CN101182965B - Refrigerant distributor and air conditioner with refrigerant distributor - Google Patents

Abstract

The invention relates to a refrigerant distributor for a heat exchanger. Even if the gas-liquid two-phase flow flowing into the inlet pipe is a chaotic refrigerant flow, gas-liquid separation can be reliably achieved, and refrigerant distribution of the stable gas-liquid two-phase flow can be performed in a plurality of outlet pipes. In a refrigerant distributor having an inlet pipe (42) for feeding a gas-liquid two-phase refrigerant flow (40) and a plurality of outlet pipes (43) for distributing the refrigerant flow on the downstream side of the inlet pipe, the inlet pipe has multiple The groove (44) that makes the liquid refrigerant flow on the inner surface of the tube is provided with a cylindrical refrigerant flow rectification device (61) near the entrance of the inlet pipe, and the inner space of the rectification device and the outer periphery of the rectification device and the inlet pipe The spaces between the inner faces form channels for refrigerant flow. As another specific example of the cylindrical refrigerant flow straightening device, the upstream side end is formed in a conical shape. As another specific example of the refrigerant flow rectifying device, a dense structure is formed in the central part, and a lattice shape is formed in which the outer peripheral part is sparsely structured.

Description

Refrigerant distributor and air conditioner with refrigerant distributor

technical field

The present invention relates to a refrigerant distributor for a heat exchanger used in an air conditioner such as a domestic room air conditioner, and more particularly to a refrigerant distributor for effectively functioning a heat exchanger.

Background technique

FIG. 1 is a diagram showing the configuration of a refrigeration cycle of a general household air conditioner. In Fig. 1, reference numeral 1 is a compressor, 2 is a four-way valve, 3 is a throttling device such as an electric valve, 4 is an indoor heat exchanger, and 5 is an outdoor heat exchanger. In the household air conditioner, by switching the four-way valve 2, it is possible to operate the air-conditioning equipment using the indoor heat exchanger 4 as an evaporator and the outdoor heat exchanger 5 as a condenser (solid arrow), and turn the indoor heat exchanger 5 into a condenser. The heater 4 operates as a condenser and the outdoor heat exchanger 5 operates as a heater using an evaporator (dotted arrow).

For example, during the operation of the air conditioner, the high-temperature and high-pressure refrigerant compressed by the compressor 1 flows into the outdoor heat exchanger 5 through the four-way valve 2, releases heat through heat exchange with air, and condenses. Then, after isenthalpic expansion by the throttling device 3 such as an electric valve, it becomes a gas-liquid two-phase flow mixed with gas and liquid at low temperature and low pressure, and flows into the indoor heat exchanger 4 . In the indoor heat exchanger 4, due to the heat absorption from the air, the refrigerant evaporates while increasing the dryness χ from the inlet to the outlet. Then, the refrigerant coming out of the indoor heat exchanger 4 returns to the compressor 1 to form a cycle. Incidentally, the so-called dryness χ is a value obtained by dividing the mass flow rate of refrigerant gas by the total mass flow rate of refrigerant, that is, dryness χ=mass flow rate of refrigerant gas/total mass flow rate of refrigerant.

Here, in the interior of the indoor heat exchanger 4 functioning as an evaporator, the loss of flow resistance in the piping constituting the heat exchanger greatly affects the performance degradation as an evaporator. In order to suppress this loss, it is generally configured such that a plurality of passages are branched in parallel in the indoor heat exchanger 4 to allow the refrigerant to flow. A refrigerant distributor for distributing the refrigerant of the gas-liquid two-phase flow into these multiple channels is necessary.

As a refrigerant of gas-liquid two-phase flow, since the density ratio of gas refrigerant and liquid refrigerant is tens of times, the flow velocity is very different, and the gas-liquid interface disorder causes the flow of refrigerant to be unstable. In addition, the centrifugal force caused by the bending (curved portion) of the upstream connection pipe of the refrigerant distributor and the action of gravity caused by the inclination of the inlet pipe also affect the flow imbalance of the refrigerant. Or, when the curvature of the connecting pipe upstream of the refrigerant distributor is small or when the flow direction of a two-way valve changes sharply, the subsequent flow will form a liquid film disorder, and the center of the pipe cross section where the gas phase flows will be turbulent. The flow state of a plurality of liquid droplets affects the flow imbalance of the refrigerant in the same manner as described above.

