown by the arrow AA. On the other hand, after colliding with the liquid phase refrigerant CC, the gas phase refrigerant flows along the downstream end 51b of the mixing section 51, as shown by arrow BB, toward the side wall 51d of the mixing section 51, and reaches the induction section 54.

The gas phase refrigerant that reaches the induction section 54 flows from the downstream end 51b of the mixing section 51 to the upstream end 51a along the first side wall 54a of the induction section 54. That is, the gas phase refrigerant is guided from the downstream end 51b of the mixing section 51 to the upstream end 51a by the first side wall 54a of the induction section 54. This suppresses the flow of the gas phase refrigerant into the reference outlet pipe 52a, and suppresses the liquid phase refrigerant CC from flowing directly into the reference outlet pipe 52a by being dragged by the gas phase refrigerant flowing into the outlet 511. By suppressing the direct flow of the liquid phase refrigerant CC into the reference outlet pipe 52a, the liquid phase refrigerant distribution rate X of the reference outlet pipe 52a is suppressed, and the variation in the amount of liquid phase refrigerant CC sent out from each outlet 511 is reduced.

According to this configuration, even if the height h of the mixing section 51 is smaller than the size required to suppress the liquid-phase refrigerant distribution ratio X of the reference outlet pipe 52a, as in the example of Figure 9 (B) described above, the induction section 54 suppresses the flow of the gas-phase refrigerant into the reference outlet pipe 52a. This prevents the liquid-phase refrigerant CC from flowing directly into the reference outlet pipe 52a, suppressing the liquid-phase refrigerant distribution ratio X of the reference outlet pipe 52a.

As described above, the first side wall 54a of the induction section 54 forms an angle θ of 45° or more and less than 90° with respect to the downstream end 51b of the mixing section 51. With this configuration, the gas phase refrigerant is easily guided to the upstream end 51a of the mixing section 51 by the first side wall 54a, and the outflow of the gas phase refrigerant to the reference outlet pipe 52a can be more effectively suppressed. This more effectively suppresses the liquid phase refrigerant CC from flowing directly into the reference outlet pipe 52a, more effectively suppresses the liquid phase refrigerant distribution rate X of the reference outlet pipe 52a, and more effectively suppresses the variation in the amount of liquid phase refrigerant CC discharged from each outlet 511.

As described above, in this embodiment, the refrigerant distributor 31 guides the gas phase refrigerant that has flowed into the mixing section 51 from the downstream end 51b to the upstream end 51a of the mixing section 51 by the guide section 54 connected to the downstream end 51b of the mixing section 51. This configuration prevents the liquid phase refrigerant CC from flowing directly into the reference outlet pipe 52a, suppresses the liquid phase refrigerant distribution rate X of the reference outlet pipe 52a, and reduces the variation in the amount of liquid phase refrigerant CC discharged from each outlet 511.

In this embodiment, the induction section 54 has been described as being provided so as to protrude in a direction approaching the upstream end 51a of the mixing section 51, but this is merely one example. The induction section 54 may be provided so as to protrude in a direction away from the upstream end 51a of the mixing section 51, as shown in FIG. 16. FIG. 16 is a vertical cross-sectional view of the refrigerant distributor 31 according to this modified example, cut along a cut surface that includes the axis of the inlet pipe 50 and is perpendicular to the Y-axis direction. In the modified example shown in FIG. 16, the second side wall 54b of the induction section 54 is disposed radially inward of the downstream end 51b of the mixing section 51 relative to the first side wall 54a. In this modified example, as in the above-mentioned embodiment 3, the first side wall 54a forms an angle θ of 45° or more and less than 90° with respect to the downstream end 51b of the mixing section 51. The inner end 60 of the first side wall 54a is connected to the second side wall 54b. The outer end 61 of the first side wall 54a is connected to the downstream end 51b of the mixing section 51. In this modification, similar to the above-mentioned third embodiment, the third distance Lp, which is the distance between the outer end 61 of the first side wall 54a and the upstream end 51a of the mixing section 51, is smaller than the fourth distance Lq, which is the distance between the inner end 60 of the first side wall 54a and the upstream end 51a of the mixing section 51. That is, the outer end 61 of the first side wall 54a is disposed closer to the upstream end 51a of the mixing section 51 than the inner end 60 of the first side wall 54a.

