Refrigerant distributor, heat exchanger and air conditioning unit

Abstract

The refrigerant distributor disclosed herein comprises: an outer tube in which refrigerant flows, and a plurality of heat-conducting tubes connected to the outer tube at predetermined intervals; an inner tube in which refrigerant flows, the inner tube being housed within the outer tube, and having a refrigerant outlet orifice for allowing the refrigerant flowing inside the inner tube to flow to the outer tube; and a structural section disposed on the inner tube or the outer tube, allowing refrigerant to flow into the inner tube. In the structural section, the refrigerant is in a state where a gas-liquid two-phase flow has not yet developed. The refrigerant outlet orifice is configured such that the angle θ from the lower end of the inner tube on a vertical line passing through the center of the inner tube to the location of the refrigerant outlet orifice, when viewed from the center of the inner tube, is set in the range of 10°≤θ≤80°. In the vertical cross-section of the inner tube at the location where the refrigerant outlet orifice is provided, there is only one refrigerant outlet orifice.

Description

Technical Field

[0001] This disclosure relates to refrigerant distributors, heat exchangers, and air conditioning units with a dual structure having inner and outer pipes. Background Technology

[0002] It is known that refrigerant distributors use a double-constructed piping system with an inner and outer tube for refrigerant distribution. In such a refrigerant distributor, a refrigerant outlet orifice, also known as a throttling orifice, is provided at the bottom of the inner tube. The refrigerant flowing out of the outlet orifice is ejected into the space between the inner and outer tubes, flows into the heat pipe from the outer tube, and thereby exchanges heat with the air (see, for example, Patent Document 1).

[0003] Patent Document 1: Japanese Patent Application Publication No. 20122475

[0004] However, in conventional refrigerant distributors, for various reasons, it is difficult to transform the refrigerant flow into an annular flow. Although it appears as an annular flow region in a typical flow pattern diagram, deviations occur in the liquid phase distribution of the vertical cross-section of the refrigerant distributor. For example, this can happen when the refrigerant inlet pipe is short, or when a heat exchanger is formed by connecting two heat exchangers with bends in the piping. Due to these deviations in liquid phase distribution, conventional refrigerant distributors result in inaccurate refrigerant distribution. Summary of the Invention

[0005] This disclosure was made in view of the above-mentioned actual situation, and its purpose is to provide a refrigerant distributor, heat exchanger, and air conditioning unit that can suppress the deviation of the liquid phase distribution of the refrigerant distributor and properly distribute the refrigerant.

[0006] The refrigerant distributor disclosed herein comprises: an outer tube in which refrigerant flows, and a plurality of heat-conducting tubes are connected to the outer tube at predetermined intervals; an inner tube in which the refrigerant flows, the inner tube being housed within the outer tube, and having a refrigerant outlet orifice for allowing the refrigerant flowing inside the inner tube to flow to the outer tube; and a structural portion disposed in the inner tube or the outer tube, allowing the refrigerant to flow into the inner tube, wherein the refrigerant is in a state where a gas-liquid two-phase flow has not yet developed in the structural portion, and the refrigerant outlet orifice is configured such that the angle θ from the lower end of the inner tube on a vertical line passing through the center of the inner tube to the location of the refrigerant outlet orifice, when viewed from the center of the inner tube, is set in the range of 10°≤θ≤80°, and only one refrigerant outlet orifice is present in the vertical cross-section of the inner tube at the location where the refrigerant outlet orifice is provided.

[0007] The refrigerant distributor disclosed herein has a structural section in the inner or outer tube where the refrigerant is in a state where the gas-liquid two-phase flow has not yet developed. The refrigerant flows into the inner tube through this structural section in this state. In the vertical cross-section of the inner tube at the location of the refrigerant outlet, there is only one refrigerant outlet. The angle θ in the refrigerant outlet, from the lower end of the inner tube on the vertical line passing through the center of the inner tube to the location of the refrigerant outlet, is set within the range of 10° ≤ θ ≤ 80°. Therefore, the refrigerant outlet is only located near the liquid surface of the refrigerant. Thus, even if the refrigerant flows into the inner tube in a state where the gas-liquid two-phase flow has not yet developed, the refrigerant can be evenly distributed into the space formed between the inner and outer tubes, enabling proper refrigerant distribution. Attached Figure Description

[0008] Figure 1 This is the refrigerant circuit diagram of the air conditioning unit involved in Implementation Method 1.

[0009] Figure 2 This is a side view of the outdoor heat exchanger of the air conditioning unit according to Embodiment 1.

[0010] Figure 3 This is a top view schematic diagram of the outdoor heat exchanger of the air conditioning unit involved in Embodiment 1.

[0011] Figure 4 This is a diagram showing the state of the refrigerant inside the inner pipe of the air conditioning unit according to Embodiment 1.

[0012] Figure 5 The air conditioning device involved in Embodiment 1 Figure 3 A vertical cross-sectional view of the refrigerant distributor of the AA line.

[0013] Figure 6 This is a vertical cross-sectional view showing the relationship between the refrigerant level in the inner tube and the refrigerant outlet hole, used to illustrate the effect of the air conditioning device according to Embodiment 1.

[0014] Figure 7 This is a diagram used to illustrate the effect of the air conditioning device according to Embodiment 1, showing the range of influence of the refrigerant outlet on the refrigerant and the flow state of the refrigerant.

[0015] Figure 8 This is a diagram illustrating the refrigerant distribution characteristics when the refrigerant outlet is located at the bottom of the inner tube, in order to explain the effect of the air conditioning device according to Embodiment 1.

[0016] Figure 9This is a vertical cross-sectional view showing the relationship between the refrigerant level in the inner tube and the refrigerant outlet hole, used to illustrate the effect of the air conditioning device according to Embodiment 1.

[0017] Figure 10 This is a diagram used to illustrate the effect of the air conditioning device according to Embodiment 1, showing the range of influence of the refrigerant outlet on the refrigerant and the flow state of the refrigerant.

[0018] Figure 11 This is a diagram illustrating the refrigerant distribution characteristics when the refrigerant outlet is located at the top of the inner tube, used to explain the effect of the air conditioning device according to Embodiment 1.

[0019] Figure 12 This is a vertical cross-sectional view showing the relationship between the refrigerant level in the inner pipe of the air conditioning device according to Embodiment 1 and the refrigerant outlet hole.

[0020] Figure 13 This is a diagram showing the range of influence of the refrigerant outlet of the air conditioning device according to Embodiment 1 on the refrigerant and its flow state.

[0021] Figure 14 This is a diagram showing the refrigerant distribution characteristics when the refrigerant outlet of the air conditioning device according to Embodiment 1 is located at the liquid level of the inner tube.

[0022] Figure 15 This is a top view of the outdoor heat exchanger of the air conditioning unit involved in Embodiment 2.

[0023] Figure 16 It is the refrigerant distributor of the air conditioning unit according to Embodiment 2. Figure 15 The vertical cross-sectional view of line AA shown.

[0024] Figure 17 It is the refrigerant distributor of the air conditioning unit according to Embodiment 2. Figure 15 The vertical cross-sectional view of the BB line shown.

[0025] Figure 18 This is a side view schematic diagram of the second outdoor heat exchanger of the air conditioning unit involved in Embodiment 3.

[0026] Figure 19 This is a side view schematic diagram of the outdoor heat exchanger involved in the first example of the air conditioning device according to Embodiment 4.

[0027] Figure 20 This is a side view schematic diagram of the outdoor heat exchanger in the second example of the air conditioning device according to Embodiment 4.

[0028] Figure 21The second example of the air conditioning device according to Embodiment 4 involves the upper outer pipe and the upper inner pipe of the outdoor heat exchanger. Figure 20 A cross-sectional view of line AA.

[0029] Figure 22 This is a side view schematic diagram of the outdoor heat exchanger involved in the third example of the air conditioning device involved in Embodiment 4.

[0030] Figure 23 This is a side view schematic diagram of the outdoor heat exchanger involved in the fourth example of the air conditioning device involved in Embodiment 4.