In addition, when the refrigerant flow rate varies over a wide range from a small flow rate to a large flow rate, such as in an inverter-driven indoor air conditioner in which the rotation speed of the compressor is variable, and when there is an error in the machining accuracy of the refrigerant distributor 31, it can be said that the refrigerant flows into the air conditioner. The distribution of the tube cross section of the liquid refrigerant in the distributor 31 varies greatly, or the flow of the refrigerant varies greatly.

Accordingly, passages through which evaporated liquid refrigerant sufficiently flows and passages lacking only insufficiently flowing liquid refrigerant are created in the heat exchanger. When the liquid refrigerant is short in the middle of the passage, the heat exchanger after that part cannot perform heat exchange and cannot exhibit sufficient performance. That is, the role of the refrigerant cannot be fully exerted, and it is necessary to increase the flow rate of the refrigerant to solve the insufficient part, that is, to increase the compressor speed, increase the flow rate of the refrigerant, and obtain the necessary capacity. In this way, electric energy cannot be saved due to the increase of useless work input into the compressor.

In addition, if the air that is sufficiently cooled and takes away latent heat in the channel where the liquid refrigerant flows sufficiently and the air that is hardly cooled but retains latent heat in the channel where the liquid refrigerant is deficient, if they merge downstream of the heat exchanger, the indoor fan will Condensation occurs in the wind path, and water droplets are mixed in the blown air. The dew condensation of such an indoor unit causes user's displeasure.

In the case of adopting the reheating and dehumidification method that does not lower the supply air temperature of the indoor unit, the configuration of the refrigeration cycle is as shown in Fig. 2 . That is, a throttling device 33 is provided between the refrigerant passages of the indoor heat exchanger 4, and since the refrigerant is decompressed by the throttling device 33, the parts of the passages 21 and 22 are used as condensers, and the parts of the passages 11 and 12 are used as condensers. Some are used as evaporators, and the above-mentioned reheating and dehumidification methods are realized by mixing the respective outlet temperatures. At this time, it is necessary to install the refrigerant distributor 32 in the middle of the passage of the indoor heat exchanger 4 . When the air conditioner is in operation, since the inlet of the refrigerant in the distributor 32 has a higher dryness than the distributor 32, a very small amount of liquid refrigerant must be distributed. The distribution of such high-dryness liquid refrigerant is more easily affected by the shape of the inlet pipe and gravity than the distribution of low-dryness liquid refrigerant, and thus becomes a difficult problem.

Various countermeasures have been considered for such problems related to liquid refrigerant distribution.

For example, when a refrigerant distributor is installed at the inlet of the indoor heat exchanger 4 that acts as an evaporator when the air conditioner is in operation, the refrigerant inlet dryness is relatively small at about 0.2 in general household air conditioners. In this case, as disclosed in Patent Document 1 - Japanese Patent Application Laid-Open No. 2000-105026, it has been proposed that by providing a rotating component to the refrigerant flow, a centrifugal force greater than gravity can be provided, thereby reducing gravity. effect, to achieve improved refrigerant distribution.

However, in order to provide a rotational component to the refrigerant flow, a large amount of motion is required, and the necessary amount of motion cannot be ensured when the refrigerant flow rate is small. When using the reheat dehumidification method, etc., when the refrigerant distributor is installed in the middle of the piping of the heat exchanger, since the dryness of the refrigerant is high, the amount of liquid refrigerant for imparting the swirling component is extremely small, so swirling flow cannot be generated. Therefore, as disclosed in Japanese Patent Application Laid-Open No. 2003-014337, Patent Document 2, it has been proposed to improve refrigerant distribution by reducing the influence of gravity by acting on the surface tension caused by fine grooves. .