In this embodiment, the second side wall 54b of the induction section 54 is described as being perpendicular to the downstream end 51b of the mixing section 51, but this is merely an example. The second side wall 54b of the induction section 54 may be configured to form an angle of less than 90° with respect to the downstream end 51b of the mixing section 51.

(Modification)
Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the gist of the present disclosure.

For example, in the above first to third embodiments, the air conditioner 100 has been described as a specific example of a refrigeration cycle device, but this is merely one example. The refrigeration cycle device according to the present disclosure may be a refrigeration cycle device other than an air conditioner, such as a heat pump water heater, a refrigerator, or a freezer.

In the above embodiments 1 to 3, the indoor heat exchanger 3 and the outdoor heat exchanger 4, which are examples of heat exchangers, have been described as causing the refrigerant to exchange heat with air, but this is merely one example. The heat exchanger according to the present disclosure can cause the refrigerant to exchange heat with any substance. For example, when the heat exchanger according to the present disclosure is provided in a heat pump water heater, the heat exchanger causes the refrigerant to exchange heat with water.

In the above embodiments 1 to 3, the refrigerant distributor 31 has been described as being disposed at the inlets of the indoor heat exchanger 3 and the outdoor heat exchanger 4, but this is merely one example. The refrigerant distributor according to the present disclosure may be disposed midway through the heat exchanger. Specifically, a reheat dehumidification type air conditioner is known in which a throttling device is disposed midway through the refrigerant path of the indoor heat exchanger, and during cooling operation, multiple refrigerant paths located upstream of the throttling device function as condensers, and multiple refrigerant paths located downstream of the throttling device function as evaporators. In such a reheat dehumidification type air conditioner, the refrigerant distributor according to the present disclosure may be disposed midway through the refrigerant path of the indoor heat exchanger, and the refrigerant may be distributed to multiple refrigerant paths downstream of the throttling device.

In the above embodiments 1 to 3, the number of heat transfer tubes 30 and outlet tubes 52 is described as eight, but this is merely an example. The number of heat transfer tubes 30 and outlet tubes 52 may be any number equal to or greater than two.

In the above embodiments 1 to 3, the recessed portion 53 has been described as having a shape of a cylinder connected to a cone, but this is merely one example. The shape of the recessed portion 53 may be any shape. For example, the shape of the recessed portion 53 may be a hemisphere.

In the above embodiments 1 to 3, the inner diameter of the inlet pipe 50 is described as being equal to the inner diameter of the straight pipe section 41 of the internal refrigerant pipe 32, but this is merely one example. The inner diameter of the inlet pipe 50 may be different from the inner diameter of the straight pipe section 41. In this case, the method of connecting the inlet pipe 50 and the straight pipe section 41 is arbitrary. For example, the inlet pipe 50 and the straight pipe section 41 may be connected via a pipe having a tapered shape with an inner diameter that tapers. Alternatively, the inlet pipe 50 and the straight pipe section 41 may be connected via a stepped rod-shaped pipe.

In the above embodiments 1 to 3, the internal refrigerant piping 32 is described as being connected to the inlet 510 via the inlet pipe 50, but this is merely an example, and the internal refrigerant piping 32 may be directly connected to the inlet 510. In this case, the end of the internal refrigerant piping 32 functions as the inlet pipe 50.

In the above embodiments 1 to 3, each heat transfer tube 30 is described as being connected to each outlet 511 via each outlet tube 52, but this is merely an example, and each heat transfer tube 30 may be directly connected to the outlet 511. In this case, the end of each heat transfer tube 30 functions as the outlet tube 52.