[0031] Figure 24 This is a diagram showing the angle of the refrigerant outlet hole in the inner pipe of the air conditioning device according to Embodiment 5.

[0032] Figure 25 It is a flow pattern line diagram (Baker line diagram) that shows the flow state of the refrigerant inside the inner tube in the distributor according to Embodiments 1 to 5, under the experimental conditions of the refrigerant conducted by the inventor.

[0033] Figure 26 This indicates that in implementation method 6, the relationship between... Figure 25 A graph of the modified Baker flow pattern under the same refrigerant inflow conditions.

[0034] Figure 27 This is a graph showing the relationship between the flow path cross-sectional area of ​​the inner tube in Embodiment 6 and the refrigerant distribution improvement rate based on the refrigerant outlet orifice.

[0035] Figure 28 This is a vertical cross-sectional view of the refrigerant distributor of the air conditioning unit according to Embodiment 7. Detailed Implementation

[0036] Hereinafter, an air conditioning unit having the refrigerant distributor according to the embodiments will be described with reference to the accompanying drawings. Furthermore, in the drawings, the same reference numerals are used to label the same components and descriptions are provided, and descriptions are repeated only where necessary. This disclosure may include all combinations of the combinable structures described in the following embodiments.

[0037] Implementation method 1.

[0038] <Air conditioning unit 100>

[0039] Figure 1 This is a refrigerant circuit diagram of the air conditioning unit 100 according to Embodiment 1. For example... Figure 1As shown, the air conditioning unit 100 includes an outdoor unit 10 and multiple indoor units 11, 12, and 13. The indoor units 11, 12, and 13 are connected in parallel. Refrigerant circulates within the outdoor unit 10 and the multiple indoor units 11, 12, and 13. The air conditioning unit 100 is a multi-split type air conditioning unit. Furthermore, Embodiment 1 does not limit the number of indoor units 11, 12, and 13 connected to the outdoor unit 10.

[0040] The air conditioning unit 100 has a refrigerant circuit consisting of a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, an expansion valve 5, an indoor heat exchanger 6, and a receiver 8, connected by refrigerant piping 26 and refrigerant piping 27. The outdoor heat exchanger 3 and the indoor heat exchanger 6 respectively use the air generated by the fan 4 and the fan 7 to exchange heat between the refrigerant flowing inside and the air.

[0041] During cooling operation, the high-temperature, high-pressure refrigerant compressed by compressor 1 flows into the outdoor heat exchanger 3 via the four-way valve 2, through the refrigerant pipe 26 connecting the four-way valve 2 and the outdoor heat exchanger 3. After exchanging heat with the air generated by fan 4, the refrigerant flows out through the refrigerant pipe 27 connecting the outdoor heat exchanger 3 and expansion valve 5. During heating operation, i.e., when the outdoor heat exchanger 3 functions as an evaporator, the refrigerant flow direction is opposite to that described above when it functions as a condenser.

[0042] <Outdoor Heat Exchanger 3>

[0043] Figure 2 This is a side view of the outdoor heat exchanger 3 of the air conditioning unit 100 according to Embodiment 1. Figure 3 This is a top view of the outdoor heat exchanger 3 of the air conditioning unit 100 according to Embodiment 1. The black arrows in the figure indicate the flow of refrigerant when it functions as an evaporator.

[0044] The outdoor heat exchanger 3 mounted on the outdoor unit 10 of the air conditioning unit 100 allows the outside air drawn in by the fan 4 through the suction port to exchange heat with the refrigerant. The outdoor heat exchanger 3 is located below the fan 4.

[0045] like Figure 2 As shown, the outdoor heat exchanger 3 includes a refrigerant distributor 30, multiple heat pipes 31, and multiple fins 32. The refrigerant distributor 30 is arranged horizontally. The multiple heat pipes 31 are spaced apart, with one end of each heat pipe 31 inserted into the refrigerant distributor 30. Fins 32 are installed on the heat pipes 31 and positioned between them. The fins 32 conduct heat to the heat pipes 31.

[0046] <Refrigerant Distributor 30>

[0047] like Figure 2 As shown, the refrigerant distributor 30 has a double-tube structure with an inner tube 33 and an outer tube 34. Multiple heat-conducting tubes 31 are connected to the outer tube 34 along its extension direction. The refrigerant flowing between the inner tube 33 and the outer tube 34 is distributed to the multiple heat-conducting tubes 31.

[0048] The inner pipe 33 extends horizontally. Refrigerant, including liquid refrigerant, flows into one end of the inner pipe 33. When the outdoor heat exchanger 3 functions as an evaporator, a cap 36 is provided at the downstream end of the inner pipe 33 through which the refrigerant flows. When the outdoor heat exchanger 3 functions as an evaporator, a refrigerant pipe 27 for the refrigeration cycle loop is connected to the upstream end of the inner pipe 33 through which the refrigerant flows.

[0049] like Figure 2 as well as Figure 3 As shown, in the inner tube 33, refrigerant outlet holes 35, also known as throttling holes, are formed at intervals between the heat-conducting pipes 31 in the tube extension direction of the inner tube 33. By providing the refrigerant outlet holes 35 between the heat-conducting pipes 31, the refrigerant distribution performance of the refrigerant distributor 30 can be improved compared to the case where the refrigerant outlet holes 35 are provided in the inner tube 33 directly below the heat-conducting pipes 31. Alternatively, the refrigerant outlet holes 35 may also be formed in the inner tube 33 directly below the heat-conducting pipes 31. Furthermore, an inlet portion 41 is provided in the inner tube 33. The inlet portion 41 has a length L, which is the length of the inlet section. Here, when the inner diameter of the inner tube 33 is set to D, L < 5D.

[0050] Figure 4 This is a diagram showing the state of the refrigerant in the inner pipe 33 of the air conditioning unit 100 according to Embodiment 1. (As shown...) Figure 4 As shown, the refrigerant exists in both gaseous and liquid phases within the inner pipe 33, which serves as a spray pipe. In Embodiment 1, a refrigerant outlet 35 is provided near the angle θ' of the liquid surface AL of the liquid refrigerant.

[0051] Figure 5 It is the air conditioning unit 100 according to embodiment 1. Figure 3 A vertical cross-sectional view of the refrigerant distributor 30 of the AA line. Figure 5 This diagram shows the refrigerant flowing in a semi-annular flow state within the inner tube 33. Figure 5 This represents an example of the angle θ' of the refrigerant surface AL in the liquid phase where the refrigerant outlet 35 is located.

[0052] Regarding the angle θ of the refrigerant outlet 35, when viewed from the center of the inner tube 33, the angle θ from the lower end of the inner tube 33 (the vertical line passing through the center of the inner tube 33) to the location of the refrigerant outlet 35 can be set within the following range:

[0053] 10°≤θ≤80°.

[0054] More specifically, the angle at which the refrigerant outlet hole 35 is set is determined by equation (1). Equation (1) is a predictive formula based on Nusselt's liquid film calculation, reflecting the inventor's experimental results.

[0055] [Formula 1]

[0056]

[0057] in,

[0058] x is the distance obtained by projecting the refrigerant outlet 35 onto a horizontal line that passes through the center of the inner tube 33 and is orthogonal to the tube's extension direction.

[0059] Ja is a Jacobi number.

[0060] Ga is the Galilean number.

[0061] Pr L It is the liquid Prandtl number.

[0062] ν L It is the dynamic viscosity coefficient of the liquid.

[0063] L is the length of the inlet section of the inner tube.

[0064] D is the inner diameter of the inner tube.

[0065] Ga=gD 3 / ν L 2 Ja = CpL / Δiv

[0066] CpL is the specific heat at constant pressure.

[0067] Δiv is latent heat.

[0068] L < 5D.

[0069] The state quantities and physical property values ​​are calculated from the pressure flowing into the refrigerant distributor 30.