As shown in Patent Document 1, by providing a rotational component to the refrigerant flow, although the gravitational effect caused by the inclination of the inlet pipe can be reduced to some extent, but in the case of a small refrigerant flow rate or a high degree of dryness of the inlet pipe refrigerant, etc., Still, the variation in the tube cross-sectional direction of the liquid refrigerant cannot be reduced.

On the other hand, as shown in the above-mentioned Patent Document 2, by acting on the surface tension caused by fine grooves, it is possible to reduce the influence of gravity and centrifugal force even when the flow rate of the refrigerant is small and the degree of refrigerant dryness in the inlet pipe is high. deviation of the liquid refrigerant.

However, when the bending radius of the connecting pipe located upstream of the refrigerant distributor is small or when the flow direction of the two-way valve changes sharply, the subsequent flow will form a liquid film disorder, and there will be a band in the center of the pipe section where the gas phase flows. In the flow state where there are many droplets, the effect of fine grooves cannot be obtained sufficiently. That is, in the above-mentioned case, a stable circulation is not formed in the distribution part, and the distribution ratio cannot be maintained. Furthermore, since the deviation of the liquid refrigerant varies with the magnitude of the flow rate, there arises a problem that the distribution ratio cannot be maintained in a wide flow rate range from a small flow rate to a large flow rate in the operating range.

Contents of the invention

The purpose of the present invention is to provide a refrigerant distributor, which is equipped with a refrigerant flow rectification device near the inlet of the inlet pipe with a plurality of grooves on the inner surface of the pipe and an inner pipe near the inlet of the outlet pipe, even if the flow into the inlet The gas-liquid two-phase flow of the tube is a turbulent refrigerant flow, and the gas-liquid separation can also be reliably realized and the refrigerant distribution of the gas-liquid two-phase flow can be stably performed in multiple outlet tubes.

In order to solve the above-mentioned problems, the present invention employs the following configurations.

In a refrigerant distributor having an inlet pipe for feeding a gas-liquid two-phase refrigerant flow and a plurality of outlet pipes for distributing the refrigerant flow on the downstream side of the inlet pipe, the inlet pipe has a structure on the inner surface of the pipe. A plurality of tanks for the flow of liquid refrigerant, a cylindrical refrigerant flow rectification device is provided inside the vicinity of the inlet of the inlet pipe, and the inner space of the above-mentioned rectification device and the outer peripheral part of the above-mentioned rectification device and the inner surface of the above-mentioned inlet pipe The space between forms the flow channel of the refrigerant flow.

In addition, in the above-mentioned refrigerant distributor, it is configured that the above-mentioned cylindrical refrigerant flow rectifying device is formed in a conical shape at an upstream side end, and the flow of the refrigerant is caused to collide with the conical shape so that the flow of the refrigerant Flow to the inside of the tube above the inlet tube.

In a refrigerant distributor having an inlet pipe for feeding a gas-liquid two-phase refrigerant flow and a plurality of outlet pipes for distributing the refrigerant flow on the downstream side of the inlet pipe, the inlet pipe has a structure on the inner surface of the pipe. A plurality of grooves for the flow of liquid refrigerant, a grid-shaped refrigerant flow rectification device is provided near the entrance of the inlet pipe, and the above-mentioned lattice-shaped refrigerant flow rectification device has a dense structure in the central part of the lattice, and a dense structure in the outer periphery. The density of the internal lattice forms a sparse structure.

In addition, in the above-mentioned refrigerant distributor, it is configured that an inner pipe is provided between the inlet pipe and the outlet pipe on the downstream side isolated from the refrigerant flow rectifying device, and the inner pipe has a larger diameter than the inlet pipe. The inner diameter is smaller than the outer diameter, and it is provided so as to be in contact with the inlets of the plurality of outlet pipes.

