JP3898411B2 - Cross-flow fan design method and air conditioner - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a once-through fan that constitutes an air conditioner or the like, and more particularly to a once-through fan that improves its flow characteristics and flow instability to improve fan efficiency.
[0002]
[Prior art]
FIG. 9 is a configuration diagram showing a configuration of a general air conditioner.
In FIG. 9, the air conditioner mainly includes an indoor unit 100 arranged indoors, an outdoor unit 200 arranged outdoor, and a pipe 300 connecting the indoor unit 100 and the outdoor unit 200. The indoor unit 100 includes a once-through impeller 101 and an indoor heat exchanger 102. The outdoor unit 200 includes a blower 201, an outdoor heat exchanger 202, a four-way valve 203, a compressor 204, and an expansion valve 205.
[0003]
Next, the operation in the case of performing the heating operation will be described.
First, the refrigerant is adiabatically compressed by the compressor 204 and becomes high temperature. Thereafter, the high-temperature refrigerant is conveyed to the indoor heat exchanger 102 through the four-way valve 203. Since the room temperature is lower than the temperature of the refrigerant, the refrigerant releases heat in the indoor heat exchanger 102, and the cross-flow impeller 101 rotates, whereby hot air is released into the room. Next, the refrigerant cooled by the indoor heat exchanger 102 is adiabatically expanded by the expansion valve 205, and the temperature of the refrigerant becomes lower than the outside air temperature. Thereafter, the outdoor heat exchanger 202 absorbs heat from the outside air.
[0004]
In such indoor units, cross-flow blowers using cross-flow impellers are widely used. The efficiency improvement is from an energy-saving standpoint, low noise is from a comfort standpoint, and flow stability is from a product quality standpoint. The importance is increasing.
[0005]
In particular, recently, HCHF, which has been used as a refrigerant for air conditioners until now, has destroyed its ozone layer and its use has been restricted, and R410A, R407C, and the like have been used as new refrigerants. However, since R410A and R407C are high-pressure refrigerants, the amount of electric power used in the operation of the compressor is increased as compared with the prior art. And since there is a need to reduce the amount of electric power somewhere, the demand for improving the efficiency of the once-through fan has increased more than before.
[0006]
[Problems to be solved by the invention]
However, the design method of this once-through blower has not been well-established because the theoretical verification of the flow has not been made so much, so it has been characterized by trial and error methods corresponding to individual products. There has been no significant improvement.
[0007]
As a conventional method, for example, as shown in Japanese Patent Laid-Open No. 7-305695, the position of the stabilizer is substantially orthogonal to a line passing through the center of the once-through impeller from the lower portion in front of the once-through impeller. In addition, there are some which suppress the decrease in the discharge air volume and noise by making the scroll casing into two arcs so as to be optimal with respect to the stabilizer position.
[0008]
Further, as shown in Japanese Patent Application Laid-Open No. 61-118597, some scroll casings have a logarithmic linear shape, and their enlargement ratios are sequentially reduced to optimize and improve performance.
However, in the method described in Japanese Patent Laid-Open No. 7-305695, only the suction side shape and the blowout portion shape of the once-through impeller are changed in order to achieve efficiency improvement, noise reduction, and stable flow. The original phenomenon control of the flow produced by the once-through impeller was not performed. Moreover, in the method described in Japanese Patent Application Laid-Open No. 61-118597, the correlation with the theoretical verification of the flow produced by the once-through impeller is unclear, leaving some incomplete points in the formation of the optimum shape. There was a problem that the noise characteristics could not be improved drastically, and the design was trial and error for each product and the quality was lowered.
[0009]
The present invention has been made to solve the above-described problems, and the shape of the scroll casing is changed to the wind speed and the inflow angle of the wind flowing from the inside of the once-through impeller to the wing portion. Therefore, it is to provide a once-through fan that can improve efficiency and reduce noise.
[0010]
[Means for Solving the Problems]
In the once-through fan according to the present invention, the once- through impeller is provided in the scroll casing, and the outlet fan is provided on the extension line of the scroll casing. When the distance between the center of the cross-flow impeller and the end of the inflow side is r 0 , the shape can be expressed by the equation r = r 0 × exp (n L × θ), and the value of n L is , So that at least one of the magnitude of the inflow velocity of the wind flowing from the inner peripheral portion of the cross-flow impeller at the angle θ into the outer peripheral portion of the blade and the magnitude of the inflow angle of the wind increases. did.
