Refrigerant distributor, heat exchanger, and refrigeration cycle device

Abstract

A refrigerant distributor (31) comprises a mixing section (51) having a cylindrical shape. An inlet (510) into which a refrigerant flows is formed at an upstream end (51a) of the mixing section (51). A plurality of outlets (511) through which the refrigerant flows out are formed at the downstream end (51b) of the mixing section on the opposite side to the upstream end (51a) thereof. A recess facing the inlet (510) is formed at the downstream end (51b) of the mixing section (51). 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 a side wall (51d) of the mixing section (51), diffuses the refrigerant in the circumferential direction of the downstream end (51b), and then delivers the refrigerant from the outlets (511).

Description

Technical Field

[0001] The present disclosure relates to a refrigerant distributor, a heat exchanger, and a refrigeration cycle apparatus.

Background Art

[0002] An air conditioner includes a refrigerant circuit that circulates a refrigerant. The refrigerant circuit includes a compressor that compresses the refrigerant, an expansion device that expands the refrigerant, an indoor heat exchanger that exchanges heat between the refrigerant and indoor air, an outdoor heat exchanger that exchanges heat between the refrigerant and outdoor air, and refrigerant pipes that connect these in a loop. When the air conditioner is in cooling operation, the indoor heat exchanger functions as an evaporator that absorbs heat from the outside and evaporates the refrigerant. When the air conditioner is in heating operation, the outdoor heat exchanger functions as an evaporator.

[0003] The refrigerant circulating in the refrigerant circuit is sent out from the expansion device in a gas-liquid two-phase state and flows into the evaporator, that is, the indoor heat exchanger or the outdoor heat exchanger, and exchanges heat with air while flowing through the heat transfer pipes built in the evaporator. When the gas-liquid two-phase refrigerant exchanges heat with air, the liquid-phase refrigerant contained in this refrigerant evaporates and changes into a gas-phase refrigerant. As a result, the refrigerant changes from a gas-liquid two-phase state to a gas-phase single-phase state while flowing through the heat transfer pipes. That is, the refrigerant flows through a part of the section of the heat transfer pipe in a gas-liquid two-phase state and the remaining section of the heat transfer pipe in a gas-phase single-phase state.

[0004] When a pressure loss of the refrigerant occurs inside the heat transfer pipe, the heat exchange efficiency of the evaporator decreases. For this reason, the indoor heat exchanger and the outdoor heat exchanger that function as evaporators include a plurality of heat transfer pipes and a refrigerant distributor that distributes the refrigerant to these heat transfer pipes, and by distributing the refrigerant to each heat transfer pipe, the flow rate of the refrigerant inside each heat transfer pipe is reduced, and the pressure loss of the refrigerant is reduced.

[0005] When the refrigerant pipe inside the evaporator has a curved portion located upstream of the refrigerant distributor, centrifugal force is applied when the refrigerant in the gas-liquid two-phase state passes through the curved portion, and the liquid-phase refrigerant contained in this refrigerant flows into the refrigerant distributor in a biased state. In this case, variations occur in the amount of liquid-phase refrigerant distributed to each heat transfer tube by the refrigerant distributor. The shorter the length of the heat transfer tube with a smaller amount of distributed liquid-phase refrigerant, the longer the section where the refrigerant flows in the gas-phase single-phase state. Since the heat transfer coefficient of the refrigerant in the gas-phase single-phase state is extremely small compared to that of the refrigerant in the gas-liquid two-phase state, the heat exchange efficiency in the section where the refrigerant flows in the gas-phase single-phase state inside the heat transfer tube is extremely low compared to the heat exchange efficiency in the section where the refrigerant flows in the gas-liquid two-phase state. For this reason, the longer the section where the refrigerant flows in the gas-phase single-phase state in the heat transfer tube, the lower the heat exchange efficiency. Therefore, when variations occur in the length of the section where the refrigerant flows in the gas-phase single-phase state in each heat transfer tube, the heat exchange efficiency of the evaporator decreases.

[0006] In view of such circumstances, the refrigerant distributor described in Patent Document 1 includes an inlet pipe into which the refrigerant in the gas-liquid two-phase state flows, a branch space that mixes and branches the refrigerant in the gas-liquid two-phase state flowing in from the inlet pipe, a plurality of outlet pipes through which the refrigerant in the gas-liquid two-phase state branched in the branch space flows out, an inflow passage connecting the inlet pipe and the branch space, and a plurality of outflow passages respectively connecting the branch space and the plurality of outlet pipes. The branch space is provided with a mixing portion having a concave shape formed at a position facing the inflow passage. Let the inner diameter of the inflow passage be Da [mm], the flow cross-sectional area of the inflow passage be Ai [mm 2 , the inner diameter of the mixing portion be Db [mm], the area of the branch space be Av [mm 2 , the height of the branch space be Hv [mm], the area of the circumscribed circle of the outflow passage be Apo [mm 2 , and the area of the inscribed circle of the outflow passage be Api [mm2]. Then, Ai / (π×Da×Hv)≧0.5, Av / (Apo - Api)≦2.0, and Db / Da≦1.0. With such a configuration, the refrigerant distributor described in Patent Document 1 reduces the variations in the amount of refrigerant sent from each outlet pipe to the heat transfer tubes.

Prior Art Documents

Patent Documents

[0007] Patent Document 1 Japanese Patent Application Laid-Open No. 2014-81149 Summary of the Invention Problems to be Solved by the Invention

[0008] However, depending on the flow rate, type, and temperature of the refrigerant flowing into the refrigerant distributor described in Patent Document 1, it may not be possible to reduce the variation in the amount of refrigerant distributed to each heat transfer tube.

[0009] The present disclosure has been made in view of the above circumstances, and an object thereof is to reduce the variation in the amount of refrigerant distributed to each heat transfer tube regardless of the flow rate, type, and temperature of the refrigerant when distributing the refrigerant to a plurality of heat transfer tubes. Means for Solving the Problems

[0010] To achieve the above object, the refrigerant distributor according to the present disclosure includes a mixing portion having a cylindrical shape. An inlet through which refrigerant flows is formed at a first end portion of the mixing portion. A plurality of outlets through which refrigerant flows out are formed at a second end portion of the mixing portion, which is opposite to the first end portion. A recess facing the inlet is formed at the second end portion of the mixing portion. The mixing portion guides the refrigerant flowing in from the inlet to flow along the first end portion of the mixing portion and the side wall of the mixing portion, diffuses in the circumferential direction of the second end portion, and then sends it out from the outlets. Into the depression the refrigerant flowing in The gaseous refrigerant contained therein and By guiding it so as to collide with the liquid-phase refrigerant contained in the refrigerant flowing in from the inlet, the liquid-phase refrigerant is pressed against the first end of the mixing section. sends it out from the outlets after diffusing in the circumferential direction of the second end portion by guiding it to flow along the first end portion of the mixing portion and the side wall of the mixing portion. The refrigerant distributor further includes a guiding section disposed at the second end of the mixing section. The guiding section guides the gaseous refrigerant that has been guided into the mixing section and collided with the liquid-phase refrigerant from the second end of the mixing section to the first end of the mixing section. Effects of the Invention

[0011] According to the above configuration, regardless of the flow rate, type, and temperature of the refrigerant in the gas-liquid two-phase state flowing into the mixing section, the variation in the amount of refrigerant sent out from each outlet becomes small. As a result, when heat transfer tubes are connected to each outlet, the variation in the amount of refrigerant flowing into the heat transfer tubes from each outlet becomes small regardless of the flow rate, type, and temperature of the refrigerant. That is, according to the above configuration, when distributing the refrigerant to a plurality of heat transfer tubes, it is possible to reduce the variation in the amount of refrigerant distributed to each heat transfer tube regardless of the flow rate, type, and temperature of the refrigerant.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

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Figure 8

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Figure 10

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Figure 15

Figure 16

Mode for Carrying Out the Invention

[0013] Hereinafter, a refrigerant distributor, a heat exchanger, and a refrigeration cycle apparatus according to an 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

[0014] (Embodiment 1) The air conditioner 100 shown in Fig. 1 conditions the air inside an air-conditioning target space 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.

