JP7338180B2 - Ejector - Google Patents

Description

The present invention relates to an ejector and a cooling system to which the ejector is applied.

For example, some circuits for circulating refrigerant include an ejector. The ejector includes a nozzle portion through which a driving fluid is ejected from an ejection port at the tip thereof, a body portion disposed so as to surround the nozzle portion and having a hollow portion provided in a portion extending from the ejection port of the nozzle portion, and a suction passage connected to open to the hollow portion of the main body. In this ejector, when the refrigerant is ejected from the ejection port of the nozzle portion as the driving fluid, the external refrigerant is sucked into the hollow portion of the main body through the suction passage, and after the sucked fluid and the driving fluid are mixed, the diffuser portion and is discharged from the discharge port (see, for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2008-64021

By the way, the diffuser section that pressurizes the refrigerant needs to be tapered so that the inner diameter gradually increases toward the downstream side. For this reason, in the diffuser portion, a vortex is generated due to separation of the boundary layer from the wall surface, which may lead to a situation in which the efficiency of the pump is lowered.

SUMMARY OF THE INVENTION An object of the present invention is to provide an ejector and a cooling system that can prevent a situation in which the pump efficiency is lowered.

In order to achieve the above object, an ejector according to the present invention mixes a driving fluid ejected from a nozzle portion and a sucked fluid sucked as the driving fluid is ejected, and then pressurizes and ejects the fluid in a diffuser portion. a chamber provided around the diffuser section and communicating with a hollow portion of the diffuser section through a communication hole provided in a peripheral wall of the diffuser section; and a decompression path for applying the suction pressure of the suction fluid to the interior of the chamber.

Further, according to the present invention, in the ejector described above, the communication holes are opened so as to have a rotationally symmetrical shape on the same circumference around the axis of the diffuser portion.

Further, according to the present invention, in the ejector described above, a plurality of communication holes having the same shape are opened at equal intervals.

Further, in the ejector of the present invention, the body portion is provided so as to cover the periphery of the nozzle portion, has a downstream end portion connected to the diffuser portion, and is supplied with the suction fluid between itself and the nozzle portion. wherein the decompression path is connected to a portion of the main body portion upstream of the tip of the nozzle portion.

Further, the cooling system according to the present invention is provided with a circulation pump, a heating heat exchanger, and a condenser, a circulation path for sequentially circulating a refrigerant therebetween by driving the circulation pump, and a circulation path provided in the circulation path, the above-described ejector in which the refrigerant heated in the heating heat exchanger is supplied as the driving fluid to the nozzle portion, and the refrigerant that has passed through the diffuser portion is supplied to the condenser; a branch path branching from a portion located between the vessel and the circulation pump to supply the refrigerant as the suction fluid to the ejector; an expansion mechanism provided in the branch path for decompressing the refrigerant; and an evaporator that exchanges heat between the refrigerant depressurized in and the medium to be cooled, and the decompression path is connected to a portion downstream of the expansion mechanism in the branch path. .

According to the present invention, the suction pressure of the suction fluid acting on the chamber reduces the pressure of the peripheral wall portion of the diffuser portion through the communication hole, so that the refrigerant passing through the diffuser portion is sucked, thereby suppressing boundary layer separation. As a result, it is possible to prevent a situation in which the pump efficiency is lowered.

FIG. 1 is a circuit diagram of a cooling system to which an ejector according to an embodiment of the invention is applied. 2 is a sectional view of an ejector applied to the cooling system shown in FIG. 1. FIG. 3 is a sectional view showing a modification of the ejector shown in FIG. 2. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of an ejector and a cooling system according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows a cooling system to which an ejector that is an embodiment of the invention is applied. The cooling system exemplified here cools the medium to be cooled by recovering waste heat from waste water such as factory waste water and used cooling water. 2. A heating heat exchanger 3, an ejector 4, and a condenser 5 are provided. The medium to be cooled can be water, oil, or other refrigerants. In particular, the present embodiment exemplifies a cooling system that generates cold water from water to be cooled using exhaust heat recovered from waste hot water.

The circulation pump 2 circulates and supplies the coolant in the coolant pipeline 1 . More specifically, the circulating pump 2 is, for example, a liquid-phase pump, which boosts the refrigerant to the drive pressure of the ejector 4 and supplies it. The heating heat exchanger 3 evaporates the refrigerant in the refrigerant pipe 1 supplied from the circulation pump 2 by exchanging heat with the waste hot water supplied to the hot water pipe 6 . The ejector 4 mixes the vapor-phase refrigerant that has passed through the heating heat exchanger 3 and the vapor-phase refrigerant supplied from a branch pipeline (branch path) 7, which will be described later, and pressurizes it and discharges it downstream. be. The condenser 5 condenses the refrigerant in the refrigerant pipe 1 by exchanging heat between the vapor-phase refrigerant discharged from the ejector 4 and the cooling water supplied to the cooling water pipe 8 . .