[0011]
Further, the scroll casing has a maximum value of the enlargement ratio between the scroll casing inflow end and the bottom of the blowout flow.
[0012]
Furthermore, in the range of θ approximately 0 ° ≦ θ ≦ 360 ° × 3 / n (n: number of blades of the once- through impeller), n L = 0 was set.
[0013]
Furthermore, air with a compressor, a first heat exchanger connected to said compressor, and an outdoor unit having a four-way valve, the indoor unit having a second heat exchanger and transmural flow fan In the conditioner, the cross-flow fan is designed by any one of claims 1 to 3.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
1 is a cross-sectional view of an indoor unit of an air conditioner incorporating a cross-flow fan according to Embodiment 1 of the present invention.
In FIG. 1, 1 is a main body, and 2 is a panel mounted from the front of the main body. The panel 2 is provided with a front grill 3 that forms an intake port for air sucked from the front surface, a suction port 4 for taking in air from the upper portion, and a blowout port 5 for blowing air from the lower portion. Further, the main body 1 has a heat exchanger 6, a drain pan 7 that receives drain water that adheres and drops on the heat exchanger 6, and heat exchange between the refrigerant flowing in the heat exchanger 6 and room air. A cross-flow impeller 8 that generates an air flow necessary for the operation is disposed. The once-through impeller 8 rotates clockwise.
[0017]
Further, the back surface of the main body 1 also serves as a scroll casing 9, and a blowout lower guide portion 10 is disposed on the lower extension line thereof. A part of the drain pan 7 serves as both the stabilizer 11 and the outlet flow upper guide portion 12. Reference numeral 13 denotes an outlet duct, which includes an outlet flow upper guide portion 12 and an outlet flow lower guide portion 10. The once-through fan is constituted by a once-through impeller 8, a scroll casing 9, a stabilizer 11, and an outlet duct 13.
[0018]
The scroll casing 9 has a logarithmic spiral line, that is, an arbitrary distance r from the center 14 of the once-through impeller 8 to the scroll casing 9.
[0019]
r = r ₀ × exp (n _L × θ) (Equation 1)
[0020]
It has a shape represented by Here, r ₀ is the distance between the inflow side end 15 of the scroll casing 9 and the center 14 of the cross-flow impeller 8, n _L is the amount of spread of the scroll casing 9, and is generally called the enlargement factor. Naturally, the extent of spread increases as the value of the enlargement factor n _L increases. Further, θ is a spread angle with reference to the inflow side end 15 of the scroll casing 9.
[0021]
Next, the air flow in the vicinity of the once-through fan in the indoor unit of FIG. 1 will be described.
FIG. 2 is a diagram showing an air flow state in the vicinity of the once-through fan in the configuration of FIG. First, when the once-through impeller 8 rotates, the suction flow that has passed through the heat exchanger 6 through the front grill 3 and the upper suction port 4 at the boundary of the stabilizer 11 flows into and passes through the inside of the once-through impeller 8. It flows into the blowing duct 13 and becomes a blowing flow. At this time, it is considered that a forced vortex flow 16 is formed with a center 17 in the vicinity of the stabilizer 11 in the once-through impeller 8. The forced vortex flow 16 is theoretically formed only inside the rotating actuator that creates the vortex flow. In the case of the cross-flow impeller 8 as shown in FIG. In particular, the blade inner side 18a corresponds. A plurality of wings 18 are arranged at random intervals so that one end thereof faces outward.
[0022]
On the other hand, the blow-out flow flowing into the blow-out duct 13 is blown out of the impeller as a flow formed on a logarithmic line in accordance with a general forward-wing centrifugal impeller theory. At this time, as an important physical quantity for determining the flow shape of the logarithmic line, the magnitude and direction of the velocity flowing into the wing portion 18b outside the line formed by connecting the wing inner sides 18a of each wing (hereinafter referred to as the following) "Angle"). In the case of a general forward-wing centrifugal impeller, this physical quantity is almost constant in any blade suction portion, and therefore, the flow shape of a logarithmic line can be uniquely determined.