[0015] The refrigerant circuit 10 includes a compressor 1 that compresses the refrigerant, an expansion device 2 that expands the refrigerant and switches the circulation direction of the refrigerant inside the refrigerant circuit 10, an indoor heat exchanger 3 built into an indoor unit 6 installed inside the air-conditioning target space, which exchanges heat between the refrigerant and the air inside the air-conditioning target space, an outdoor heat exchanger 4 built into an outdoor unit 7 installed outside the air-conditioning target space, which exchanges heat between the refrigerant and the air outside the air-conditioning target space, and a main refrigerant pipe 5 through which the refrigerant flows, connecting the compressor 1 to the outdoor heat exchanger 4 in a loop. The indoor heat exchanger 3 and the outdoor heat exchanger 4 are examples of heat exchangers.

[0016] 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 operations of the compressor 1, the expansion device 2, the indoor unit 6, and the outdoor unit 7 by transmitting control signals.

[0017] The throttling device 2 includes an expansion valve that expands the refrigerant and a four-way valve that switches the circulation direction of the refrigerant. The control device 20 controls the four-way valve of the throttling device 2 to switch the circulation direction of the refrigerant, 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 the 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, and the air inside the air-conditioned space is cooled. When the air conditioner 100 is in the 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.

[0018] FIG. 2 is a Mollier diagram showing the state of the refrigerant circulating in the refrigerant circuit 10. In FIG. 2, the horizontal axis represents the enthalpy of the refrigerant, and the vertical axis represents the pressure of the refrigerant. FIG. 2 shows a saturated liquid line MM and a saturated vapor line NN. The region where the enthalpy H of the refrigerant 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 enthalpy H of the refrigerant 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 enthalpy H of the refrigerant is equal to or greater than the saturated liquid line MM and equal to or less than the saturated vapor line NN is the region where the refrigerant is in a gas-liquid two-phase state.

[0019] In the cooling operation state, the refrigerant is first compressed by the compressor 1 and changes from a low-pressure gaseous refrigerant to a high-pressure gaseous refrigerant as shown in the path from point S to point T in Figure 2, and then flows into the outdoor heat exchanger 4. The refrigerant flowing into the outdoor heat exchanger 4 exchanges heat with the air outside the air-conditioned space to dissipate heat and is condensed, becoming a high-pressure liquid-phase refrigerant as shown in the path from point T to point U in Figure 2, and then flows into the throttling device 2. Then, the refrigerant is depressurized by being expanded by the expansion valve provided in the throttling device 2 and becomes a low-pressure gas-liquid two-phase state refrigerant as shown in the path from point U to point V in Figure 2, and then flows into the indoor heat exchanger 3. The refrigerant flowing into the indoor heat exchanger 3 exchanges heat with the air inside the air-conditioned space to absorb heat and evaporates, becoming a low-pressure gaseous refrigerant as shown in the path from point V to point S in Figure 2, and then flows into the compressor 1.

[0020] The indoor unit 6 includes a housing incorporating the indoor heat exchanger 3, a fan that blows air through the indoor heat exchanger 3, and a motor that drives the fan according to the control by the control device 20. The fan is rotationally driven by the motor to allow the air inside the air-conditioned space to flow into the housing. The indoor heat exchanger 3 causes the refrigerant to exchange heat with the air flowing into the housing. The fan is rotationally driven by the motor to send the air after heat exchange with the refrigerant back into the air-conditioned space. Thereby, the air inside the air-conditioned space is conditioned.

[0021] The outdoor unit 7 includes a housing incorporating the outdoor heat exchanger 4, a fan that blows air through the outdoor heat exchanger 4, and a motor that drives the fan according to the control by the control device 20. The fan is rotationally driven by the motor to allow the air outside the air-conditioned space to flow into the housing. The outdoor heat exchanger 4 causes the refrigerant to exchange heat with the air flowing into the housing. The fan is rotationally driven by the motor to send the air after heat exchange with the refrigerant outside the air-conditioned space.

[0022] 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 include eight heat transfer tubes 30, a pair of refrigerant distributors 31 connected to both ends of each heat transfer tube 30 for distributing refrigerant to each heat transfer tube 30, and a pair of internal refrigerant pipes 32 connecting each refrigerant distributor 31 and 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 out 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 radiation fins, and the refrigerant distributed to each heat transfer tube 30 by the refrigerant distributor 31 exchanges heat with air through these heat radiation fins while flowing through each heat transfer tube 30.

[0023] When the indoor heat exchanger 3 and the outdoor heat exchanger 4 function as evaporators, the gas-liquid two-phase refrigerant sent out 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 air while flowing through each heat transfer tube 30. By distributing the refrigerant to a plurality of 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 gas-liquid two-phase refrigerant exchanges heat with air, the liquid-phase refrigerant contained in this refrigerant evaporates and changes into a gas-phase refrigerant. As a result, the refrigerant changes from the gas-liquid two-phase state to the gas-phase single-phase state with an extremely small heat transfer rate during the process of flowing through the heat transfer tube. After the refrigerant flowing through each heat transfer tube 30 changes to the gas-phase single-phase state, it merges in the refrigerant distributor 31 connected to the compressor 1, and is sent from this refrigerant distributor 31 to the compressor 1.

[0024] By reducing the variation in the length of the section where the refrigerant in each heat transfer tube 30 flows in a gas-phase single-phase state, that is, the section with low heat exchange efficiency, the heat exchange efficiency of the evaporator can be improved. The variation in the length of the section where the refrigerant flows in a gas-phase single-phase state can be reduced by reducing the variation in the heat load of the refrigerant in each heat transfer tube 30. The heat 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 of the heat transfer tube 30 and the enthalpy of the refrigerant at the outlet. Therefore, the variation in the heat 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 according to the present embodiment reduces the variation in the heat load of the refrigerant in each heat transfer tube 30 by reducing the variation in the mass flow rate of the refrigerant flowing through each heat transfer tube 30, reduces the variation in the length of the section where the refrigerant in each heat transfer tube 30 flows in a gas-phase single-phase state, and improves the heat exchange efficiency of the evaporator.

[0025] FIG. 4(A) is a perspective view of an internal refrigerant pipe 32 connected to a throttle device 2 via a main refrigerant pipe 5 and a refrigerant distributor 31 connected to the internal refrigerant pipe 32. The internal refrigerant pipe 32 includes a connection portion 39 connected to the main refrigerant pipe 5 and having a linear shape, a curved portion 40 located downstream of the connection portion 39 and having a U shape, and a straight pipe portion 41 located downstream of the curved portion 40 and having a linear shape. The downstream end of the straight pipe portion 41 is connected to the refrigerant distributor 31. The gas-liquid two-phase refrigerant flowing into the internal refrigerant pipe 32 from the throttle device 2 via the main refrigerant pipe 5 passes through the connection portion 39, the curved portion 40, and the straight pipe portion 41 in this order and flows into the refrigerant distributor 31. FIG. 4(B) is a cross-sectional view of the internal refrigerant pipe 32 cut along a cross-section perpendicular to the extending direction of the connection portion 39 and the straight pipe portion 41. For ease of understanding, an XYZ orthogonal coordinate system shown in FIGS. 4(A) and 4(B) is set. The Z axis is set parallel to the gravitational direction 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.

[0026] When the refrigerant in a gas-liquid two-phase state flows through the internal refrigerant pipe 32, the gaseous-phase refrigerant contained in this refrigerant flows through the central part of the internal refrigerant pipe 32, and the liquid-phase refrigerant contained in this refrigerant flows along the inner wall of the internal refrigerant pipe 32 in a liquid film state. However, since there is a difference between the density of the gaseous-phase refrigerant and the density of the liquid-phase refrigerant, there is a difference between the flow velocity of the gaseous-phase refrigerant and the flow velocity of the liquid-phase refrigerant. As a result, at the interface between the gaseous-phase refrigerant and the liquid-phase refrigerant, a shear stress acts on the liquid-phase refrigerant in the liquid film state, and liquid droplets are torn off from the liquid film and scattered. For this reason, in the central part of the internal refrigerant pipe 32, there are a large number of liquid-phase refrigerants in the form of liquid droplets together with the gaseous-phase refrigerant.

[0027] When the refrigerant in a gas-liquid two-phase state flows through the curved part 40, a 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. That is, the thickness of the liquid film of the liquid-phase refrigerant adhering to the inner wall of the internal refrigerant pipe 32 becomes non-uniform. As a result, the refrigerant that has passed through the curved part 40 flows into the straight pipe part 41 in a state where the liquid-phase refrigerant contained in the refrigerant is biased in the +X-axis direction.