[0070] Figure 6 This is a vertical cross-sectional view showing the relationship between the refrigerant level AL in the inner pipe 33 and the refrigerant outlet hole 35, used to illustrate the effect of the air conditioning device 100 according to Embodiment 1. Figure 6The text indicates that the liquid phase of the refrigerant flowing in the inner tube 33 is in a semi-annular flow. It also indicates that the refrigerant outlet 35 is located at the bottom of the inner tube 33. Figure 7 This is a diagram used to illustrate the effect of the air conditioning device 100 according to Embodiment 1, showing the range of influence of the refrigerant outlet 35 on the refrigerant and the flow state of the refrigerant. Figure 8 This is a diagram illustrating the effect of the air conditioning device 100 according to Embodiment 1, showing the refrigerant distribution characteristics when the refrigerant outlet 35 is provided at the lower part of the inner tube 33.

[0071] Figure 7 as well as Figure 8 Indicates as Figure 6 As shown, the refrigerant outlet 35 is located at the bottom of the inner tube 33. Figure 7 as well as Figure 8 In the diagram, the refrigerant outlet 35 is designated A for positions closer to the inlet 41, and G for positions farther from the inlet 41, arranged alphabetically. Figure 7 as well as Figure 8 In the diagram, the dashed lines represent the influence range of each refrigerant outlet orifice 35. At a given time, the refrigerant within the dashed lines is distributed through the refrigerant outlet orifice 35. In the case of a semi-annular refrigerant flow pattern, such as... Figure 8 As shown, the amount of liquid refrigerant distributed through the refrigerant outlet holes A to D on the upstream side is greater than the amount of liquid refrigerant distributed through the refrigerant outlet holes E to G on the downstream side.

[0072] Figure 9 This is a vertical cross-sectional view showing the relationship between the refrigerant level AL in the inner pipe 33 and the refrigerant outlet hole 35, used to illustrate the effect of the air conditioning device 100 according to Embodiment 1. Figure 9 The diagram shows the case where the liquid phase of the refrigerant flowing in the inner tube 33 is in a semi-annular flow. It also shows the case where the refrigerant outlet 35 is located at a position θ = 90° on the inner tube 33. That is, the refrigerant outlet 35 is positioned above the liquid surface AL. Figure 10 This is a diagram used to illustrate the effect of the air conditioning device 100 according to Embodiment 1, showing the range of influence of the refrigerant outlet 35 on the refrigerant and the flow state of the refrigerant. Figure 11 This is a diagram illustrating the effect of the air conditioning device 100 according to Embodiment 1, showing the refrigerant distribution characteristics when the refrigerant outlet 35 is provided at the top of the inner pipe 33. Figure 10 as well as Figure 11 Indicates as Figure 9 As shown, the refrigerant outlet 35 is positioned at θ = 90° on the inner tube 33. In the case where the refrigerant flow pattern is semi-annular, such as... Figure 11As shown, the amount of liquid refrigerant distributed in the refrigerant outlet holes A to C on the upstream side is less than the amount of liquid refrigerant distributed in the refrigerant outlet holes D to G on the downstream side.

[0073] Figure 12 This is a vertical cross-sectional view showing the relationship between the refrigerant liquid level AL in the inner pipe 33 of the air conditioning device 100 according to Embodiment 1 and the refrigerant outlet 35. Figure 12 In this context, the liquid phase of the refrigerant flowing in the inner tube 33 is in a semi-annular flow. In Embodiment 1, the refrigerant outlet 35 is located near the liquid surface AL of the inner tube 33. Only one refrigerant outlet 35 is provided in the vertical cross-section of the inner tube 33. Figure 13 This is a diagram showing the range of influence of the refrigerant outlet 35 of the air conditioning device 100 according to Embodiment 1 on the refrigerant and the flow state. Figure 14 This is a diagram showing the refrigerant distribution characteristics when the refrigerant outlet 35 of the air conditioning device 100 according to Embodiment 1 is provided at the liquid level AL of the inner tube 33. Figure 13 as well as Figure 14 Indicates as Figure 12 As shown, the refrigerant outlet 35 is located at the liquid level AL in the inner tube 33. Even in the case where the refrigerant flow pattern is semi-annular, such as Figure 14 As shown, the liquid refrigerant distribution at refrigerant outlets A to G is related to... Figure 8 as well as Figure 11 It is more balanced in comparison.

[0074] Therefore, according to the air conditioning device 100 of Embodiment 1, even when a sufficient inlet section length cannot be ensured (L < 5D), a refrigerant outlet hole 35 is provided near the liquid level AL. Thus, according to the air conditioning device 100 of Embodiment 1, the gas and liquid can be distributed more evenly in the space formed between the outer pipe 34 and the inner pipe 33. Therefore, the refrigerant distributor 30 can appropriately distribute the refrigerant.

[0075] Implementation method 2.

[0076] In Embodiment 1, the case of one outdoor heat exchanger 3 was described. In Embodiment 2, the case of the first outdoor heat exchanger 3a and the second outdoor heat exchanger 3b being connected by a bent inner pipe 33r was described.

[0077] Figure 15 This is a top view schematic diagram of the outdoor heat exchanger 3 of the air conditioning unit 100 according to Embodiment 2. Figure 15As shown, the outdoor heat exchanger 3 has a first outdoor heat exchanger 3a and a second outdoor heat exchanger 3b. The first refrigerant distributor 30a of the first outdoor heat exchanger 3a and the second refrigerant distributor 30b of the second outdoor heat exchanger 3b are connected by a curved inner tube 33r with a bend. The curved inner tube 33r connects the inner tube 33 of the first outdoor heat exchanger 3a and the inner tube 33 of the second outdoor heat exchanger 3b.

[0078] Figure 16 It is the first refrigerant distributor 30a of the air conditioning unit 100 according to Embodiment 2. Figure 15 The vertical cross-sectional view of line AA shown. Figure 16 As shown, the refrigerant flowing in the inner tube 33 of the first refrigerant distributor 30a of the first outdoor heat exchanger 3a has a semi-annular flow pattern. The angle θ1 of the refrigerant outlet 35 is, for example, θ1 = 0° at the bottom of the inner tube 33.

[0079] Figure 17 It is the first refrigerant distributor 30a of the air conditioning unit 100 according to Embodiment 2. Figure 15 The vertical cross-sectional view of the BB line shown. Figure 17 As shown, the flow pattern of the refrigerant flowing in the inner tube 33 of the second refrigerant distributor 30b of the second outdoor heat exchanger 3b is called a separated flow. The angle θ2 of the refrigerant outlet orifice 35 is, for example, θ2 = |45°|, a horizontal direction orthogonal to the tube extension direction through the center of the inner tube 33.

[0080] The angle θ2 of the refrigerant outlet hole 35 of the second refrigerant distributor 30b is in the range of -180° to 180°, including an angle larger than the angle θ1 of the refrigerant outlet hole 35 of the first refrigerant distributor 30a (θ2 > θ1).

[0081] According to the air conditioning device 100 of Embodiment 2, the refrigerant flowing in the inner pipe 33 of the first refrigerant distributor 30a before passing through the curved inner pipe 33r has a semi-annular flow pattern. The refrigerant flowing in the inner pipe 33 of the second refrigerant distributor 30b after passing through the curved inner pipe 33r has a separated flow pattern. Therefore, as Figure 17 As shown, the refrigerant liquid level AL rises, and the refrigerant distribution performance deteriorates. In Embodiment 2, the angle θ2 of the refrigerant outlet orifice 35 of the second refrigerant distributor 30b is larger than the angle θ1 of the refrigerant outlet orifice 35 of the first refrigerant distributor 30a. This improves the refrigerant distribution performance of both the first refrigerant distributor 30a and the second refrigerant distributor 30b.

[0082] In addition, the bent inner tube 33r can also be an L-shaped pipe fitting (elbow). Alternatively, the outer tube 34 of the first refrigerant distributor 30a can be bent to form the outer tube 34.

[0083] Implementation method 3.

[0084] The outdoor heat exchanger 3 in embodiment 3 and Figure 15 Similarly, Embodiment 2 shown employs a structure consisting of a first outdoor heat exchanger 3a and a second outdoor heat exchanger 3b. In Embodiment 3, the diameter of the inner tube 33 of the second outdoor heat exchanger 3b is reduced towards the terminal portion.