According to the present invention, even if the gas-liquid two-phase flow flowing into the inlet pipe with grooves on the inner surface of the pipe contains liquid droplets and is a turbulent flow, gas-liquid separation can be reliably achieved and gas-liquid separation can be performed stably at multiple outlet pipes. Distribution of refrigerant flow for liquid two-phase flow.

Description of drawings

FIG. 1 is a diagram showing the configuration of a refrigeration cycle of a general household air conditioner.

Fig. 2 is a diagram showing a configuration of a refrigeration cycle corresponding to reheating and dehumidification in a general household air conditioner.

Fig. 3 is a diagram showing an overall structure of a refrigerant distributor according to a first embodiment of the present invention.

Fig. 4 is a diagram showing a flow state of a refrigerant flow in a gas-liquid two-phase state flowing into a connection pipe on the upstream side of an inlet pipe in the first embodiment.

Fig. 5 is a view showing the flow state of the refrigerant flow in the vent hole (curved pipe) and the two-way valve arranged on the upstream side of the connecting pipe in the first embodiment.

Fig. 6 is a diagram schematically showing the state of refrigerant flow due to the provision of rectifying means near the inlet pipe of the first embodiment.

Fig. 7 is a diagram showing refrigerant piping using the refrigerant distributor of the first embodiment in the refrigerant circuit of the indoor heat exchanger of the household air conditioner.

Fig. 8 is a diagram showing another configuration of the rectification device of the refrigerant distributor according to the second embodiment of the present invention.

Fig. 9 is a diagram showing another configuration of the rectification device of the refrigerant distributor according to the third embodiment of the present invention.

Detailed ways

Hereinafter, the refrigerant distributors according to the first, second and third embodiments of the present invention will be described in detail with reference to the drawings.

first embodiment

Hereinafter, a refrigerant distributor according to a first embodiment of the present invention will be described in detail with reference to FIGS. 3 to 7 . Fig. 3 is a general configuration diagram showing a refrigerant distributor according to a first embodiment of the present invention. In Fig. 3, reference numeral 40 is a refrigerant flow, 41 is a connecting pipe, 42 is an inlet pipe, 43 is an outlet pipe, 44 is a tank, 45 is an inner pipe, 46 is a flange, and 46a is a distribution of separated liquid. Flow channel, 46b is the distribution flow channel of the separated liquid, 47 is a cross-sectional view of the flange, 60 is a cross-sectional view of the setting position of the rectification device 61, 61 is the rectification device of the first embodiment, and 62 is the rectification device. fixed mechanism.

In Fig. 3, the refrigerant distributor of the first embodiment of the present invention has a connecting pipe 41, an inlet pipe 42, and a plurality of outlet pipes 43 through which the refrigerant flow 40 in the gas-liquid two-phase state flows in, and the connecting pipe 41 and the inlet An annular straightening device 61 is provided between the pipes 42 , and a plurality of fine spiral grooves 44 are provided on the inner surface of the inlet pipe 42 .

Reference numeral 60 is a diagram cut along the A-A section where the rectifying device 61 is installed. The rectification device 61 is fixed on the pipe section center of the inlet pipe 42 with the rectification device 61 fixing mechanism. At this time, the outer diameter of the straightening device 61 is smaller than the minimum inner diameter of the inlet pipe 42 so that the liquid film flows between the inner periphery of the connecting pipe 41 and the outer periphery of the straightening device 61 . In this embodiment, for example, as shown in FIG. 3 , a plurality of protrusions 62 are provided on a part of the outer circumference of the straightening device 61 and fixed between the top of the spiral groove and the outer circumference of the straightening device 61 .

By providing an inner tube 45 having an outer diameter smaller than the smallest inner diameter of the inlet tube 42 at the outlet of the inlet tube 42, a double-layered tube part X (consisting of the outlet of the inlet tube 42 and the inner tube 45) is formed. Reference numeral 46 is a flange for fixing the inner pipe 45, and 47 is a diagram of cutting the flange along the B-B section.