[0028] When the refrigerant flows through the straight pipe part 41, a secondary flow is generated to make 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 becomes smaller. If the straight pipe part 41 is sufficiently long, the bias of the liquid-phase refrigerant is eliminated while the refrigerant flows through the straight pipe part 41, and the refrigerant flows into the refrigerant distributor 31 in a state where the liquid-phase refrigerant is not biased. However, in the present embodiment, due to structural constraints, the straight pipe part 41 is shorter than the length required to eliminate the bias of the liquid-phase refrigerant. For this reason, the refrigerant flows into the refrigerant distributor 31 in a state where the liquid-phase refrigerant is biased in the +X-axis direction.

[0029] As shown in Fig. 5(A), the refrigerant distributor 31 includes an inlet pipe 50 connected to the internal refrigerant pipe 32, a mixing part 51 connected to the inlet pipe 50, a plurality of outlet pipes 52 connected to the mixing part 51, and a recessed part 53 connected to the mixing part 51.

[0030] The upstream end of the inlet pipe 50 is connected to the straight pipe portion 41 of the internal refrigerant pipe 32, and the downstream end of the inlet pipe 50 is connected to the inlet 510 formed at the upstream end 51a of the mixing portion 51. That is, the internal refrigerant pipe 32 is connected to the inlet 510 via the inlet pipe 50. The upstream end 51a of the mixing portion 51 is an example of the first end. 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 portion 41 of the internal refrigerant pipe 32. The refrigerant in the gas-liquid two-phase state sent out from the throttling device 2 flows into the inlet pipe 50 via the main refrigerant pipe 5 and the internal refrigerant pipe 32. The refrigerant flowing from the internal refrigerant pipe 32 into the inlet pipe 50 flows into the mixing portion 51 from the inlet pipe 50 via the inlet 510.

[0031] The mixing portion 51 is hollow and has a cylindrical shape. An outlet pipe 52 and a recessed portion 53 are connected to the downstream end 51b of the mixing portion 51. The downstream end 51b of the mixing portion 51 is the end opposite to the upstream end 51a and is an example of the second end. The refrigerant distributor 31 includes eight outlet pipes 52 that are the same number as the number of heat transfer pipes 30, and these outlet pipes 52 are connected to the eight heat transfer pipes 30 described above. Each outlet pipe 52 is connected to a different heat transfer pipe 30. Specifically, the downstream end of each outlet pipe 52 is connected to the heat transfer pipe 30. The upstream end of each outlet pipe 52 is connected to any one of a plurality of outlets 511 formed at the downstream end 51b of the mixing portion 51. That is, each heat transfer pipe 30 is connected to each outlet 511 via each outlet pipe 52. The refrigerant flowing into the mixing portion 51 from the inlet pipe 50 is sent out from the mixing portion 51 to each outlet pipe 52 via each outlet 511. That is, the refrigerant flowing into the mixing portion 51 is distributed to each outlet pipe 52. The refrigerant flowing into each outlet pipe 52 from the mixing portion 51 is sent out from each outlet pipe 52 to the heat transfer pipe 30 connected to each outlet pipe 52. Thereby, the refrigerant in the gas-liquid two-phase state flowing into the refrigerant distributor 31 is distributed to each heat transfer pipe 30.

[0032] The space inside the recessed portion 53 corresponds to the recess formed in the mixing portion 51. The recessed portion 53 communicates with the mixing portion 51 through a circular opening 51c formed at the downstream end portion 51b of the mixing portion 51 and facing the inlet pipe 50 and the inlet port 510. That is, the space inside the recessed portion 53, which is the recess of the mixing portion 51, is formed at the downstream end portion 51b of the mixing portion 51 facing the inlet pipe 50 and the inlet port 510. The recessed portion 53 has a shape in which a hollow cone is continuously provided to a cylinder connected to the opening 51c of the mixing portion 51. A part of the refrigerant sent out from the inlet port 510 flows into the internal space of the recessed portion 53 and then flows from the recessed portion 53 into the mixing portion 51.

[0033] As described above, the refrigerant in the gas-liquid two-phase state flows into the refrigerant distributor 31 with the liquid-phase refrigerant contained in the refrigerant biased in the +X-axis direction. Therefore, if no countermeasures are taken, there will be variations in the amount of the liquid-phase refrigerant sent out from each outlet port 511 of the refrigerant distributor 31 through each outlet pipe 52. Specifically, as shown in FIG. 5(B), the positions of the respective outlet pipes 52 in the X-axis direction are different from each other. If no countermeasures are taken, the larger the X coordinate of the outlet pipe 52, the larger the amount of the liquid-phase refrigerant sent out. Hereinafter, the outlet pipe 52 with the largest X coordinate, which is the outlet pipe 52 with the largest amount of the liquid-phase refrigerant sent out when no countermeasures are taken, is referred to as the "reference outlet pipe 52a" to distinguish it from the other outlet pipes 52. However, when there is no need to distinguish between the reference outlet pipe 52a and the other outlet pipes 52, these are collectively simply referred to as the "outlet pipe 52".

[0034] In the present embodiment, the inner diameter of the inlet port 510 shown in FIG. 6 is Di [mm], the mass flow rate of the gas-liquid two-phase state refrigerant flowing from the internal refrigerant pipe 32 into the inlet pipe 50 is G [kg / h], the gas-phase density of this refrigerant is ρ g [kg / m 3 , the liquid-phase density of this refrigerant is ρ l [kg / m 3When this is the case, the height h [mm] of the mixing section 51 satisfies the following Equation 1. FIG. 6 is a cross-sectional view of the refrigerant distributor 31 cut along 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 vapor density ρ g of the refrigerant in the gas-liquid two-phase state is the density of the vapor-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 the present embodiment, the height h of the mixing section 51 was 2.5 [mm] or more and 4 [mm] or less. As will be described later, according to such a configuration, regardless of the flow rate, type, and temperature of the refrigerant in the gas-liquid two-phase state flowing into the inlet pipe 50, the variation in the amount of refrigerant sent out from each outlet 511 through each outlet pipe 52 can be reduced.

[0035]

Equation

[0036] Further, in the present embodiment, the diameter Dc [mm] of the recess formed in the mixing section 51, which is the internal space of the recess section 53, is larger than the inner diameter Di of the inlet 510. Note that 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 section 53 is connected. As will be described later, according to such a configuration, the variation in the amount of refrigerant sent out from each outlet 511 through each outlet pipe 52 can be reduced.

[0037] In addition, in the present embodiment, a first distance Li [mm], which is the distance between the depression formed in the mixing section 51 and the axis QQ of the outlet 511, is greater than a 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 the present 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 so as to be separated from the recessed section 53 toward the radially outer side of the downstream end 51b of the mixing section 51. Specifically, the eight outlet pipes 52 and the outlets 511 to which the respective outlet pipes 52 are connected are arranged on the circumference of a circle centered on the axis of the recessed section 53. Also, the axis of the mixing section 51 is the same as the axis of the depression. Therefore, the distances between the axis QQ of each outlet 511 and the depression are the same as each other, and the distances between the axis QQ of each outlet 511 and the side wall 51d of the mixing section 51 are the same as each other. That is, the first distance Li and the second distance Lo of each outlet 511 are the same as each other.

[0038] According to such a configuration, the processing when manufacturing the refrigerant distributor 31 can be facilitated, and the manufacturing cost can be suppressed. Specifically, as an example, when the material of the refrigerant distributor 31 is a metal material such as copper or aluminum, the depression in the mixing section 51 is formed by cutting this metal material with a drill. At this time, the shorter the distance between the outlet 511 and the depression in the mixing section 51, the smaller the amount of metal material existing between the outlet 511 and the depression in the mixing section 51, the more difficult the processing becomes, and the manufacturing cost increases. In the present embodiment, since the first distance Li is greater than the second distance Lo, the distance between the outlet 511 and the depression in the mixing section 51 is sufficiently large, the processing becomes easy, and the manufacturing cost is suppressed. Note that the material of the refrigerant distributor 31 is not limited to a metal material, and may be any material such as resin. Also, the manufacturing method of the refrigerant distributor 31 is not limited to the method described above, and may be any method such as press molding or integral molding.