[0085] Figure 18 This is a side view schematic diagram of the second outdoor heat exchanger 3b of the air conditioning unit 100 according to Embodiment 3. Figure 18 As shown, the second outdoor heat exchanger 3b has inner tubes 33a and 33b. Figure 15 As shown, the inner tube 33 of the first outdoor heat exchanger 3a is connected via a bent inner tube 33r (see reference). Figure 15 ) and the inner tube 33a of the second outdoor heat exchanger 3b (refer to Figure 15 The inner diameter of the inner tube 33a of the second outdoor heat exchanger 3b is the same as the inner diameter of the inner tube 33 of the first outdoor heat exchanger 3a. The inner tube 33a is connected to the inner tube 33b. The inner diameter of the inner tube 33b is smaller than the inner diameter of the inner tube 33a. A cover 36 is provided at the end of the inner tube 33b. That is, the inner diameter of the end portion of the inner tube 33b of the second outdoor heat exchanger 3b with the cover 36 is smaller than the inner diameter of the beginning portion of the inner tube 33a of the second heat exchanger connected to the curved inner tube 33r.

[0086] According to the air conditioning unit 100 of Embodiment 3, the refrigerant flow rate in the terminal section of the second refrigerant distributor 30b of the second outdoor heat exchanger 3b is reduced, which can suppress the change of the flow pattern from a semi-annular flow to a separated flow. Therefore, the flow robustness of the refrigerant distribution characteristics can be improved.

[0087] Furthermore, in Embodiment 3, the case where the second outdoor heat exchanger 3b has an inner pipe 33a and an inner pipe 33b is described, but the inner pipe 33 of the second outdoor heat exchanger 3b may also be a pipe whose inner diameter gradually decreases from the beginning end toward the end end.

[0088] Implementation method 4.

[0089] In embodiment 4, a structural part C is provided upstream of the inner pipe 33, where the refrigerant flowing in the inner pipe 33 is in a state where the gas-liquid two-phase flow has not yet developed. Here, "state where the gas-liquid two-phase flow has not yet developed" means that the refrigerant flowing in the inner pipe 33 is not in a gas-liquid two-phase flow state, but in a laminar flow state.

[0090] <The First Example of a Structural Section>

[0091] Figure 19 This is a side view of the outdoor heat exchanger 3 in the first example of the air conditioning unit 100 according to Embodiment 4. Figure 19 This is a diagram showing the structure C1 of the first example of the refrigerant distributor 30 of the air conditioning device 100 according to Embodiment 4.

[0092] In addition, Figure 19 In the lower inner tube 33_1, a refrigerant outlet hole 35 (not shown) is provided at the position described in Embodiment 1. Furthermore, the connection relationship between the plurality of heat-conducting pipes 31 and the lower outer tube 34_1 is the same as in Embodiment 1. An upper outer tube 34 is provided above the plurality of heat-conducting pipes 31 and the fins 32 (not shown). The connection relationship between the upper outer tube 34 and the plurality of heat-conducting pipes 31 is the same as the connection relationship between the lower outer tube 34_1 and the plurality of heat-conducting pipes 31.

[0093] An outflow pipe 42 is provided at the refrigerant outflow end of the upper outer pipe 34, and the outflow pipe 42 has a smaller diameter than the upper outer pipe 34.

[0094] like Figure 19 As shown, the lower inner tube 33_1 is housed within the lower outer tube 34_1, and the upstream side extends further than the lower outer tube 34_1. The extended portion of the lower inner tube 33_1 is a straight inlet section 41, which serves as the inlet section for the refrigerant flowing into the lower outer tube 34_1. The inlet section 41, which is the extended portion of the lower inner tube 33_1, is also referred to as the structural section C1.

[0095] When the inner diameter of the inlet section 41 is set to D and the length of the inlet section 41 is set to L, L < 10 × D. More preferably, L < 5 × D.

[0096] The refrigerant passing through this structure C1 is in a state where the gas-liquid two-phase flow has not yet developed, and flows into the lower inner pipe 33_1. Then, the refrigerant in the state where the gas-liquid two-phase flow has not yet developed flows out from the lower inner pipe 33_1 through the refrigerant outlet hole 35 (not shown) and out to the lower outer pipe 34_1. The refrigerant flowing out to the lower outer pipe 34_1 flows into the upper outer pipe 34 through multiple heat-conducting pipes 31. The refrigerant flowing into the upper outer pipe 34 flows into the outlet pipe 42 and flows out from the outlet pipe 42 to the outside of the outdoor heat exchanger 3.

[0097] Methods for estimating refrigerant flow patterns include flow pattern diagrams such as Baker's diagrams. These flow pattern diagrams mostly represent the fully developed state of gas-liquid flow; in other words, they represent the flow pattern under conditions where a sufficient inlet length is provided.

[0098] Based on the inventors' latest refrigerant visualization experiments, it has been newly determined that the flow pattern calculated using Baker's diagrams and other methods when installed on an actual machine differs from the actual flow pattern due to the lack of flow development. Specifically, even in the case of annular flow patterns on the flow pattern diagrams, laminar and wavy flow patterns are often confirmed. Based on the inventors' experimental results, this trend is more pronounced when the inlet length of the lower inner tube 33_1 is in the range of L < 10 × D, and particularly significant when L < 5 D. Therefore, when there is insufficient inlet length upstream of the lower inner tube 33_1, the refrigerant outlet 35 of the lower inner tube 33_1 is positioned near the interface of laminar or wavy flow (θ = 10° to 80°).

[0099] (Effect)

[0100] Therefore, according to the refrigerant distributor 30 having the structure C1 of the air conditioning device 100 according to Embodiment 4, by providing the structure C1 on the lower inner pipe 33_1, the gas-liquid two-phase flow can be evenly distributed, thereby improving the distribution performance.

[0101] <The Second Example of a Structural Section>

[0102] Figure 20 This is a side view of the outdoor heat exchanger 3 in the second example of the air conditioning unit 100 according to Embodiment 4. Figure 20 This is a diagram showing the structure C2 of a second example of the refrigerant distributor 30 in the air conditioning device 100 according to Embodiment 4.

[0103] exist Figure 20 As shown, in order to increase the refrigerant flow rate and improve performance in the outdoor heat exchanger 3, a partition 51_1 is provided inside the lower outer pipe 34_1, and a partition 51_2 is provided inside the upper outer pipe 34_2.

[0104] like Figure 20As shown, a separator 51_1 is provided inside the lower outer tube 34_1. The separator 51_1 divides the interior of the lower outer tube 34_1 into a lower outer tube 34_1_1 and a lower outer tube 34_1_2 along the axial direction of the outer tube 34_1. An inflow portion 41 is provided at the refrigerant inflow end of the lower outer tube 34_1_1, and this inflow portion 41 has a diameter smaller than that of the lower outer tube 34_1_1. An outflow pipe 42 is connected to the outflow side of the lower outer tube 34_1_2, and this outflow pipe 42 has a diameter smaller than that of the lower outer tube 34_1_2.

[0105] exist Figure 20 In this embodiment, the connection relationship between the multiple heat pipes 31 and the lower outer tube 34_1 is the same as in Embodiment 1. An upper outer tube 34_2 and an upper inner tube 33_2 are provided above the multiple heat pipes 31 and the fins 32 (not shown). The connection relationship between the upper outer tube 34_2 and the multiple heat pipes 31 is the same as the connection relationship between the lower outer tube 34_1 and the multiple heat pipes 31.

[0106] The upper outer tube 34_2 houses the upper inner tube 33_2. Similar to Embodiment 1, a refrigerant outlet 35 is provided in the upper inner tube 33_2. A separator 51_2 is provided inside the upper outer tube 34_2. The separator 51_2 is located above the separator 51_1 and divides the interior of the upper outer tube 34_2 into an upper outer tube 34_2_1 and an upper outer tube 34_2_2 along the axial direction of the outer tube 24_2. Specifically, the separator 51_2 separates the inner circumference of the upper outer tube 34_2 from the upper inner tube 33_2 along the axial direction of the outer tube 24_2.