[0023]
However, in the case of the once-through impeller 8 as shown in FIG. 1, the physical quantity that determines the flow shape of the logarithmic line is dominated by the forced vortex flow 16, and therefore cannot be uniquely determined by the characteristics of the vortex flow. FIG. 3 is a graph showing the relationship between the vortex radius from the vortex center 17 of the forced vortex flow 16 formed in the once-through impeller 8 and the vortex circumferential speed at the radius point. FIG. 4 is a graph showing a simplified relationship between the inflow angle and the spread angle θ when the forced vortex flow 16 flows into the blade portion 18 b of the once-through impeller 8. The inflow angle is an angle when the forced vortex flow 16 in the once-through impeller 8 flows in from the blade inner side 18a, and 0 ° when facing the radially outer side. The case of flowing in from the current direction is represented as a positive value, and the case of flowing in the opposite direction, that is, the direction of rotation, is represented as a negative value.
[0024]
As can be seen from these graphs, it can be seen that the magnitude and angle of the velocity flowing into the blade portion 18b of the once-through impeller 8 are variously changed depending on the spread angle θ. That is, the important physical quantity that determines the flow shape of the logarithmic line shows various values in each blade suction portion, so the flow shape of the logarithmic line cannot be uniquely determined, and the flow generated here Therefore, the loss of the flow blown out of the once-through impeller 8 can be reduced. Therefore, the enlargement ratio n _L at the angle θ can be reduced to the wing portion 18b of the once-through impeller 8 at that angle. It is necessary to determine the speed according to the speed of the wind flowing in from the inside or the angle of inflow of the wind flowing into the wing portion 18b of the cross-flow impeller 8 from the inside.
[0025]
That is, the enlargement ratio n _L is increased as the speed of the wind flowing into the blade portion 18b of the once-through impeller 8 from the inside increases, and the enlargement ratio n _L is decreased as the wind speed is decreased. The design is such that the enlargement factor n _L is increased as the inflow angle of the wind flowing into the wing portion 18b from the inside increases, and the enlargement factor n _L is reduced as the wind inflow angle is reduced.
[0026]
Thus, the magnitude of the enlargement ratio n _L at the angle θ is determined based on the velocity of the wind flowing into the wing portion 18b of the once-through impeller 8 from the inside and the inflow of wind flowing into the wing portion 18b of the once-through impeller 8 from the inside. By determining according to the angle, it is possible to reduce the loss of the flow blown from the once-through impeller 8, and it is possible to obtain a high-quality once-through fan corresponding to each product with high efficiency and low noise. .
[0027]
Furthermore, when the inflow velocity and angle into the wing portion 18b, that is, the velocity vector are comprehensively determined from FIGS. 3 and 4, the relationship between the enlargement ratio n _L and the spread angle θ is as shown in FIG. Convex, a relationship having one maximum value, that is, a shape in which the most expanded place is formed in the middle of the scroll casing 9 from the scroll casing inflow side end portion 15 to the outlet flow lower side guide portion 10 In Fig. 1, it is found that the flow is closest to the state of the flow blown out from the once-through impeller 8 and is very good.
[0028]
Therefore, the shape of the scroll casing 9 is determined to be n _L so that the most expanded place is formed in the middle of the scroll casing 9 from the scroll casing inflow side end portion 15 to the outlet flow lower side guide portion 10. Thereby, the loss of the flow blown from the once-through impeller 8 can be further reduced.
[0029]
Moreover, as a material of the once-through impeller 8, by using a magnesium alloy, the effect of weight reduction and recyclability improvement is acquired.
[0030]
Embodiment 2. FIG.
FIG. 6 shows a state of air flow in the indoor unit of the air conditioner shown in FIG. 1, and further shows details of the flow in the wing portion 18b in FIG. Further, FIG. 7 is a diagram showing an air flow state in the vicinity of the wing portion at 0 ° ≦ θ ≦ 360 ° × 3 / n (n: the number of blades of the once-through impeller 8). The coordinate system in FIG. 6 is the same coordinate system as that of the rotating once-through impeller 8. As can be seen from FIG. 6, the spread angle θ substantially defines the blade pitch of three blades of the cross-flow impeller 8 from the inflow side end 15 of the scroll casing 9 toward the downstream side of the scroll casing 9. In the range of ° ≦ θ ≦ 360 ° × 3 / n, the circulation flow 19 changes its direction between the blades 18, and the flow blown out from the once-through impeller 8 does not exist.