[0039] The following describes the distribution of the refrigerant by the refrigerant distributor 31, using the result of the simulation of the flow of the refrigerant inside the refrigerant distributor 31, which was performed using a computer. In this simulation, it is assumed that the refrigerant in the gas-liquid two-phase state flows into the inlet pipe 50 with the liquid-phase refrigerant contained in this refrigerant being biased in the +X axis direction. This simulation was performed under the conditions that the diameter Dc of the recess in 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]. In the simulation, R290, that is, propane, was used as the refrigerant unless otherwise specified. The temperature of the refrigerant in the simulation is 10 [°C].

[0040] FIG. 7 shows the relationship between the height h of the mixing section 51 and the liquid-phase refrigerant distribution ratio 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], which was obtained by simulation. The liquid-phase refrigerant distribution ratio of the reference outlet pipe 52a is the ratio of the mass flow rate of the liquid-phase refrigerant sent out from the outlet 511 connected to the reference outlet pipe 52a through the reference outlet pipe 52a to the total mass flow rate of the liquid-phase refrigerant sent out from each outlet 511 through each outlet pipe 52. When the liquid-phase refrigerant distribution ratio of the reference outlet pipe 52a, from which the amount of the liquid-phase refrigerant sent out is the largest when no measures are taken for any of the eight outlet pipes 52, becomes smaller, the liquid-phase refrigerant distribution ratio 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 bias of the liquid-phase refrigerant from the reference outlet pipe 52a becomes larger, and the variation in the amount of the refrigerant sent out from each outlet 511 becomes smaller.

[0041] In FIG. 7, the broken line showing the relationship between the height h of the mixing section 51 and the liquid-phase refrigerant distribution ratio of the reference outlet pipe 52a has a downwardly convex shape regardless of the value of the mass flow rate G of the refrigerant. As is clear from this, the liquid-phase refrigerant distribution ratio of the reference outlet pipe 52a becomes the minimum value when the height h of the mixing section 51 is a specific value, and is larger than the minimum value in both cases where the height h is smaller and larger than the specific value. Therefore, by setting the height h of the mixing section 51 to an appropriate value, the liquid-phase refrigerant distribution ratio of the reference outlet pipe 52a can be reduced, and the variation in the amount of refrigerant delivered from each outlet 511 can be reduced.

[0042] FIG. 8 shows an example of the flow of the refrigerant inside the refrigerant distributor 31 when the refrigerant in the 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. FIG. 8 shows a longitudinal section of the refrigerant distributor 31 cut by a cutting plane that includes the axis of the inlet pipe 50 and is perpendicular to the Y-axis direction. In FIG. 8, the arrow AA indicates the flow of the liquid-phase refrigerant CC contained in the refrigerant, and the arrow BB indicates the flow of the gas-phase refrigerant contained in the refrigerant. The gas-phase refrigerant flows through the central portion of the inlet pipe 50 as shown by the arrow BB, flows into the recessed portion 53 after being sent out from the inlet 510, collides with the inner wall of the recessed portion 53, and diffuses in the circumferential direction of the opening 51c of the mixing section 51. Thereafter, the gas-phase refrigerant flows along the inner wall of the recessed portion 53 and flows into the mixing section 51. The gas-phase refrigerant that has flowed into the mixing section 51 flows along the inner wall of the inlet pipe 50 in a liquid film state and collides with the liquid-phase refrigerant CC that has flowed into the mixing section 51 from the inlet 510 inside the mixing section 51. After colliding with the liquid-phase refrigerant CC, the gas-phase refrigerant flows along the downstream end portion 51b of the mixing section 51 toward the side wall 51d of the mixing section 51.

[0043] Figs. 9(A) to 9(C) show longitudinal cross-sections of the refrigerant distributor 31 cut along a cutting 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 refrigerant flow inside the refrigerant distributor 31 when the liquid-phase refrigerant distribution ratio of the reference outlet pipe 52a is suppressed. In the example of Fig. 9(A), inside the mixing section 51, the vapor-phase refrigerant collides with the liquid-phase refrigerant CC, causing the liquid-phase refrigerant CC to be 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, then flows along the side wall 51d, reaches the downstream end 51b of the mixing section 51, and is sent from the outlet 511 to the reference outlet pipe 52a. While flowing along the upstream end 51a and the side wall 51d of the mixing section 51, the liquid-phase refrigerant CC diffuses in the circumferential direction of the downstream end 51b of the mixing section 51. As a result, a part of the liquid-phase refrigerant CC that flowed into the mixing section 51 in a state 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 sent from each outlet 511 becomes smaller.

[0044] Fig. 9(B) shows an example of the refrigerant flow inside the refrigerant distributor 31 when the liquid-phase refrigerant distribution ratio 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 internal space of the mixing section 51 is higher than that in the example of Fig. 9(A). For this reason, in the example of Fig. 9(B), the flow rate of the vapor-phase refrigerant flowing toward the side wall 51d of the mixing section 51 after colliding with the liquid-phase refrigerant CC inside the mixing section 51 is smaller than that in the example of Fig. 9(A). The vapor-phase refrigerant flowing 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 part of the liquid-phase refrigerant CC flowing in from the inlet 510 is dragged by the vapor-phase refrigerant that has bent in the direction of flowing into the reference outlet pipe 52a and directly flows into the reference outlet pipe 52a without flowing along the upstream end 51a and the side wall 51d of the mixing section 51.

[0045] FIG. 9(C) shows an example of the refrigerant flow 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 large. In the example of FIG. 9(C), after flowing in from the inlet 510, the amount of vapor-phase refrigerant flowing 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). For this reason, the force applied to the liquid-phase refrigerant CC from the vapor-phase refrigerant and pressing 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, as shown in FIG. 9(C), after flowing into the mixing section 51 from the inlet 510, the liquid-phase refrigerant CC does not flow along the upstream end 51a and the side wall 51d of the mixing section 51, but directly flows into the reference outlet pipe 52a.

[0046] In the examples of FIGS. 9(B) and 9(C), since the liquid-phase refrigerant CC flowing in from the inlet 510 directly flows into the reference outlet pipe 52a, the liquid-phase refrigerant CC does not diffuse in the circumferential direction of the downstream end 51b of the mixing section 51 before being sent from the outlet 511 to the reference outlet pipe 52a. The liquid-phase refrigerant distribution rate of the reference outlet pipe 52a is not suppressed, and the variation in the amount of the liquid-phase refrigerant CC sent from each outlet 511 is not suppressed either. On the contrary, in the example of FIG. 9(A), the direct flow of the liquid-phase refrigerant CC into the reference outlet pipe 52a is suppressed, the liquid-phase refrigerant distribution rate of the reference outlet pipe 52a is suppressed, and the variation in the amount of the liquid-phase refrigerant CC sent from each outlet 511 is suppressed.

[0047] When the height h of the mixing section 51 is such that the liquid-phase refrigerant CC flows directly into the reference outlet pipe 52a, not only when centrifugal force is applied to the refrigerant in the curved section 40 of the internal refrigerant pipe 32, but also when gravity acts on the refrigerant in a direction not parallel to the direction of the refrigerant flow, variations occur in the amount of the liquid-phase refrigerant CC delivered from each outlet 511. Specifically, when the axis of the inlet pipe 50 is inclined with respect to the gravitational direction g, gravity is applied to the refrigerant flowing inside the inlet pipe 50 in a direction not parallel to the direction of the refrigerant flow, and the liquid-phase refrigerant CC contained in the refrigerant becomes biased. When the refrigerant flows into the mixing section 51 from the inlet 510 in a state where the liquid-phase refrigerant CC is biased by the action of gravity, if the liquid-phase refrigerant CC flows directly into the reference outlet pipe 52a, variations occur in the amount of the liquid-phase refrigerant CC delivered from each outlet 511. By suppressing the direct flow of the liquid-phase refrigerant CC into the reference outlet pipe 52a, the variations in the amount of the liquid-phase refrigerant CC delivered from each outlet 511 due to the inclination of the axis of the inlet pipe 50 with respect to the gravitational direction g are reduced.