Fig. 4 is a diagram showing a flow state of a refrigerant flow in a gas-liquid two-phase state flowing into a connection pipe on the upstream side of an inlet pipe in the present embodiment. Fig. 5 is a view showing the flow state of the refrigerant in the vent hole (curved pipe) and the two-way valve arranged on the upstream side of the connecting pipe in the present embodiment.

When the refrigerant distributor of this embodiment is used, for example, in an air conditioner, if the upstream side of the connecting pipe 41 is a long enough straight pipe, the flow state of the refrigerant flow 40 in the gas-liquid two-phase state flowing into the connecting pipe 41 It is as shown in Figure 4(a). That is, it is an annular flow (annular flow) in which the liquid phase flows in the form of a film on the inner wall of the tube and the gas phase flows in the center of the tube cross section. However, in fact, as shown in Figure 5, in the upstream of the connecting pipe 41, there are many cases where a vent hole (curved pipe) and a two-way valve are arranged, and this situation becomes the cooling of the connecting pipe 41 shown in Figure 4 (b). The flow state of the agent flow.

Figure 5(a) is the state inside the vent pipe, and Figure 5(b) is the state inside the two-way valve. The valve body is omitted in Fig. 5(b). Figure 5 shows the flow from a horizontal direction to a vertical downward flow. As shown in Fig. 5, the refrigerant after passing through the vent hole and the two-way valve, etc., is in a flow state in which the liquid film is disordered and there are many liquid droplets in the center of the tube cross section where the gas phase flows due to the sudden change of the flow direction. If it flows into the inlet pipe in such a flow state, the gas-liquid separation cannot be completely performed only in the spiral groove portion 44, resulting in a decrease in separation efficiency and a fluctuation in the distribution ratio.

Fig. 6 is a diagram schematically showing the state of refrigerant flow due to the provision of rectifying means near the inlet pipe of the first embodiment. In FIG. 6, when the refrigerant flow 40 in the gas-liquid two-phase state flows into the inlet pipe 42 through the rectification device 61, as shown in FIG. the upper end of. Due to this collision, the liquid droplets in the direction of the outer circumference of the tube adhere directly to the liquid film flowing through the inner wall of the inlet tube 42 . In addition, the liquid droplets directed toward the center of the tube cross-section merge with the flow at the center of the tube cross-section. Moreover, since the pipe cross section becomes a flow channel that shrinks from the connecting pipe 41 at the rectifying device 61 (the inner diameter of the rectifying device is smaller than the inner diameter of the connecting pipe 41), and then expands at the inlet pipe 42, the flow at the center of the pipe cross section becomes rectified. A flow that expands when flowing into the inlet pipe 42 after contracting inside the device 61 (see the arrow shown in FIG. 6 ). The liquid droplets following this flow adhere to the liquid film flowing through the inner wall of the inlet pipe 42 . Therefore, the refrigerant flowing into the inlet pipe 42 becomes a stable annular flow.

In the rectifying device 61 of this embodiment, the thicker the tube wall, the more the amount of droplets adhered to the liquid film, but the flow loss increases due to flow resistance. Therefore, it is necessary to determine the optimum size of the straightening device 61 according to the dryness of the inlet and the pipe shape to the connecting pipe 41 in this embodiment. For example, since there is less liquid phase in the tube section, the higher the inlet dryness, the thinner the liquid film and the smaller the droplet volume. That is, the higher the inlet dryness of this embodiment, the thinner the tube wall can be without greatly increasing the flow loss caused by the rectifying device, and the liquid droplets are attached, and the refrigerant flowing into the inlet tube 42 becomes stable. Annulus (circular flow).

In addition, the distance between the rectification device 61 and the double pipe part X needs to be optimally arranged according to the flow rate range so that the droplet adhesion on the downstream side of the rectification device 61 is sufficiently advanced. That is, the distance between the rectifying device 61 and the double pipe section X needs to be greater than or equal to the range where the liquid droplets passing through the rectifying device adhere to the liquid film. The higher the flow rate, the faster the flow velocity of the gas phase at the center of the tube section, and the faster the flow velocity of the corresponding liquid droplets, the wider the attachment range to the liquid film after passing through the rectification device, so it is necessary to lengthen the rectification device 61 to the double-layer pipe The distance of part X.