A branch line 7 is also provided in the cooling system. The branch pipe 7 branches off from the refrigerant pipe 1 after passing through the condenser 5 and serves as a suction passage for supplying part of the refrigerant flowing through the refrigerant pipe 1 to the ejector 4 as a suction fluid. The branch pipe 7 is provided with an expansion mechanism 9 and an evaporator 10 . The expansion mechanism 9 expands the refrigerant branched and supplied through the condenser 5 to reduce the pressure. The evaporator 10 evaporates the refrigerant by exchanging heat between the liquid-phase refrigerant that has passed through the expansion mechanism 9 and the water to be cooled supplied to the water-to-be-cooled pipe line 11 . An electronic expansion valve is most suitable for the expansion mechanism 9, but a manual expansion valve, a constant pressure expansion valve, a temperature expansion valve, an orifice, a capillary, or the like may be appropriately selected according to the application and configuration.

FIG. 2 shows details of the ejector 4 applied to the cooling system described above. As shown in the figure, the ejector 4 comprises a nozzle portion 20, a body portion 30, and a diffuser portion 40. As shown in FIG.

The nozzle portion 20 has a tubular shape with a circular cross section having a refrigerant passage 21 in the center. The tip portion of the nozzle portion 20 located on the right side in FIG. 2 has a tapered shape in which the outer diameter gradually decreases toward the tip. The coolant passage 21 of the nozzle portion 20 has a tapered shape in which the inner diameter gradually decreases toward the tip, and is opened at the tip surface of the nozzle portion 20 as an injection port 21a. A base end portion of the nozzle portion 20 is connected to the refrigerant pipe line 1 after passing through the heating heat exchanger 3 .

The main body part 30 has a cylindrical shape with a circular cross section having a hollow part 31 in the center, and is closed at the proximal end and open at the distal end. The main body portion 30 is arranged so that the axis 30C is aligned with the axis 20C of the nozzle portion 20. As shown in FIG. In the hollow portion 31 of the body portion 30, a suction portion 31a, a confluence portion 31b, and a mixing portion 31c are sequentially formed from the proximal end to the distal end.

The suction portion 31 a is a portion surrounding the nozzle portion 20 . In this embodiment, the suction portion 31a is configured such that the proximal end portion is cylindrical with a constant inner diameter, and the distal end portion is tapered such that the inner diameter gradually decreases toward the distal end. An annular suction space 32 is formed between the suction portion 31 a and the nozzle portion 20 . A branch pipe line 7 is connected to the peripheral surface of the suction portion 31 a so as to communicate with the suction space 32 . Although not shown in the drawing, the axis 7C of the branch pipeline 7 is displaced from the axis 30C of the main body 30 on a virtual plane perpendicular to the axis 30C of the main body 30. It is preferable to set it so as to be in a twisted position with respect to the axis 30C.

The confluence portion 31b is a tapered portion that continues to the tip of the suction portion 31a and has an inner diameter that gradually decreases toward the tip. The inner diameter of the proximal end of the merging portion 31b is configured to be larger than the injection port 21a of the nozzle portion 20. As shown in FIG. The mixing portion 31c is a portion having a constant inner diameter whose base end is continuous with the tip of the confluence portion 31b. As is clear from the drawing, the main body portion 30 is provided with an outer peripheral flange 33 at the tip of the mixing portion 31c. The suction portion 31a, the merging portion 31b, and the mixing portion 31c are provided on the axis 30C of the main body portion 30. As shown in FIG.

The diffuser portion 40 has a cylindrical shape with a circular cross section having a hollow portion 41 in the center, and is open at both ends. An outer peripheral flange 42 is provided at the proximal end portion of the diffuser portion 40 . The diffuser portion 40 is connected to the tip of the body portion 30 by joining the outer peripheral flanges 33 and 42 to each other so that the axes 30C and 40C are aligned with each other. In the hollow portion 41 of the diffuser portion 40, a pressurizing portion 41a and a discharge port portion 41b are sequentially formed from the proximal end to the distal end. The pressurizing portion 41a is a portion whose proximal end is continuous with the distal end of the mixing portion 31c and whose inner diameter gradually increases toward the distal end. The discharge port portion 41b is a portion having a constant inner diameter that is continuous with the tip of the pressurizing portion 41a. The refrigerant pipe line 1 between the condenser 5 is connected to the tip of the discharge port 41b. The pressurizing portion 41 a and the discharge port portion 41 b are provided on the axial center 40 C of the diffuser portion 40 .