[0107] The upper outer tube 34_2 extends further than the upper inner tube 33_2. The interior of the upper outer tube 34_2_1 forms a confluence space S_1. Multiple heat-conducting pipes 31 are connected to the confluence space S_1, and the refrigerant passing through the inlet 41, the lower outer tube 34_1_1, and the multiple heat-conducting pipes 31 flows together in the confluence space S_1.

[0108] The confluence space S_1 is also called the structural section C2. The refrigerant confluencing in the confluence space S_1 flows into the inner pipe 33_2 on the upper side. In addition, a portion of the refrigerant confluencing in the confluence space S_1 is deflected by the separator 51_2 and flows into the inner pipe 33_2 on the upper side.

[0109] For the merging space S_1, if the flow path cross-sectional area of ​​the merging space S_1 is set to A1, and the flow path cross-sectional area of ​​the upper inner tube 33_2 is set to AS,

[0110] A1 > AS.

[0111] With this structure, when the refrigerant flows from the confluence space S_1 with a large flow path cross-sectional area to the inner tube 33_2 on the upper side with a small flow path cross-sectional area, the gas-liquid two-phase flow is reduced, but it becomes a state where the gas-liquid two-phase flow has not developed in the confluence space S_1.

[0112] Figure 21 The outer pipe 34_2_2 on the upper side and the inner pipe 33_2 on the upper side of the outdoor heat exchanger 3 involved in the second example of the air conditioning device 100 according to Embodiment 4 are along the... Figure 20 A cross-sectional view of line AA.

[0113] like Figure 21 As shown, in the upper inner tube 33_2, and... Figure 5 The illustrated embodiment 1 also shows an example where the refrigerant outlet 35 is set at the angle θ' of the liquid level AL in the liquid phase refrigerant.

[0114] The angle θ' of the refrigerant outlet hole 35 is the angle observed from the center of the upper inner tube 33_2, from the lower end of the upper inner tube 33_2 along a vertical line passing through the center of the upper inner tube 33_2 to the location of the refrigerant outlet hole 35. It can be set within the following range:

[0115] 10°≤θ'≤80°.

[0116] exist Figure 20 In the middle, the refrigerant flowing out of the refrigerant outlet 35 of the upper inner pipe 33_2 passes sequentially through the upper outer pipe 34_2_2 and multiple heat conduction pipes 31, and flows into the lower outer pipe 34_1_2. The refrigerant flowing into the lower outer pipe 34_1_2 flows into the outlet piping 42 and flows out to the outside of the outdoor heat exchanger 3.

[0117] (Effect)

[0118] According to the refrigerant distributor 30 having the structural part C2 of the air conditioning device 100 according to Embodiment 4, the structural part C2 is provided on the upper outer pipe 34_2. As a result, the flow path cross-sectional area A1 of the confluence space S_1 is different from the flow path cross-sectional area AS of the upper inner pipe 33_2, and therefore, gas-liquid two-phase flow does not develop. Consequently, a region where gas-liquid two-phase flow does not develop is formed upstream of the upper inner pipe 33_2. In this case, the position of the refrigerant outlet 35 of the upper inner pipe 33_2 is located near the interface of laminar or wavy flow (θ = 10° to 80°).

[0119] Therefore, the refrigerant distributor 30, which has the structure C2 of the air conditioning device 100 according to Embodiment 4, can uniformly distribute the gas-liquid two-phase flow, thereby improving the distribution performance.

[0120] <The Third Example of the Construction Department>

[0121] Figure 22 This is a side view of the outdoor heat exchanger 3 in the third example of the air conditioning unit 100 according to Embodiment 4. Figure 22 This is a diagram showing the structure C3 of the refrigerant distributor 30 in the third example of the air conditioning device 100 according to Embodiment 4.

[0122] like Figure 22 As shown, a partition 61 is provided inside the lower outer tube 34_1. The partition 61 divides the lower outer tube 34_1 into a lower outer tube 34_1_1 and a lower outer tube 34_1_2. Specifically, the partition 61 separates the inner circumference of the lower outer tube 34_1 from the lower inner tube 33_1.

[0123] The lower outer tube 34_1_1 extends further than the lower inner tube 33_1. The lower surface of the lower outer tube 34_1_1 has an opening (not shown). A refrigerant inlet tube 62 is connected to the opening.

[0124] The interior of the lower outer pipe 34_1 forms the inflow space S_2. Refrigerant flows into the inflow space S_2 from the inflow pipe 62.

[0125] The inflow space S_2 is also called the structural section C3. The refrigerant flowing into the inflow space S_2 flows into the inner pipe 33_1 on the lower side.

[0126] For the inflow space S_2, if the cross-sectional area of ​​the flow path in the inflow space S_2 is set to A2, and the cross-sectional area of ​​the flow path in the lower inner tube 33_1 is set to AS,

[0127] A2 > AS.

[0128] According to this structure, when the refrigerant flows from the inflow space S_2 with a large flow path cross-sectional area to the inner tube 33_1 with a small flow path cross-sectional area on the tongue side, the gas-liquid two-phase flow is reduced, but it becomes a state where the gas-liquid two-phase flow has not developed in the inflow space S_2.

[0129] exist Figure 22 In this embodiment, the connection relationship between the multiple heat pipes 31 and the lower outer tube 34_1 is the same as in Embodiment 1. An upper outer tube 34_2 is provided above the multiple heat pipes 31 and the fins 32 (not shown). The connection relationship between the upper outer tube 34_2 and the multiple heat pipes 31 is the same as the connection relationship between the lower outer tube 34_1 and the multiple heat pipes 31.

[0130] An outlet pipe 42 is provided at the end of the refrigerant outlet side of the upper outer pipe 34_2, and the outlet pipe 42 has a smaller diameter than the upper outer pipe 34_2.

[0131] The refrigerant flowing into the lower inner pipe 33_1 exits through a refrigerant outlet hole 35 (not shown) and flows into the lower outer pipe 34_1. The refrigerant flowing into the lower outer pipe 34_1 flows into the upper outer pipe 34_2 through multiple heat-conducting pipes 31. The refrigerant flowing into the upper outer pipe 34_2 flows into the outlet piping 42 and then outwards towards the outdoor heat exchanger 3.

[0132] In this case, the refrigerant outlet hole 35 of the lower inner tube 33_1 is positioned near the interface of laminar or wavy flow (θ = 10° to 80°).

[0133] In addition, Figure 22 The diagram shows the case where the refrigerant inlet pipe 62 is located on the lower surface of the lower outer pipe 34_1_1, but the number of refrigerant inlet pipes 62 is not limited to one. Alternatively, the refrigerant inlet pipe 62 can also be installed on the upper surface or side surface of the lower outer pipe 34_1_1.

[0134] (Effect)

[0135] The refrigerant distributor 30 of the air conditioning unit 100 according to Embodiment 4 has a structural portion C3, which is a portion in which the lower outer tube 34_1_1 extends further than the lower inner tube 33_1, and the structural portion C3 has an inflow space S_2. Inside the lower outer tube 34_1, the lower inner tube 33_1 is housed in and protected by the lower outer tube 34_1. Therefore, it is not necessary to thicken the lower inner tube 33_1 to ensure strength, and it is possible to achieve a thinner wall and space saving for the lower inner tube 33_1. In addition, since the lower inner tube 33_1 is not exposed to the outside, the wall thickness of the lower inner tube 33_1 can be reduced.

[0136] According to the refrigerant distributor 30 having the structural part C3 of the air conditioning device 100 according to Embodiment 4, by providing the structural part C3 on the lower outer pipe 34_1_1, the gas-liquid two-phase flow is in a state where it has not developed, thereby enabling uniform distribution of the gas-liquid two-phase flow in the inner pipe 33_1. As a result, the distribution performance of the refrigerant distributor 30 is improved.