As described above, when the refrigerant flow 40 passing through the rectifying device 61 flows in the inlet pipe 42, the liquid refrigerant is drawn into the groove due to the surface tension of the fine spiral groove 44 provided on the inner surface. Here, since the liquid refrigerant is more likely to be affected by surface tension as the interval between the grooves is narrower, finer grooves are preferable. In addition, in Fig. 3, the total cross-sectional area of the groove portion in the circumferential direction indicated by the oblique line in the A-A section must be larger than the volume flow rate of the liquid refrigerant per unit time and per unit cross-sectional area. When the cross-sectional area of the groove is smaller than the volume flow rate of the liquid refrigerant, the liquid refrigerant overflows from the groove, and the effect of the groove becomes small.

In the refrigerant flow 40, since the liquid refrigerant is introduced into the groove of the outer peripheral part (the inner wall of the inlet pipe 42), the gas refrigerant flows in the center part of the pipe section of the inlet pipe 42, and becomes an annular shape in which the liquid refrigerant flows through the groove 44. flow.

The refrigerant flow 40 that has reached the outlet portion of the inlet pipe 42 flows in the double pipe portion X having the inner pipe 45 . At this time, the gas refrigerant in the central portion of the refrigerant flow 40 flows toward the inner side X1 of the inner pipe 45, and the liquid refrigerant in the outer peripheral portion flows into the space X2 sandwiched between the groove portion 44 and the outer periphery of the inner pipe 45, and the gas and liquid are roughly separated ( Refer to Figure 3). This is because the liquid refrigerant is held in the groove portion 44 due to the surface tension in the groove portion 44 . Therefore, the surface tension can be used to reduce the influence of the inclination of the inlet pipe 42 in the direction of gravity (when the inlet pipe 42 is not vertically arranged).

When the pressure loss of the liquid refrigerant acting on the outer peripheral portion X2 of the inner tube 45 is greater than the pressure loss of the gas refrigerant acting on the inner X1 of the inner tube 45, the refrigerant accumulates in the space X2, and the refrigerant liquid sometimes flows from The gap X2 in the outer peripheral portion of the inner tube 45 overflows. If this is done, the overflowed liquid refrigerant enters the inside X1 of the inner pipe 45, and the separation of the liquid refrigerant and the gas refrigerant cannot be performed well. On the contrary, the pressure loss on the liquid refrigerant acting on the outer peripheral portion X2 of the inner tube 45 is smaller than the pressure loss on the gas refrigerant acting on the inner X1 of the inner tube 45, the gas refrigerant enters the space X2 portion, and the liquid refrigerant Separation from gaseous refrigerant does not work well.

Therefore, in order to reliably guide the liquid refrigerant flowing in the spiral groove 44 to the gap X2 in the outer periphery, the outer diameter of the inner pipe 45 is a diameter whose radius is from the center of the inlet pipe to the top of the groove. In addition, the length of the inner tube 45 is a length until the difference in pressure loss at the junction of the gas refrigerant flowing through the interior X1 and the liquid refrigerant flowing through the gap X2 in the outer peripheral portion becomes zero. In this way, the inner pipe 45 is provided on the inlet side of the outlet pipe 43, and has the function of sending the flow of the refrigerant separated from the liquid refrigerant and the gas refrigerant by the rectifier 61 to the respective outlet pipes in that state. . In other words, if there is no inner pipe, the liquid refrigerant and the gas refrigerant can collide at the inlet side of the outlet pipe and become mixed again, and the situation that the gas-liquid ratio is not distributed to the respective outlet pipes can occur. .

The structure of the present embodiment shown in FIG. 3, especially the structure of the channel hole using the flange 46, can properly distribute the liquid and the gas since they are separated and distributed. The distribution ratio can be controlled only by the distribution of the liquid refrigerant, and the gas refrigerant is automatically distributed by the pressure loss of the flow channel after the gas-liquid merge. Without changing the distribution ratio, the respective total areas of the distributed channels can be changed.