[0048] When arranging the refrigerant distributor 31 inside the indoor heat exchanger 3 or the outdoor heat exchanger 4, if the refrigerant distributor 31 is installed such that the axis of the inlet pipe 50 is parallel to the gravitational direction g, the bias of the liquid-phase refrigerant CC caused by the action of gravity described above does not occur. However, in practice, it is difficult to install the refrigerant distributor 31 such that the axis of the inlet pipe 50 is completely parallel to the gravitational direction g, and the refrigerant distributor 31 is usually installed in a state where the axis of the inlet pipe 50 is slightly inclined with respect to the gravitational direction g.

[0049] Returning to FIG. 8, when the diameter Dc of the recess in the mixing portion 51, which is the internal space of the recess portion 53, is smaller than the inner diameter Di of the inlet 510, the area where the gaseous-phase refrigerant flowing into the mixing portion 51 from the recess portion 53 contacts the liquid-phase refrigerant CC flowing into the mixing portion 51 from the inlet 510 is small. As a result, the force with which the gaseous-phase refrigerant presses the liquid-phase refrigerant CC against the upstream end portion 51a of the mixing portion 51 is small, and the liquid-phase refrigerant CC easily flows directly into the reference outlet pipe 52a. In the present embodiment, the diameter Dc of the recess in the mixing portion 51 is configured to be larger than the inner diameter Di of the inlet 510. According to such a configuration, the area where the gaseous-phase refrigerant flowing into the mixing portion 51 from the recess portion 53 contacts the liquid-phase refrigerant CC flowing into the mixing portion 51 from the inlet 510 is large, and the force with which the gaseous-phase refrigerant presses the liquid-phase refrigerant CC against the upstream end portion 51a of the mixing portion 51 is large. As a result, the direct flow of the liquid-phase refrigerant CC into the reference outlet pipe 52a is suppressed, the liquid-phase refrigerant distribution rate of the reference outlet pipe 52a is suppressed, and the variation in the amount of the liquid-phase refrigerant CC sent out from each outlet 511 is reduced.

[0050] FIG. 10 shows the relationship between the mass flow rate G of the refrigerant in the gas-liquid two-phase state flowing from the internal refrigerant pipe 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 portion 51 is 2 [mm], 3 [mm], 4 [mm], or 5 [mm], which is obtained by simulation. As shown in FIG. 10, regardless of the height h of the mixing portion 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 gaseous-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 gaseous-phase refrigerant and the dynamic pressure of the liquid-phase refrigerant CC. The larger the difference between the dynamic pressure of the gaseous-phase refrigerant and the dynamic pressure of the liquid-phase refrigerant CC, the larger the force with which the gaseous-phase refrigerant presses the liquid-phase refrigerant CC against the upstream end portion 51a of the mixing portion 51 when the gaseous-phase refrigerant flowing into the mixing portion 51 from the recess portion 53 collides with the liquid-phase refrigerant CC flowing into the mixing portion 51 from the inlet 510. The larger the force with which the gaseous-phase refrigerant presses the liquid-phase refrigerant CC against the upstream end portion 51a of the mixing portion 51, the more the direct flow of the liquid-phase refrigerant CC into the reference outlet pipe 52a is suppressed, and the smaller the liquid-phase refrigerant distribution rate of the reference outlet pipe 52a becomes.

[0051] 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 gas phase density ρ g Liquid density ρ l The density ratio ρ l / ρ g is the density ratio of R290, ρ l / ρ g As shown in Figure 11, the density ratio ρ l / ρ g The density ratio of the refrigerant is ρ l / ρ g The height h of the mixing section 51 at which the liquid phase refrigerant distribution ratio of the reference outlet pipe 52a becomes the minimum is larger and the minimum value is smaller than that in the case of R290, which has a smaller density ratio of the refrigerant. l / ρ g The larger the difference between the velocity of the gas phase refrigerant and the velocity 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 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.

[0052] 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.

[0053] As described above, the liquid-phase refrigerant distribution rate of the reference outlet pipe 52a is determined by the height h of the mixing section 51, the mass flow rate G of the refrigerant, and the density ratio ρ l / ρ g and depends on the mass flux of the refrigerant. Based on this, the following formula 2, which expresses the liquid-phase refrigerant distribution rate X of the reference outlet pipe 52a, was obtained by approximating the results of the simulation.

[0054]

Number

[0055] According to the simulation results, regardless of the height h of the mixing section 51, the mass flow rate G of the refrigerant, the type of the 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 part of the liquid-phase refrigerant CC sent from the inlet pipe 50 directly flows into the reference outlet pipe 52a. When the liquid-phase refrigerant distribution ratio X of the reference outlet pipe 52a is less than 0.13, the liquid-phase refrigerant CC did not directly flow 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 represented by the above formula 2 is less than 0.13 is represented by the above formula 1.

[0056] As described above, in the present embodiment, the height h of the mixing section 51 satisfies Formula 1. In other words, the height h of the mixing section 51 is a value within the range represented by Formula 1. Thereby, the liquid-phase refrigerant distribution ratio X of the reference outlet pipe 52a represented by the above formula 2 becomes less than 0.13, and regardless of the mass flow rate G of the refrigerant, the type of the refrigerant, and the temperature of the refrigerant, the liquid-phase refrigerant CC contained in the refrigerant is suppressed from directly flowing into the reference outlet pipe 52a. In other words, since the height h of the mixing section 51 satisfies 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 the refrigerant, and the temperature of the refrigerant, and after diffusing in the circumferential direction of the downstream end 51b of the mixing section 51, it is sent out from the outlet 511. According to such a configuration, regardless of the mass flow rate G of the refrigerant, the type of the refrigerant, and the temperature of the refrigerant, the variation in the amount of the liquid-phase refrigerant CC sent out from each outlet 511 becomes small. Further, since the direct flow of the liquid-phase refrigerant CC into the reference outlet pipe 52a is suppressed, the variation in the amount of the liquid-phase refrigerant CC sent out from each outlet 511 due to the inclination of the axis of the inlet pipe 50 with respect to the gravitational direction g becomes small.

[0057] Using a computer, when parameters such as the number of outlet pipes 52, the inner diameter Di of the inlet 510, the diameter Dc of the depression of the mixing section 51, the first distance Li, and the second distance Lo are set to various values, a simulation of the refrigerant flow inside the refrigerant distributor 31 is performed when the height h of the mixing section 51 satisfies Equation 1. As a result, regardless of the values of these parameters, the direct inflow of the liquid-phase refrigerant CC into the reference outlet pipe 52a was suppressed. That is, when the height h of the mixing section 51 satisfies Equation 1, regardless of the number of outlet pipes 52, the inner diameter Di of the inlet 510, the diameter Dc of the depression of the mixing section 51, the first distance Li, and the second distance Lo, the direct inflow of the liquid-phase refrigerant CC into the reference outlet pipe 52a is suppressed. Furthermore, when the height h of the mixing section 51 is set to various values within the range that satisfies Equation 1 and a similar simulation is performed, when the height h of the mixing section 51 is 2.5 [mm] or more and 4 [mm] or less, regardless of the values of the above-mentioned parameters, the direct inflow of the liquid-phase refrigerant CC into the reference outlet pipe 52a was significantly suppressed. As described above, in the present embodiment, the height h of the mixing section 51 is 2.5 [mm] or more and 4 [mm] or less. According to such a configuration, 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 510, the diameter Dc of the depression 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 sent out from each outlet 511 is reduced.

[0058] As described above, in the present embodiment, the height h of the mixing section 51 satisfies the above formula (1). Thereby, 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, diffuses in the circumferential direction of the downstream end 51b, and then is sent out from the outlet 511. According to such a configuration, regardless of the flow rate, type, and temperature of the refrigerant in the gas-liquid two-phase state flowing in from the inlet 510, the variation in the amount of refrigerant sent out from each outlet 511 becomes small. As a result, the variation in the amount of refrigerant distributed to the heat transfer tubes 30 from each outlet 511 through each outlet pipe 52 connected to each outlet 511 becomes small regardless of the flow rate, type, and temperature of the refrigerant. That is, according to such a configuration, when distributing the refrigerant to the 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.

[0059] 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 heat load of the refrigerant in each heat transfer tube 30 and reducing the variation in the section where the refrigerant flows in the gas-phase single-phase state in each heat transfer tube 30. Thereby, the heat exchange efficiency of the indoor heat exchanger 3 and the outdoor heat exchanger 4 provided with the refrigerant distributor 31 and functioning as an evaporator is improved, and the air conditioning efficiency of the air conditioner 100 provided with the indoor heat exchanger 3 and the outdoor heat exchanger 4 is improved.