The above-mentioned embodiments 1 to 3 can be combined with each other. As an example, the induction section 54 of embodiment 3 may be provided in the refrigerant distributor 31 of embodiment 2. With such a configuration, it is possible to reduce the variation in the amount of refrigerant sent out from each outlet pipe 52, as well as reduce the pressure loss of the refrigerant inside the refrigerant distributor 31, thereby improving the energy saving performance of the air conditioner 100.

Various embodiments and modifications of the present disclosure are possible without departing from the broad spirit and scope of the present disclosure. Furthermore, the above-described embodiments are intended to explain the present disclosure and do not limit the scope of the present disclosure. In other words, the scope of the present disclosure is indicated by the claims, not the embodiments. Various modifications made within the scope of the claims and within the scope of the disclosure equivalent thereto are deemed to be within the scope of the present disclosure.

This application is based on Japanese Patent Application No. 2022-019015, filed on February 9, 2022. The entire specification, claims and drawings of Japanese Patent Application No. 2022-019015 are incorporated herein by reference.

1 Compressor, 2 Throttle device, 3 Indoor heat exchanger, 4 Outdoor heat exchanger, 5 Main refrigerant piping, 6 Indoor unit, 7 Outdoor unit, 10 Refrigerant circuit, 20 Control device, 30 Heat transfer tube, 31 Refrigerant distributor, 32 Internal refrigerant piping, 39 Connection portion, 39a Axis of connection portion, 40 Curved portion, 41 Straight pipe portion, 41a Axis of straight pipe portion, 50 Inlet pipe, 51 Mixing portion, 51a Upstream end portion, 51b Downstream end portion, 51c Opening portion, 51d Side wall, 52 Outlet pipe, 52a Reference outlet pipe, 53 Depression portion, 54 Induction portion, 54a First side wall, 54b Second side wall, 60 Inner end portion, 61 Outer end portion, 100 Air conditioner, 510 Inlet, 511 Outlet, AA Flow of liquid phase refrigerant, BB Flow of gas phase refrigerant, CC liquid phase refrigerant, DD straight line, EE curve, FF area, Dc diameter of depression in mixing section, Di inner diameter of inlet, h height of mixing section, Li first distance, Lo second distance, Lp third distance, Lq fourth distance, MM saturated liquid line, NN saturated vapor line, QQ axial center of outlet, TL straight line passing through the axial center of connection section and the axial center of straight pipe section.

Claims (14)