[0137] In addition, by connecting the refrigerant inlet pipe 62 to the lower outer pipe 34_1_1, the increase in piping space caused by the piping configuration such as the refrigerant inlet pipe 62 can be suppressed, and correspondingly, the installability of the outdoor heat exchanger 3 can be improved.

[0138] <The Fourth Example of the Construction Department>

[0139] Figure 23 This is a side view of the outdoor heat exchanger 3 in the fourth example of the air conditioning unit 100 according to Embodiment 4. Figure 23This is a diagram showing the structure C4 of the refrigerant distributor 30 in the air conditioning device 100 according to Embodiment 4.

[0140] In addition, Figure 23 In the lower inner tube 33_1, a refrigerant outlet hole 35 (not shown) is provided at the position described in Embodiment 1. Furthermore, the connection relationship between the plurality of heat-conducting pipes 31 and the lower outer tube 34_1 is the same as in Embodiment 1. An upper outer tube 34_2 is provided above the plurality of heat-conducting pipes 31 and the fins 32 (not shown). The connection relationship between the upper outer tube 34_2 and the plurality of heat-conducting pipes 31 is the same as the connection relationship between the lower outer tube 34_1 and the plurality of heat-conducting pipes 31.

[0141] An outflow pipe 42 is provided at the refrigerant outflow end of the upper outer pipe 34_2, and the outflow pipe 42 has a smaller diameter than the upper outer pipe 34_2.

[0142] like Figure 23 As shown, the lower inner tube 33_1 is housed within the lower outer tube 34_1, and the upstream side extends further than the lower outer tube 34_1. The extended portion of the lower inner tube 33_1 is straight. Furthermore, a curved inflow pipe 63 is provided upstream of the straight portion of the extended lower inner tube 33_1. The curved inflow pipe 63 is also referred to as structural part C4.

[0143] With the inner diameter of the flow path of the curved inlet pipe 63 set as DR, and the length of the straight portion of the lower inner pipe 33_1 that extends further than the outer pipe 34_1_2 set as L2,

[0144] L2 < 5 × DR.

[0145] The refrigerant in this structure C4 is in a state where the gas-liquid two-phase flow has not yet developed. Then, the refrigerant in this undeveloped gas-liquid two-phase flow state flows into the lower inner pipe 33_1. The refrigerant flowing into the lower inner pipe 33_1 flows out through the refrigerant outlet hole 35 (not shown) and into the lower outer pipe 34_1. The refrigerant flowing out of the lower outer pipe 34_1 flows into the upper outer pipe 34_2 through multiple heat-conducting pipes 31. The refrigerant flowing into the upper outer pipe 34_2 flows into the outlet pipe 42 and outwards towards the outdoor heat exchanger 3.

[0146] In this case, the refrigerant outlet 35 of the lower inner tube 33_1 is positioned near the interface of laminar or wavy flow (θ = 10° to 80°).

[0147] In addition, Figure 23The diagram shows a case where a curved inflow pipe 63 is provided on the lower inner tube 33_1, but a portion of the lower inner tube 33_1 can also be bent to form the curved inflow pipe 63.

[0148] (Effect)

[0149] According to the refrigerant distributor 30 of the air conditioning device 100 according to Embodiment 4, by providing a curved inflow pipe 63, the gas-liquid refrigerant flowing in the curved inflow pipe 63 is subjected to centrifugal force. As a result, the gas-liquid two-phase flow of refrigerant flowing in the curved inflow pipe 63 becomes an undeveloped state.

[0150] Therefore, according to the refrigerant distributor 30 having the structure C4 of the air conditioning device 100 according to Embodiment 4, by providing the structure C4 on the lower outer pipe 34_1, the gas-liquid two-phase flow can be evenly distributed, thereby improving the distribution performance.

[0151] Implementation method 5.

[0152] By providing structural sections C1 to C4 as described in Embodiment 4, the refrigerant flowing into the inner pipe 33 is in a state where the gas-liquid two-phase flow has not yet developed. In this case, based on the inventor's analysis, a more suitable angle for the refrigerant outlet orifice 35 was determined. In Embodiment 5, in the case where the gas-liquid two-phase flow has not yet developed, a more suitable angle for the refrigerant outlet orifice 35 is determined. Define it. Angle. It is the angle measured from the center of the inner tube 33 when viewed from the bottom of the inner tube 33 along a vertical line passing through the center of the inner tube 33 to the location of the refrigerant outlet 35.

[0153] Figure 24 This indicates the angle of the refrigerant outlet 35 in the inner pipe 33 of the air conditioning unit 100 according to Embodiment 5. The image.

[0154] exist Figure 24 middle,

[0155] The optimal angle for the refrigerant outlet is 35 degrees.

[0156] It is the liquid surface angle assuming the refrigerant's gas-liquid slip ratio is 1 and the gas-liquid interface is planar and horizontal.

[0157] The wetting boundary angle in the pipe circumferential direction is used in the prediction of the slip ratio of the refrigerant gas and liquid, as well as the evaporation transfer rate due to inertial forces.

[0158] AS is the flow path cross-sectional area of ​​inner tube 33.

[0159] In When the liquid level angle is defined as the flow pattern, the angle of the refrigerant outlet orifice is 35 degrees. for

[0160]

[0161] here, Using equations (2) to (4) proposed by Mori et al. for predicting the evaporative heat transfer rate of horizontal smooth tubes, the calculations were performed by equations (5) and (6).

[0162] [Equation 2]

[0163]

[0164] [Formula 3]

[0165]

[0166] [Formula 4]

[0167]

[0168] [Formula 5]

[0169]

[0170] [Formula 6]

[0171]

[0172] Here, the variables in the formula are as follows: for refrigerant dryness, density, mass velocity, and latent heat, the value at the inlet of inner tube 33 is used as the representative value. Furthermore, the heat flow rate in inner tube 33 is set to a sufficiently small value, q = 0.001. Additionally, when the refrigerant mass flow rate is defined as M [kg / h] and the inner diameter of inner tube 33 is defined as d [m], the mass velocity is given by G = (M × 3600) / {(D / 2)}. 2 The definition of π is as follows. Furthermore, refrigerant state parameters such as density and latent heat of vaporization can be calculated using general property tables and property calculation software such as Refprop.

[0173] x: Refrigerant dryness [−],

[0174] ρ G Refrigerant gas density [kg / m³] 3 ],

[0175] ρ L Refrigerant liquid density [kg / m³] 3],

[0176] G: Mass velocity [kg / (m)] 2 s)],

[0177] D: Inner diameter of inner tube 33 [m]

[0178] g: acceleration due to gravity [m / s²] 2 ],

[0179] Δh G Latent heat of vaporization [kJ / kg]

[0180] q: Average heat flux velocity around the inner surface of the pipe [kW / m] 2 ].

[0181] The wetting boundary angle in the pipe circumferential direction calculated based on the formula of Sen et al. The formula is derived analytically from a database of heat transfer rate measurements. Since the heat transfer rate contributes significantly to the heat transfer rate in very thin liquid film regions, it is assumed that the boundary angle of these very thin regions is taken into account. On the other hand, the optimal distribution angle of the refrigerant outlet orifice 35 is used to achieve proper distribution in refrigerant distribution. It should be the part that is a certain degree thicker than the liquid film, that is... For a smaller angle. Additionally, this optimally allocated angle... like Figure 24 As shown, the liquid surface angle is assumed to exist under the condition that the gas-liquid slip ratio is 1, and the gas-liquid interface is planar and horizontal. A large angle.

[0182] Based on the inventor's analysis of formulas (2) to (6) and the comparison results of the refrigerant visualization experiment, it can be seen that, from the perspective of optimal distribution... Generally consistent. Furthermore, while the liquid level angle is affected by refrigerant flow rate, dryness, and the gas-liquid density ratio, the influence of dryness, in particular, is dominant. The range of 0.05 to 0.80, which is frequently observed due to the dryness of the evaporator inlet in typical air conditioning equipment, is assumed to represent the maximum flow rate under typical heating rated operation conditions. In this case, the optimal distribution angle exists in the range of 80° to 10°, indicating that the higher the dryness, the smaller the optimal distribution angle.