[0060] Further, in the present embodiment, the diameter Dc of the recess of the mixing section 51 is larger than the inner diameter Di of the inlet 510. According to such a configuration, the variation in the amount of refrigerant sent out from each outlet 511 can be reduced.

[0061] Further, in the present embodiment, the outlet 511 is disposed away from the recess formed in the mixing portion 51 and radially outward of the downstream end portion 51b of the mixing portion 51. A first distance Li, which is the distance between the recess of the mixing portion 51 and the axis QQ of the outlet 511, is greater than a second distance Lo, which is the distance between the axis QQ of the outlet 511 and the side wall 51d of the mixing portion 51. According to such a configuration, the processing in manufacturing the refrigerant distributor 31 can be facilitated, and the manufacturing cost can be suppressed.

[0062] In the present embodiment, although the diameter Dc of the recess of the mixing portion 51 has been described as being larger than the inner diameter Di of the inlet 510, this is merely an example. The diameter Dc of the recess of the mixing portion 51 may be equal to or less than the inner diameter Di of the inlet 510.

[0063] In the present embodiment, although the first distance Li has been described as being greater than the second distance Lo, this is merely an example. The first distance Li may be equal to or less than the second distance Lo.

[0064] In the present embodiment, although the height h of the mixing portion 51 has been described as being 2.5 [mm] or more and 4 [mm] or less, this is merely an example, and the height h of the mixing portion 51 may be any value that satisfies Equation 1.

[0065] (Embodiment 2) Hereinafter, Embodiment 2 of the present disclosure for reducing the pressure loss of the refrigerant inside the refrigerant distributor 31 will be described focusing on the differences from Embodiment 1.

[0066] 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 vapor-phase refrigerant flowing from the evaporator into the compressor 1 decreases. As a result, the energy that must be applied to the vapor-phase refrigerant to change the low-pressure vapor-phase refrigerant flowing into the compressor 1 into a high-pressure vapor-phase refrigerant increases, and in order to supply this energy, it becomes necessary to increase the frequency of the compressor 1. When the frequency of the compressor 1 is increased, the energy-saving performance of the air conditioner 100 deteriorates.

[0067] Vapor density ρ of the refrigerant g The smaller the vapor density ρ of the refrigerant is, the higher the flow velocity of the refrigerant in the vapor phase state is, and the greater the pressure loss of the refrigerant inside the refrigerant distributor 31 is. The vapor density ρ of the refrigerant g is 20 [kg / m 3 or less, the decrease in the energy-saving performance of the air conditioner 100 due to the pressure loss of the refrigerant inside the refrigerant distributor 31 is so large that it cannot be ignored. In the present embodiment, the vapor density ρ of the refrigerant g is 20 [kg / m 3 or less.

[0068] In the present embodiment, the height h of the mixing section 51 satisfies the above formula (1), is greater than 10 / 3 [mm], and is 4 [mm] or less. As will be described later, according to such a configuration, the pressure loss of the refrigerant inside the refrigerant distributor 31 can be reduced, and the energy-saving performance of the air conditioner 100 can be improved.

[0069] Hereinafter, regarding the reduction of the pressure loss of the refrigerant inside the refrigerant distributor 31, the result of the simulation of the flow of the refrigerant inside the refrigerant distributor 31 when the refrigerant in the gas-phase single-phase state flows into the inlet pipe 50, which was performed using a computer, will be used for explanation. This simulation was performed under the conditions that the diameter Dc of the recess of the mixing section 51 = 7 [mm], the inner diameter Di of the inlet 510 = 6 [mm], the first distance Li = 8.5 [mm], and the 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].

[0070] 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 the gas-phase single-phase state flowing into the inlet pipe 50 is 50 [kg / h], 100 [kg / h], 150 [kg / h], or 200 [kg / h], which is obtained 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 sent out 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.

[0071] 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 ρ of the refrigerant. g For this reason, the pressure loss ΔP of the refrigerant can be expressed by the following Equation 3. In Equation 3, f(h) is a function with the height h of the mixing section 51 as a variable.

[0072]

Equation

[0073] By approximating the results of the simulation, the following Equation 4 representing the above function f(h) was obtained.

[0074]

Equation

[0075] 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. That is, the larger the height h of the mixing section 51, the easier it is for the refrigerant to flow inside the refrigerant distributor 31. For this reason, 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. Further, hereinafter, the ratio of the pressure loss ΔP of the refrigerant to the reference pressure loss is referred to as the pressure loss ratio.

[0076] As the height h of the mixing section 51 increases, the increase amount of the value of the function f(h) when the height h of the mixing section 51 increases by a unit amount decreases. For this reason, as the height h of the mixing section 51 increases, the decrease amount of the pressure loss ΔP of the refrigerant when the height h of the mixing section 51 increases by a unit amount decreases.

[0077] When the pressure loss ratio is within 130%, the decrease amount of the pressure loss ΔP of the refrigerant when the height h of the mixing section 51 increases by a unit amount is extremely small. For this reason, in a state where the pressure loss ratio is within 130%, it is extremely difficult to reduce the pressure loss ΔP of the refrigerant by increasing the height h of the mixing section 51. Therefore, the pressure loss ΔP of the refrigerant substantially reaches the minimum value when the pressure loss ratio is within 130%.

[0078] According to the simulation results, 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 the present embodiment, the height h of the mixing section 51 is greater than 10 / 3 [mm]. According to such a configuration, the pressure loss ΔP of the refrigerant can be suppressed to a substantially minimum value. Thereby, the energy-saving performance of the air conditioner 100 is improved. When the simulation conditions such as the mass flow rate G of the refrigerant, the type of the 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 are set to various conditions using a computer, a simulation of the flow of the refrigerant inside the refrigerant distributor 31 was performed when the height h of the mixing section 51 was greater than 10 / 3 [mm]. As a result, regardless of these simulation conditions, the pressure loss ratio was within 130%. That is, when the height h of the mixing section 51 is greater than 10 / 3 [mm], the pressure loss ratio is suppressed within 130% regardless of the mass flow rate G of the refrigerant, the type of the 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.

[0079] As described above, in the present embodiment, the height h of the mixing section 51 is greater than 10 / 3 [mm]. According to such a configuration, the pressure loss ΔP of the refrigerant inside the refrigerant distributor 31 can be reduced, and the energy-saving performance of the air conditioner 100 can be improved.

[0080] In addition, in the present embodiment, the height h of the mixing section 51 has been 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 Equation 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 larger than the straight line DD is the region where the height h of the mixing section 51 is larger 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 Equation 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 Equation 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 Equation 1 and is larger than 10 / 3 [mm].

[0081] (Embodiment 3) Hereinafter, Embodiment 3 of the present disclosure in which the refrigerant distributor 31 includes a guiding portion that guides the vapor-phase refrigerant to the upstream end portion 51a of the mixing section 51 will be described focusing on the differences from Embodiment 1.

[0082] The refrigerant distributor 31 according to the present embodiment is different from the refrigerant distributor 31 according to the first embodiment in that, as shown in FIG. 14(A), it includes a guiding portion 54 connected to the downstream end portion 51b of the mixing portion 51. In FIG. 14(A), for ease of understanding, the guiding portion 54 is hatched. The guiding portion 54 has an annular shape with the same axis as the axes of the mixing portion 51 and the recessed portion 53 in a front view. The guiding portion 54 is disposed away from the inside space of the recessed portion 53, which is the mixing portion 51, to the radially outer side of the downstream end portion 51b of the mixing portion 51. That is, the guiding portion 54 is disposed away from the recess formed in the mixing portion 51, which is the space inside the recessed portion 53, to the radially outer side of the downstream end portion 51b of the mixing portion 51. Further, the guiding portion 54 is disposed away from the outlet 511 and the outlet pipe 52 to the radially inner side of the downstream end portion 51b of the mixing portion 51.

[0083] As shown in FIG. 14(B), the guiding portion 54 is provided so as to project in a direction approaching the upstream end portion 51a of the mixing portion 51. FIG. 14(B) is a cross-sectional view of the refrigerant distributor 31 according to the present embodiment cut along the line A-A shown in FIG. 14(A). The guiding portion 54 includes a first side wall 54a inclined with respect to the downstream end portion 51b of the mixing portion 51 and a second side wall 54b perpendicular to the downstream end portion 51b of the mixing portion 51. The first side wall 54a is an example of a guiding side wall. The second side wall 54b is disposed on the radially outer side of the downstream end portion 51b of the mixing portion 51 more than the first side wall 54a.