[0031]
Therefore, in this portion, the air is blown out by the vortex 20 or the sag 21 generated by the useless space between the cross-flow impeller 8 and the scroll casing 9 or the reverse flow 22 directed in the direction opposite to the rotation of the cross-flow impeller 8. Flow loss occurs.
From this, it is substantially equivalent to three blade numbers of the cross-flow impeller 8 from the scroll casing inflow side edge part 15 toward the downstream side of the scroll casing 9, and in Equation 1, 0 ° ≦ θ ≦ 360 ° × 3 / n: the n _L of (n wing number of once-through impeller 8) to zero, by an equal arc shape to prevent the loss of blowing stream can be further obtained a good flow blower efficiency. 8 is a cross-sectional view of an indoor unit of an air conditioner incorporating a once-through blower. In FIG. 1, among the scroll casings, 0 ° ≦ θ ≦ 360 ° × 3 / n (n: once-through impeller 8). The portion indicated by the number of blades) is formed in an equal arc shape.
[0032]
【The invention's effect】
Thus, in this invention, it becomes possible to reduce the loss of the flow blown from the once-through impeller, and it is possible to obtain a high-quality once-through fan corresponding to each product with high efficiency and low noise.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an indoor unit using a cross-flow fan according to Embodiment 1 of the present invention.
FIG. 2 is a diagram showing an air flow in the vicinity of the once-through fan of the indoor unit according to Embodiment 1 of the present invention.
FIG. 3 is a diagram showing a relationship between a vortex radius and a peripheral velocity in a vortex circumferential direction.
FIG. 4 is a diagram illustrating a relationship between a spread angle and an inflow angle.
FIG. 5 is a diagram showing a relationship between an enlargement ratio and a spread angle according to Embodiment 3 of the present invention.
FIG. 6 is a diagram showing the air flow in the vicinity of the wing of the once-through impeller.
FIG. 7 is a diagram showing a state of air flow.
FIG. 8 is a cross-sectional view of an indoor unit using a once-through fan in Embodiment 2 of the present invention.
FIG. 9 is a diagram showing a configuration of a conventional air conditioner.
[Explanation of symbols]
1 Body, 2 Panel, 3 Front grille, 4 Air inlet,
5 outlet, 6 heat exchanger, 7 drain pan,
8 once-through impeller, 9 scroll casing,
10 Outflow downstream guide, 11 Stabilizer,
12 Blowing flow upper side guide part, 13 Blowing duct,
14 Center of once-through impeller, 15 Inlet side end,
16 Forced vortex flow, 17 Center of forced vortex flow,
18 Wing of a once-through impeller, 18a Inner wing, 18b Wing,
19 Circulating flow, 20 Vortex, 21 Swelling, 22 Backflow

Claims (4)

In a once-through fan having a once-through impeller in a scroll casing and having a blow-out duct on an extension line of the scroll casing,
The scroll casing has an equation r = r0 × exp (nL × θ) where θ = 0 ° is the inflow side end of the scroll casing and r0 is the distance between the center of the cross-flow impeller and the inflow side end. ), And the value of nL is the value of the once-through impeller at the angle θ.
A design method for a cross-flow blower , wherein at least one of a magnitude of an inflow velocity of a wind flowing from an inner peripheral portion of a blade into an outer peripheral portion of the blade or a magnitude of an inflow angle of the wind increases. The design method for a cross-flow fan according to claim 1, wherein the scroll casing has a maximum value of an enlargement ratio between the scroll casing inflow end and the bottom of the blowout flow. 3. The once-through flow according to claim 1, wherein nL = 0 in the range of θ approximately 0 ° ≦ θ ≦ 360 ° × 3 / n (n: number of blades of the once-through impeller). How to design a blower. A compressor, wherein a first heat exchanger connected to the compressor, and an outdoor unit having a four-way valve, an air conditioner and a second heat exchanger and transmural flow indoor unit having an air blower In addition, the said cross-flow fan was designed by the method in any one of Claims 1-3, The air conditioner characterized by the above-mentioned.

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