Furthermore, the ejector 4 is provided with a chamber 50 around the diffuser section 40 . The chamber 50 is a closed space formed by attaching a cylindrical chamber structure 51 to the outer circumference of the diffuser section 40 . The chamber 50 communicates with the pressurizing section 41a through a communication hole 43 provided in the peripheral wall of the diffuser section 40, and communicates with the branch duct 7 through a pressure reducing duct 52. As shown in FIG. A plurality of communication holes 43 having the same shape are opened at equal intervals on the same circumference around the axis 40C of the diffuser part 40 at the portion located on the base end side of the pressure increasing part 41a. It is set up like this. Although not shown in the figure, in the present embodiment, a plurality of slit-shaped communication holes 43 are formed along the circumference. The decompression pipeline 52 is configured to have an inner diameter smaller than that of the branch pipeline 7 . In the present embodiment, the branch pipe 7 communicates with a portion slightly upstream of the portion connected to the suction portion 31 a of the ejector 4 . The communication destination of the decompression pipe line 52 with respect to the branch pipe line 7 may be anywhere as long as it is downstream of the expansion mechanism 9 and upstream of the ejector 4 .

In the cooling system configured as described above, the circulation pump 2 is driven to circulate and supply the refrigerant in the refrigerant pipe 1, and the hot water pipe 6 supplies waste hot water to the heating heat exchanger 3, and the cooling water pipe When the cooling water is supplied to the condenser 5 through the passage 8, the refrigerant that has passed through the heating heat exchanger 3 and has become a vapor phase is supplied to the ejector 4 as a driving fluid. In the ejector 4, the driving fluid is ejected from the injection port 21a of the nozzle portion 20 to the confluence portion 31b of the main body portion 30, so that the pressure of the confluence portion 31b is reduced. Refrigerant branched from to the branch pipe 7 is sequentially sucked into the suction portion 31a and the junction portion 31b as a suction fluid. The driving fluid and the suction fluid that have merged in the merging portion 31 b are mixed in the mixing portion 31 c , and then pressurized in the diffuser portion 40 and discharged to the condenser 5 . As a result, according to the cooling system described above, the refrigerant can be circulated and supplied without using a compressor. It becomes possible to absorb heat in the vessel 10 . Therefore, if the water to be cooled is supplied to the evaporator 10 through the water pipe 11 to be cooled, cold water can be obtained while suppressing running costs.

During this time, in the ejector 4, the suction pressure of the suction fluid acts on the chamber 50 through the decompression pipe line 52. Therefore, the peripheral wall portion of the pressurization portion 41a in the diffuser portion 40 is discharged through the communication hole 43 without driving an actuator such as a vacuum pump. pressure will decrease. Therefore, the refrigerant passing through the pressurizing portion 41a is sucked into the chamber 50, and boundary layer separation is suppressed in the diffuser portion 40, thereby preventing the generation of vortices and reducing the pump efficiency. become. Moreover, since the refrigerant sucked into the chamber 50 is supplied again to the suction space 32 of the ejector 4, there is no risk of leakage of the refrigerant to the outside.

In the above-described embodiment, the decompression pipeline 52 is connected to the branch pipeline 7, but the present invention is not necessarily limited to this. The pipe line 52 ′ may be connected to the hollow portion 31 of the body portion 30 so as to communicate therewith. In this case, it is preferable that the decompression pipe line 52 is connected to the body portion 30 on the upstream side of the tip of the nozzle portion 20, that is, connected to the suction portion 31a. In addition, in the modification of FIG. 3, the same code|symbol is attached|subjected about the structure similar to embodiment.

Further, as the communication holes 43, a plurality of holes having the same shape are provided on the same circumference around the axis 40C of the diffuser portion 40 so as to open at equal intervals. A communication hole 43 may be provided on the circumference.

Furthermore, in the above-described embodiment, since the axis 7C of the branch duct 7 is twisted with respect to the axis 30C of the main body 30, suction into the suction space 32 through the branch duct 7 is performed. The suctioned fluid reaches the opposite side along the peripheral surface of the nozzle portion 20 without colliding with the nozzle portion 20, and the flow in the suction space 32 can be evenly distributed. However, the invention is not necessarily so limited.

REFERENCE SIGNS LIST 1 refrigerant pipe 2 circulation pump 3 heating heat exchanger 4 ejector 5 condenser 7 branch pipe 9 expansion mechanism 10 evaporator 20 nozzle portion 30 body portion 40 diffuser portion 40C axial center 41 hollow portion 43 communicating hole 50 chamber 52.52 ′ decompression line

Claims (3)

An ejector that mixes a driving fluid ejected from a nozzle portion and a sucked fluid that is sucked as the driving fluid is ejected, and then pressurizes and ejects the fluid in a diffuser portion,
a chamber provided around the diffuser section and communicating with a hollow portion of the diffuser section through a communication hole provided in a peripheral wall of the diffuser section;
a decompression path that is provided to communicate with the interior of the chamber and causes the aspiration pressure of the aspiration fluid to act on the interior of the chamber ;
a main body provided to cover the periphery of the nozzle, having a downstream end continuous to the diffuser, and supplied with the suction fluid between itself and the nozzle;
with
The ejector , wherein the decompression path is connected to a portion of the main body portion upstream of a tip of the nozzle portion . 2. The ejector according to claim 1, wherein the communication holes are formed so as to have a rotationally symmetrical shape on the same circumference around the axis of the diffuser portion. 3. The ejector according to claim 2, wherein a plurality of said communication holes having the same shape are opened at regular intervals.

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