[0183] Furthermore, equations (6) and (7) were obtained by the inventor through analysis using equations (2) to (6). as well as The predictive formula. In equations (6) and (7), the dominant shape parameter of the inner tube 33, i.e., the flow path cross-sectional area AS[mm] of the inner tube 33, is represented by the refrigerant flow state under normal heating rated operation in the air conditioner as a representative condition. 2 From the perspective of optimal allocation The relationship. By optimizing the allocation angle. satisfy It can improve the distribution performance of inner tube 33.

[0184] [Formula 7]

[0185] φ DO = (-0.0408×AS+74.124)×0.62 …(7)

[0186] [Formula 8]

[0187] φ DS = (-0.0408×AS+74.124)×1.2 …(8)

[0188] Therefore, according to the refrigerant distributor 30 of the air conditioning device 100 according to Embodiment 5, the angle of the refrigerant outlet 35 can be adjusted. By placing it in a more appropriate location, the refrigerant can be distributed more evenly.

[0189] Implementation method 6.

[0190] Figure 25 It is a flow pattern line diagram (Baker line diagram) that shows the flow state of the refrigerant inside the inner tube 33 in the distributor according to embodiments 1 to 5, under the inventor's experimental conditions for refrigerant.

[0191] The inventors attempted to suppress the deviation of the liquid phase caused by gravity inside the inner tube 33 by setting the inner diameter of the inner tube 33 in a way that forms a flow state such as an annular flow or annular spray flow on the Baker line diagram.

[0192] However, as Figure 25 As shown, even under conditions where the flow pattern line diagram shows annular flow and annular spray flow, the refrigerant can be visualized through experiments to confirm that the refrigerant actually flows in a wavy or laminar flow.

[0193] This is inferred because flow pattern diagrams such as the Baker diagram are mostly constructed based on water-air experiments with sufficient inlet length. According to the inventors' refrigerant visualization experiments, under the condition of maximum refrigerant flow in the heat exchanger, the inner diameter of the inner tube 33, which will encompass annular flow, annular spray flow, and slug flow on the Baker diagram, is defined as D.A When [m], it can be known that if the inner diameter D[m] of inner tube 33 is D≥D A Within a range of 6, the flow is more likely to be undeveloped and become laminar.

[0194] As a result, by modifying the Baker flow pattern line diagram, the inner diameter D of the inner tube 33 is set to D. A / 6, Based on refrigerant visualization experiments, it was clarified that the actual flow pattern can be roughly predicted.

[0195] Figure 26 This indicates that in implementation method 6, the relationship between... Figure 25 A plot of the modified Baker flow pattern line graph under the same refrigerant inflow conditions. Figure 26 In the middle, the inner diameter D of the inner tube 33 is set as D. A / 6. For example... Figure 26 As shown, this confirms that in Figure 25 The Baker flow pattern line graph shown depicts annular flow and annular spray flow under the condition of laminar flow. The actual refrigerant flow pattern observed through refrigerant visualization is similar to... Figure 26 The flow patterns of the refrigerants shown are largely consistent. Therefore, when D≥D A In the inner diameter of the inner tube 33 of / 6, similarly to embodiments 1 to 5, the refrigerant flow inside becomes an undeveloped flow, becoming a laminar flow. Therefore, for example, by positioning the refrigerant outlet hole 35 of the lower inner tube 33_1 near the interface of laminar or wavy flow (θ = 10° to 80°), the distribution performance of the gas-liquid two-phase flow can be improved.

[0196] In addition, the horizontal axis of the Baker line chart is The vertical axis is G G / λ, G G =W G / A m G L =W L / A m W G =W×x, W L =W×(1-x), A m =(D / 2) 2 ×π.

[0197] here,

[0198] G L Liquid phase mass velocity [kg / m] 2 s],

[0199] G G Gas phase mass velocity [kg / m] 2 s],

[0200] W L Liquid phase mass flow rate [kg / s]

[0201] W G Gas phase mass flow rate [kg / s]

[0202] A m : Cross-sectional area of ​​the flow path in the inner tube 33 [m²] 2 ],

[0203] x: Dryness degree [−],

[0204] ρ: Density [kg / m³] 3 ],

[0205] μ: viscosity coefficient [Pa·s],

[0206] σ: Surface tension [N / m].

[0207] [Formula 9]

[0208]

[0209] [Formula 10]

[0210]

[0211] The values ​​represented by the subscripts A and W are the physical properties of air and water at atmospheric pressure and 20°C. σ w It is the surface tension of the air-water system in this state.

[0212] Furthermore, according to the refrigerant visualization experiment conducted by the inventors using common Freon refrigerant, the cross-sectional area of ​​the flow path in the inner tube 33 is AS = 31.6 mm². 2 ~201.1mm 2 In most cases, under the flow conditions, the refrigerant becomes a laminar flow. If the angle of the refrigerant outlet hole 35 is located near the liquid surface AL (θ = 10° to 80°) as shown in Embodiments 1 to 5, the effect of improving the distribution deviation is particularly high.

[0213] Figure 27 This is a graph showing the relationship between the flow path cross-sectional area AS of the inner tube 33 in Embodiment 6 and the refrigerant distribution improvement rate based on the refrigerant outlet hole 35. (See figure) Figure 27 As shown, in the range 0 < AS < 31.6 mm 2 In region R_1, the refrigerant flow pattern tends to transform into an annular flow in most cases, so the improvement effect of distribution based on the angle of the refrigerant outlet 35 is small.

[0214] On the other hand, at 31.6mm 2 ≤AS≤201.1mm 2In region R_2, where the flow pattern has not developed and becomes wavy or laminar, the distribution improvement effect is significant. When AS > 201.1 mm 2 In region R_3, because the cross-sectional area of ​​the inner pipe 33 is larger than that of the heat exchanger used in a typical air conditioner, the inertial force is small, and the distribution tends to deteriorate, thus reducing the distribution improvement effect.

[0215] Implementation method 7.

[0216] Figure 28 This is a vertical cross-sectional view of the refrigerant distributor 30 of the air conditioning unit 100 according to Embodiment 7.

[0217] In Embodiments 1 to 6, the orientation of the refrigerant outlet orifice 35 is not specifically defined; by positioning the refrigerant outlet orifice 35 near the liquid surface AL, an improved distribution effect is achieved. In contrast, in Embodiment 7, when the refrigerant distributor 30 is installed in the heat exchanger, the orientation of the refrigerant outlet orifice 35, i.e., the opening direction of the refrigerant outlet orifice 35, is set as follows: Specifically, when the refrigerant distributor 30 is installed in the heat exchanger, the refrigerant outlet orifice 35 is positioned on the upwind side of the refrigerant distributor 30, and near the liquid surface AL (θ = 10° to 80°). With this configuration, a larger amount of liquid refrigerant can be distributed to areas with large temperature differences in the flat tube.

[0218] The embodiments are presented by way of example and are not intended to limit the claims. The embodiments can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the embodiments. These embodiments and their variations are included within the scope and spirit of the embodiments.

[0219] Explanation of reference numerals in the attached figures

[0220] 1... Compressor; 2... Four-way valve; 3... Outdoor heat exchanger; 3a... First outdoor heat exchanger; 3b... Second outdoor heat exchanger; 4... Fan; 5... Expansion valve; 6... Indoor heat exchanger; 7... Fan; 8... Receiver; 10... Outdoor unit; 11, 12, 13... Indoor unit; 26, 27... Refrigerant piping; 30... Refrigerant distributor; 30a... First refrigerant distributor; 30b... Second refrigerant distributor; 31... Heat pipe; 32... Fins; 33, 33a, 33b, 33_2... Inner tube; 33r... Bent inner tube; 34, 34_1, 34_1_1, 34 _1_2、34_2_1、34_2_2...Outer pipe; 35...Refrigerant outlet; 36...Cover; 41...Inlet section; 42...Outlet piping; 51_1、51_2、61...Separator; 62...Refrigerant inlet pipe; 63...Bent inlet pipe; 100...Air conditioning unit; AL...Liquid level; C、C1~C4...Structure section; L...Length of extended inner pipe; D...Inner diameter of extended inner pipe; A1...Cross-sectional area of ​​the confluence space; A2...Cross-sectional area of ​​the inlet space; AS...Cross-sectional area of ​​the inner pipe; DR...Inner diameter of the bent inlet pipe; L2...Length of the straight section of the extended inner pipe; ... liquid level angle; ...liquid surface angle; θ, θ1... Angle of refrigerant outlet hole; θ'... Angle of liquid surface; R_1, R_2, R_3... Regions; S_1... Confluence space; S_2... Inflow space.