[0084] 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 radially outward from the inner end 60 and away from 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 arranged closer to the upstream end 51a of the mixing section 51 than the inner end 60 of the first side wall 54a.

[0085] FIG. 15 shows an example of the flow of the refrigerant inside the refrigerant distributor 31 when the refrigerant in the 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 being biased in the +X-axis direction. FIG. 15 shows a longitudinal section of the refrigerant distributor 31 cut by a cutting plane that includes the axis of the inlet pipe 50 and is perpendicular to the Y-axis direction. In FIG. 15, arrow AA indicates the flow of the liquid-phase refrigerant CC, and arrow BB indicates the flow of the gas-phase refrigerant. After flowing into the recessed portion 53 and then into the mixing section 51, the gas-phase refrigerant that has flowed into the mixing section 51 from the recessed portion 53 collides with the liquid-phase refrigerant CC that has flowed 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 and toward the side wall 51d of the mixing section 51 as indicated by 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 and toward the side wall 51d of the mixing section 51 as indicated by arrow BB and reaches the guiding section 54.

[0086] The vapor-phase refrigerant that has reached the guiding portion 54 flows along the first side wall 54a of the guiding portion 54 from the downstream end portion 51b to the upstream end portion 51a of the mixing portion 51. That is, the vapor-phase refrigerant is guided by the first side wall 54a of the guiding portion 54 from the downstream end portion 51b to the upstream end portion 51a of the mixing portion 51. Thereby, the inflow of the vapor-phase refrigerant into the reference outlet pipe 52a is suppressed, and the liquid-phase refrigerant CC is prevented from being dragged by the vapor-phase refrigerant flowing into the outlet 511 and directly flowing into the reference outlet pipe 52a. By suppressing the direct inflow 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 the liquid-phase refrigerant CC sent out from each outlet 511 is reduced.

[0087] According to such a configuration, even when the height h of the mixing portion 51 is smaller than the size required to suppress the liquid-phase refrigerant distribution rate X of the reference outlet pipe 52a as in the example of FIG. 9(B) described above, the inflow of the vapor-phase refrigerant into the reference outlet pipe 52a is suppressed by the guiding portion 54. Thereby, the direct inflow of the liquid-phase refrigerant CC into the reference outlet pipe 52a is suppressed, and the liquid-phase refrigerant distribution rate X of the reference outlet pipe 52a is suppressed.

[0088] As described above, the first side wall 54a of the guiding portion 54 forms an angle θ of 45° or more and less than 90° with respect to the downstream end portion 51b of the mixing portion 51. According to such a configuration, the vapor-phase refrigerant is more easily guided by the first side wall 54a to the upstream end portion 51a of the mixing portion 51, and the outflow of the vapor-phase refrigerant into the reference outlet pipe 52a can be more effectively suppressed. Thereby, the direct inflow of the liquid-phase refrigerant CC into the reference outlet pipe 52a is more effectively suppressed, the liquid-phase refrigerant distribution rate X of the reference outlet pipe 52a is more effectively suppressed, and the variation in the amount of the liquid-phase refrigerant CC sent out from each outlet 511 can be more effectively suppressed.

[0089] As described above, in the present embodiment, the refrigerant distributor 31 guides the vapor-phase refrigerant flowing into the mixing section 51 from the downstream end portion 51b to the upstream end portion 51a of the mixing section 51 by the guiding section 54 connected to the downstream end portion 51b of the mixing section 51. According to such a configuration, it is possible to suppress the liquid-phase refrigerant CC from directly flowing into the reference outlet pipe 52a, suppress the liquid-phase refrigerant distribution ratio X of the reference outlet pipe 52a, and reduce the variation in the amount of the liquid-phase refrigerant CC sent out from each outlet 511.

[0090] In addition, in the present embodiment, although the guiding section 54 has been described as being provided to protrude in a direction approaching the upstream end portion 51a of the mixing section 51, this is merely an example. As shown in FIG. 16, the guiding section 54 may be provided to protrude in a direction away from the upstream end portion 51a of the mixing section 51. FIG. 16 is a longitudinal sectional view of the refrigerant distributor 31 cut by a cutting plane that includes the axis of the inlet pipe 50 and is perpendicular to the Y-axis direction, of the refrigerant distributor 31 according to this modification. In the modification shown in FIG. 16, the second side wall 54b of the guiding section 54 is arranged radially inside the downstream end portion 51b of the mixing section 51 than the first side wall 54a. In this modification, similar to the third embodiment described above, the first side wall 54a forms an angle θ that is 45° or more and less than 90° with respect to the downstream end portion 51b of the mixing section 51. The inner end portion 60 of the first side wall 54a is connected to the second side wall 54b. The outer end portion 61 of the first side wall 54a is connected to the downstream end portion 51b of the mixing section 51. In this modification, similar to the third embodiment described above, the third distance Lp, which is the distance between the outer end portion 61 of the first side wall 54a and the upstream end portion 51a of the mixing section 51, is smaller than the fourth distance Lq, which is the distance between the inner end portion 60 of the first side wall 54a and the upstream end portion 51a of the mixing section 51. That is, the outer end portion 61 of the first side wall 54a is arranged closer to the upstream end portion 51a of the mixing section 51 than the inner end portion 60 of the first side wall 54a.

[0091] In addition, in the present embodiment, although the second side wall 54b of the guiding section 54 has been described as being perpendicular to the downstream end portion 51b of the mixing section 51, this is merely an example. The second side wall 54b of the guiding section 54 may be configured to form an angle less than 90° with respect to the downstream end portion 51b of the mixing section 51.

[0092] (Modification example) 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.

[0093] For example, in the above Embodiments 1 to 3, the air conditioner 100 has been described as a specific example of the refrigeration cycle device, but this is merely an 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, and a freezer.

[0094] In the above Embodiments 1 to 3, the indoor heat exchanger 3 and the outdoor heat exchanger 4, which are examples of the heat exchanger, have been described as exchanging heat between the refrigerant and air, but this is merely an example. The heat exchanger according to the present disclosure can exchange heat between the refrigerant and any substance. For example, when the heat exchanger according to the present disclosure is provided in a heat pump water heater, the heat exchanger exchanges heat between the refrigerant and water.

[0095] In the above Embodiments 1 to 3, the refrigerant distributor 31 has been described as being arranged at the inlets of the indoor heat exchanger 3 and the outdoor heat exchanger 4, but this is merely an example. The refrigerant distributor according to the present disclosure may be arranged in the middle of the heat exchanger. Specifically, a throttling device is arranged in the middle of the refrigerant path of the indoor heat exchanger. During the cooling operation, a plurality of refrigerant paths located upstream of the throttling device function as condensers, and a plurality of refrigerant paths located downstream of the throttling device function as evaporators. A reheating and dehumidifying type air conditioner is known. In such a reheating and dehumidifying type air conditioner, the refrigerant distributor according to the present disclosure may be arranged in the middle of the refrigerant path of the indoor heat exchanger to distribute the refrigerant to a plurality of refrigerant paths downstream of the throttling device.

[0096] In the above Embodiments 1 to 3, the number of the heat transfer tubes 30 and the outlet tubes 52 has been described as being eight, but this is merely an example. The number of the heat transfer tubes 30 and the outlet tubes 52 may be any number of two or more.

[0097] In the above-described Embodiments 1 to 3, the recessed portion 53 has been described as having a shape in which a cone is connected to a cylinder, but this is merely an example. The shape of the recessed portion 53 may be any shape. For example, the shape of the recessed portion 53 may be a hemispherical shape.

[0098] In the above-described Embodiments 1 to 3, the inner diameter of the inlet pipe 50 has been described as being equal to the inner diameter of the straight pipe portion 41 of the internal refrigerant pipe 32, but this is merely an example. The inner diameter of the inlet pipe 50 may be different from the inner diameter of the straight pipe portion 41. In this case, the method of connecting the inlet pipe 50 and the straight pipe portion 41 is arbitrary. For example, the inlet pipe 50 and the straight pipe portion 41 may be connected via a pipe having a tapered shape with a decreasing inner diameter. Alternatively, the inlet pipe 50 and the straight pipe portion 41 may be connected via a stepped rod-shaped pipe.