A mixing portion having a cylindrical shape is provided,
An inlet through which the refrigerant flows is formed at a first end of the mixing section,
A plurality of outlets through which the refrigerant flows out are formed at a second end of the mixing portion opposite to the first end,
A recess facing the inlet is formed at the second end of the mixing portion,
the mixing portion guides the gas phase refrigerant contained in the refrigerant that has flowed into the recess from the inlet to collide with the liquid phase refrigerant contained in the refrigerant that has flowed in from the inlet, thereby pressing the liquid phase refrigerant against the first end of the mixing portion, guiding the liquid phase refrigerant to flow along the first end of the mixing portion and a side wall of the mixing portion, diffusing the liquid phase refrigerant in a circumferential direction of the second end, and then sending the liquid phase refrigerant out of the outlet;
a guide portion disposed at the second end of the mixing portion,
The guide portion guides the gas phase refrigerant that has been guided to the mixing portion and collided with the liquid phase refrigerant from the second end portion of the mixing portion to the first end portion of the mixing portion.
Refrigerant distributor. The induction portion is disposed away from the recess toward the radially outer side of the second end of the mixing portion, and is disposed away from the outlet toward the radially inner side of the second end of the mixing portion,
the induction section includes an induction sidewall inclined relative to a main surface of the second end of the mixing section;
The induction sidewall has an inner end and an outer end spaced radially outward from the inner end of the mixing section at the second end,
the outer end of the guiding sidewall is disposed closer to the first end of the mixing section than the inner end of the guiding sidewall;
2. The refrigerant distributor of claim 1. The refrigerant is in a gas-liquid two-phase state,
The inner diameter of the inlet is Di [mm], the mass flow rate of the refrigerant is G [kg/h], and the gas phase density of the refrigerant is ρ _g [kg/m ³ ], and the liquid phase density of the refrigerant is ρ _l [kg/m ³ ], the height h [mm] of the mixing portion, which is the distance between the first end and the second end in the internal space of the mixing portion, satisfies Formula 1.
3. A refrigerant distributor according to claim 1 or 2.
A mixing portion having a cylindrical shape is provided,
An inlet through which the refrigerant flows is formed at a first end of the mixing section,
A plurality of outlets through which the refrigerant flows out are formed at a second end of the mixing portion opposite to the first end,
A recess facing the inlet is formed at the second end of the mixing portion,
the mixing section guides the refrigerant that has flowed in from the inlet to flow along the first end of the mixing section and a side wall of the mixing section, diffusing the refrigerant in a circumferential direction of the second end, and then sends the refrigerant out from the outlet,
The diameter of the recess is larger than the inner diameter of the inlet,
The refrigerant is in a gas-liquid two-phase state,
When the inner diameter of the inlet is Di [mm], the mass flow rate of the refrigerant is G [kg/h], the gas phase density of the refrigerant is ρ _g [kg/m ³ ], and the liquid phase density of the refrigerant is ρ _l [kg/m ³ ], the height h [mm] of the mixing portion, which is the distance between the first end and the second end in the internal space of the mixing portion, satisfies Equation 2.
Refrigerant distributor.
The mixing section guides the gas phase refrigerant contained in the refrigerant that has flowed into the recess so as to collide with the liquid phase refrigerant contained in the refrigerant that has flowed in from the inlet, thereby pressing the liquid phase refrigerant against the first end of the mixing section, guiding the liquid phase refrigerant to flow along the first end of the mixing section and a side wall of the mixing section, diffusing the liquid phase refrigerant in a circumferential direction of the second end, and then sending the liquid phase refrigerant out from the outlet.
Refrigerant distributor according to claim 4 . a guide portion disposed at the second end of the mixing portion,
The induction portion is disposed away from the recess toward the radially outer side of the second end of the mixing portion, and is disposed away from the outlet toward the radially inner side of the second end of the mixing portion,
the induction section includes an induction sidewall inclined relative to a main surface of the second end of the mixing section;
The induction sidewall has an inner end and an outer end spaced radially outward from the inner end of the mixing section at the second end,
the outer end of the guiding sidewall is disposed closer to the first end of the mixing section than the inner end of the guiding sidewall;
6. A refrigerant distributor according to claim 4 or 5 . the outlet is disposed radially outwardly of the second end of the mixing section from the recess;
A first distance between the recess and the axis of the outlet is greater than a second distance between the axis of the outlet and a side wall of the mixing section.
Refrigerant distributor according to claim 1 or 4 . The height h of the mixing portion is 2.5 mm or more and 4 mm or less.
Refrigerant distributor according to claim 1 or 4 . an inlet pipe connected to the inlet;
an outlet pipe connected to the outlet;
Further comprising:
Refrigerant distributor according to claim 1 or 4 . The height h of the mixing portion is greater than 10/3 [mm];
Refrigerant distributor according to claim 1 or 4 . A refrigerant distributor according to claim 1 or 4 ;
A plurality of heat transfer tubes connected to the outlet;
Equipped with
heat exchanger. A refrigerant circuit is provided to circulate the refrigerant.
The refrigerant circuit includes the heat exchanger according to claim 11, a compressor that compresses the refrigerant, and a throttling device that expands the refrigerant.
Equipped with
Refrigeration cycle equipment. A refrigerant distributor according to claim 1 or 4 ;
An internal refrigerant pipe connected to the inlet;
Equipped with
The internal refrigerant piping includes a straight pipe portion having a linear shape and connected to the inlet, and a curved portion located upstream of the straight pipe portion, having a U-shape, and connected to the straight pipe portion.
heat exchanger. A refrigerant circuit is provided to circulate the refrigerant.
The refrigerant circuit includes the heat exchanger according to claim 13, a compressor that compresses the refrigerant, and a throttling device that expands the refrigerant.
Equipped with
Refrigeration cycle equipment.

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