Claims

1. A refrigerant distributor, characterized in that, have: An outer tube, in which refrigerant flows, and a plurality of heat-conducting tubes are connected at predetermined intervals to the outer tube; An inner tube, in which the refrigerant flows, is housed within an outer tube and has a refrigerant outlet for allowing the refrigerant flowing inside the inner tube to flow into the outer tube; and A structural section, disposed within the inner or outer pipe, allows the refrigerant to flow into the inner pipe. Within this structural section, the refrigerant is in a state where a gas-liquid two-phase flow has not yet developed. The refrigerant outlet is configured such that the angle θ, from the lower end of the inner tube on a vertical line passing through the center of the inner tube to the location of the refrigerant outlet, is set in the range of 10°≤θ≤80° when viewed from the center of the inner tube. In the vertical cross-section of the inner tube at the location where the refrigerant outlet hole is provided, there is only one refrigerant outlet hole. The angle θ of the refrigerant outlet hole is obtained from equation (1). [Formula 1] in, x is the distance obtained by projecting the refrigerant outlet hole onto a horizontal line that passes through the center of the inner tube and is orthogonal to the direction of tube extension. Ja is a Jacobi number. Ga is the Galilean number. Pr L It is the liquid Prandtl number. ν L It is the dynamic viscosity coefficient of the liquid. L is the length of the inlet section of the inner tube. D is the inner diameter of the inner tube. Ga=gD 3 / n L 2 ,Ja=CpL / Δiv, CpL is the specific heat at constant pressure. Δiv is latent heat. L < 5D.

2. A refrigerant distributor, characterized in that, have: An outer tube, in which refrigerant flows, and a plurality of heat-conducting tubes are connected at predetermined intervals to the outer tube; An inner tube, in which the refrigerant flows, is housed within an outer tube and has a refrigerant outlet for allowing the refrigerant flowing inside the inner tube to flow into the outer tube; and A structural section, disposed within the inner or outer pipe, allows the refrigerant to flow into the inner pipe. Within this structural section, the refrigerant is in a state where a gas-liquid two-phase flow has not yet developed. The refrigerant outlet is configured such that, assuming the refrigerant's gas-liquid slip ratio is 1 and the gas-liquid interface is planar and horizontal, the liquid surface angle is defined as φ. D0 , The liquid level angle of the refrigerant is defined as φ. DS , The cross-sectional area of ​​the flow path of the inner tube is defined as AS[mm]. 2 In the case of ], The angle θ, measured from the bottom of the inner tube on a vertical line passing through the center of the inner tube to the location of the refrigerant outlet, satisfies φ when viewed from the center of the inner tube. D0 <θ<φ DS ,in, f D0 =(-0.0408×AS+74.124)×0.62, f DS = (-0.0408×AS+74.124)×1.

2.

3. The refrigerant distributor according to claim 2, characterized in that, The angle θ of the refrigerant outlet hole is obtained from equation (1). [Formula 1] in, x is the distance obtained by projecting the refrigerant outlet hole onto a horizontal line that passes through the center of the inner tube and is orthogonal to the direction of tube extension. Ja is a Jacobi number. Ga is the Galilean number. Pr L It is the liquid Prandtl number. ν L It is the dynamic viscosity coefficient of the liquid. L is the length of the inlet section of the inner tube. D is the inner diameter of the inner tube. Ga=gD 3 / n L 2 ,Ja=CpL / Δiv, CpL is the specific heat at constant pressure. Δiv is latent heat. L < 5D.

4. The refrigerant distributor according to any one of claims 1 to 3, characterized in that, The refrigerant outlet is located between the adjacent heat-conducting pipes.

5. The refrigerant distributor according to any one of claims 1 to 3, characterized in that, The inner tube extends in a straight line compared to the outer tube. The structural part is an extension of the inner tube. When the inner diameter of the extended portion of the inner tube is set to D, and the length of the extended portion of the inner tube is set to L, L < 10 × D.

6. The refrigerant distributor according to any one of claims 1 to 3, characterized in that, The outer tube extends further than the inner tube. The refrigerant distributor includes a separator that separates the inner circumference of the outer tube from the outer circumference of the inner tube along the axial direction of the outer tube. The structural portion is disposed in the extended outer tube and is a confluence space within the outer tube, separated by the separator, for the refrigerant from the plurality of heat-conducting tubes to converge.

7. The refrigerant distributor according to claim 6, characterized in that, When the flow path cross-sectional area of ​​the merging space is set to A1 and the flow path cross-sectional area of ​​the inner tube is set to AS, A1 > AS.

8. The refrigerant distributor according to any one of claims 1 to 3, characterized in that, The outer tube extends further than the inner tube. The refrigerant distributor includes a separator that separates the inner circumference of the outer tube from the outer circumference of the inner tube. The structural part is an extended outer tube, and the extended outer tube has an inflow space inside the outer tube separated by the partition for the refrigerant to flow in.

9. The refrigerant distributor according to any one of claims 1 to 3, characterized in that, The inner tube extends further than the outer tube. The structure is a curved inlet pipe connected to the extended inner tube for the refrigerant to flow into.

10. The refrigerant distributor according to claim 9, characterized in that, When the inner diameter of the flow path of the curved inlet pipe is set to DR, and the length of the straight portion of the extension of the inner pipe is set to L2, L2 < 5 × DR.

11. The refrigerant distributor according to any one of claims 1 to 3, characterized in that, The flow path cross-sectional area of ​​the inner tube is defined as AS[mm]. 2 In the case of ], AS=31.6mm 2 ~201.1mm 2 。 12. A refrigerant distributor, characterized in that, have: An outer tube, in which refrigerant flows, and a plurality of heat-conducting tubes are connected at predetermined intervals to the outer tube; An inner tube, in which the refrigerant flows, is housed within an outer tube and has a refrigerant outlet for allowing the refrigerant flowing inside the inner tube to flow into the outer tube; and A structural section, disposed within the inner or outer pipe, allows the refrigerant to flow into the inner pipe. Within this structural section, the refrigerant is in a state where a gas-liquid two-phase flow has not yet developed. The refrigerant outlet is configured such that the angle θ, from the lower end of the inner tube on a vertical line passing through the center of the inner tube to the location of the refrigerant outlet, is set in the range of 10°≤θ≤80° when viewed from the center of the inner tube. In the vertical cross-section of the inner tube at the location where the refrigerant outlet hole is provided, there is only one refrigerant outlet hole. In the case where there are two refrigerant distributors, and one of the two refrigerant distributors is designated as the first refrigerant distributor and the other as the second refrigerant distributor... It has a curved inner tube that connects the inner tube of the first refrigerant distributor to the inner tube of the second refrigerant distributor. The angle θ2 of the refrigerant outlet of the second refrigerant distributor is in the range of -180° to 180°, and its absolute value is greater than the absolute value of the angle θ1 of the refrigerant outlet of the first refrigerant distributor.

13. The refrigerant distributor according to claim 12, characterized in that, The inner diameter of the end portion of the inner tube of the second refrigerant distributor on the covered side is smaller than the inner diameter of the beginning portion on the side connected to the curved inner tube.

14. A heat exchanger, characterized in that, A refrigerant distributor having any one of claims 1 to 13.

15. An air conditioning device, characterized in that, It has the heat exchanger as described in claim 14.

Images