[0099] In the above-described Embodiments 1 to 3, the internal refrigerant pipe 32 has been described as being connected to the inlet 510 via the inlet pipe 50, but this is merely an example, and the internal refrigerant pipe 32 may be directly connected to the inlet 510. In this case, the end portion of the internal refrigerant pipe 32 functions as the inlet pipe 50.

[0100] In the above-described Embodiments 1 to 3, each heat transfer pipe 30 has been described as being connected to each outlet 511 via each outlet pipe 52, but this is merely an example, and each heat transfer pipe 30 may be directly connected to the outlet 511. In this case, the end portion of each heat transfer pipe 30 functions as the outlet pipe 52.

[0101] Embodiments 1 to 3 can be combined with each other. As an example, a guiding portion 54 according to Embodiment 3 may be provided in the refrigerant distributor 31 according to Embodiment 2. According to such a configuration, the variation in the amount of refrigerant delivered from each outlet pipe 52 can be reduced, the pressure loss of the refrigerant inside the refrigerant distributor 31 can be reduced, and the energy-saving performance of the air conditioner 100 can be improved.

[0102] The present disclosure can have various embodiments and modifications without departing from the broad spirit and scope of the present disclosure. Further, the above-described embodiments are for explaining the present disclosure and do not limit the scope of the present disclosure. That is, the scope of the present disclosure is indicated by the claims rather than the embodiments. And various modifications made within the scope of the claims and within the scope of the meaning of the disclosure equivalent thereto are considered to be within the scope of the present disclosure.

[0103] 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.

Explanation of Signs

[0104] 1 Compressor, 2 Throttling device, 3 Indoor heat exchanger, 4 Outdoor heat exchanger, 5 Main refrigerant pipe, 6 Indoor unit, 7 Outdoor unit, 10 Refrigerant circuit, 20 Control device, 30 Heat transfer pipe, 31 Refrigerant distributor, 32 Internal refrigerant pipe, 39 Connection part, 39a Axis of the connection part, 40 Bending part, 41 Straight pipe part, 41a Axis of the straight pipe part, 50 Inlet pipe, 51 Mixing part, 51a Upstream end, 51b Downstream end, 51c Opening, 51d Side wall, 52 Outlet pipe, 52a Reference outlet pipe, 53 Depression part, 54 Induction part, 54a First side wall, 54b Second side wall, 60 Inner end, 61 Outer end, 100 Air conditioner, 510 Inlet, 511 Outlet, AA Flow of liquid-phase refrigerant, BB Flow of vapor-phase refrigerant, CC Liquid-phase refrigerant, DD Straight line, EE Curve, FF Region, Dc Diameter of the depression of the mixing part, Di Inner diameter of the inlet, h Height of the mixing part, Li First distance, Lo Second distance, Lp Third distance, Lq Fourth distance, MM Saturated liquid line, NN Saturated vapor line, QQ Axis of the outlet, TL Straight line passing through the axis of the connection part and the axis of the straight pipe part.

Claims

1. comprising a mixing section having a cylindrical shape, a refrigerant inlet through which refrigerant flows is formed at a first end of the mixing section, a plurality of refrigerant outlets through which refrigerant flows out are formed at a second end of the mixing section opposite to the first end, a recess facing the inlet is formed at the second end of the mixing section, the mixing section guides the vapor-phase refrigerant contained in the refrigerant flowing from the inlet to the recess so as to collide with the liquid-phase refrigerant contained in the refrigerant flowing from the inlet, thereby pressing the liquid-phase refrigerant against the first end of the mixing section and guiding it to flow along the first end of the mixing section and the side wall of the mixing section and diffuse in the circumferential direction of the second end, and then sending it out from the outlet, further comprising a guiding section disposed at the second end of the mixing section, the guiding section guides the vapor-phase refrigerant induced into the mixing section and collided with the liquid-phase refrigerant from the second end of the mixing section to the first end of the mixing section, a refrigerant distributor.

2. the guiding section is disposed away from the second end of the mixing section in the radial direction outside, and is disposed away from the second end of the mixing section in the radial direction inside from the outlet, the guiding section includes a guiding side wall inclined with respect to the main surface of the second end of the mixing section, the guiding side wall has an inner end and an outer end separated from the inner end in the radial direction outside of the second end of the mixing section, the outer end of the guiding side wall is disposed closer to the first end of the mixing section than the inner end of the guiding side wall, the refrigerant distributor according to claim 1.

3. 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 vapor density of the refrigerant is ρg [kg / m3], and the liquid density of the refrigerant is ρl [kg / m3], the height h [mm] of the mixing section, which is the distance between the first end and the second end in the internal space of the mixing section, satisfies Equation 1, the refrigerant distributor according to claim 1 or 2. 【Number 1】

4. comprising a mixing section having a cylindrical shape, a refrigerant inlet through which refrigerant flows is formed at a first end of the mixing section, a plurality of refrigerant outlets through which refrigerant flows out are formed at a second end of the mixing section opposite to the first end, a recess facing the inlet is formed at the second end of the mixing section, The mixing part guides the refrigerant flowing in from the inlet to flow along the first end part of the mixing part and the side wall of the mixing part, diffuses in the circumferential direction of the second end part, and then is sent 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 ρg [kg / m3], and the liquid-phase density of the refrigerant is ρl [kg / m3], the height h [mm] of the mixing part, which is the distance between the first end part and the second end part in the internal space of the mixing part, satisfies Formula 2. Refrigerant distributor. 【No. 2】

5. The mixing part guides the gas-phase refrigerant contained in the refrigerant flowing into the recess to collide with the liquid-phase refrigerant contained in the refrigerant flowing in from the inlet, thereby pressing the liquid-phase refrigerant against the first end part of the mixing part, guiding it to flow along the first end part of the mixing part and the side wall of the mixing part, diffusing in the circumferential direction of the second end part, and then sending it out from the outlet. The refrigerant distributor according to claim 4.

6. The mixing part further includes a guiding part arranged at the second end part of the mixing part. The guiding part is arranged to be separated from the second end part of the mixing part in the radial direction outside the recess, and is arranged to be separated from the second end part of the mixing part in the radial direction inside the outlet. The guiding part includes a guiding side wall inclined with respect to the main surface of the second end part of the mixing part. The guiding side wall has an inner end part and an outer end part separated from the inner end part in the radial direction outside the second end part of the mixing part. The outer end part of the guiding side wall is arranged closer to the first end part of the mixing part than the inner end part of the guiding side wall. The refrigerant distributor according to claim 4 or 5.

7. The outlet is arranged to be separated from the second end part of the mixing part in the radial direction outside the recess. A first distance, which is the distance between the axis of the recess and the axis of the outlet, is larger than a second distance, which is the distance between the axis of the outlet and the side wall of the mixing part. The refrigerant distributor according to claim 1 or 4.

8. The height h of the mixing part is 2.5 [mm] or more and 4 [mm] or less. The refrigerant distributor according to claim 1 or 4.

9. An inlet pipe connected to the inlet. An outlet pipe connected to the outlet. The refrigerant distributor further includes the following. The refrigerant distributor according to claim 1 or 4.

10. The height h of the mixing section is greater than 10 / 3 [mm], The refrigerant distributor according to claim 1 or 4.

11. The refrigerant distributor according to claim 1 or 4, A plurality of heat transfer tubes connected to the outlet, Comprising, Heat exchanger.

12. Comprising a refrigerant circuit for circulating refrigerant, The refrigerant circuit includes the heat exchanger according to claim 11, a compressor for compressing the refrigerant, and a throttling device for expanding the refrigerant, Comprising, Refrigeration cycle device.

13. The refrigerant distributor according to claim 1 or 4, An internal refrigerant pipe connected to the inlet, Comprising, The internal refrigerant pipe has a linear shape and includes a straight pipe portion connected to the inlet, and a curved portion located upstream of the straight pipe portion and having a U shape and connected to the straight pipe portion. Heat exchanger.

14. Comprising a refrigerant circuit for circulating refrigerant, The refrigerant circuit includes the heat exchanger according to claim 13, a compressor for compressing the refrigerant, and a throttling device for expanding the refrigerant, Comprising, Refrigeration cycle device.

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