In FIG. 3, the holes 46a, 46b are made to be the same as each other. The refrigerant flow 40 passing through the double pipe portion X having the inner pipe 45 is evenly distributed to the outlet pipe 43 through the holes 46 a and 46 b penetrating the flange 46 . In addition, the gas refrigerant is distributed to the respective outlet pipes from the large hole in the central portion shown in the sectional view 47 of the flange 46 shown in FIG. 3 . In this embodiment, although the holes through the flange are used to distribute the liquid refrigerant, it is also possible to use different pipes that change the diameter and length of the pipe to determine the flow resistance to form the flow path of the liquid refrigerant.

Fig. 7 is a refrigerant piping diagram showing the refrigerant distributor of the first embodiment employed in the refrigerant circuit of the indoor heat exchanger of the household air conditioner. Next, the structure and operation of the indoor heat exchanger of the household air conditioner using the refrigerant distributor of this embodiment will be described with reference to FIG. 7 . In FIG. 7 , refrigerant distributors 31 and 32 of this embodiment are installed in the middle of the refrigerant piping.

Indoor Heat Exchanger The heat exchangers 200 , 201 , and 202 arranged in a curved manner are arranged in the casing 114 in order to exchange heat between air and refrigerant. Refrigerant distribution pipes 31 and 32 are respectively provided in the heat exchangers 201 and 202 . Reference numeral 112 is a dehumidification valve for reheating and dehumidification, and 113 is a DC fan for supplying air volume for heat exchange. In the heat exchangers 200 , 201 , and 202 , a plurality of fins are stacked in a vertical direction on the paper, and a plurality of heat transfer tubes pass through the fins. Furthermore, a plurality of heat transfer tubes are connected by, for example, a U-shaped connecting tube to form a refrigerant passage.

The refrigerant distributor 31 is a distributor that distributes one channel to two channels, and the refrigerant channel 310 is divided into two channels of the refrigerant channels 311 and 312 by the refrigerant distributor 31 . The refrigerant passages 311 and 312 pass through the heat exchangers 200 and 201 and then merge into one passage, which is connected with the refrigerant passage 320 provided with the dehumidification valve 112 to form a continuous refrigerant circuit.

In addition, the refrigerant distributor 32 is also a distributor that distributes one channel to two channels like the refrigerant distributor 31 , and the refrigerant channel 320 is divided into two channels of the refrigerant channels 321 and 322 . The refrigerant passages 321 and 322 merge into one passage after passing through the heat exchanger 202, and connect to the refrigerant passage 323 to form a continuous refrigerant circuit. Then, the refrigerant passage 323 leads to an unshown outdoor unit, passes through a compressor, an outdoor heat exchanger, and a decompression device, and returns to FIG. 7 as a refrigerant passage 310 .

Next, the operation of the indoor heat exchanger will be described. During operation of the air conditioner, refrigerant flows into the refrigerant passage 310 from an outdoor unit (not shown). (direction of the solid arrow). The inflowing refrigerant is distributed to two passages of the refrigerant passages 311 and 312 by the refrigerant distributor 31 , and exchanges heat with the air by the heat exchangers 200 and 201 . Then the refrigerant passages 320 merge into one passage, and flow into the refrigerant distributor 32 after passing through the dehumidification valve 112 . Then, the two passages redistributed as refrigerant passages 321 and 322 exchange heat with air in the heat exchanger 202 .

When the refrigerant distributor 32 shown in FIG. 2 uses the refrigerant distributor of this embodiment, the gas-liquid two-phase refrigerant passing through the refrigerant channel 320 with a high degree of dryness (about χ=0.7) passes through the connecting pipe 41, the rectifier The device 61 and the groove portion 44 of the inlet pipe 42 form an annular flow, and gas-liquid separation is performed in the double pipe portion X ( X1 , X2 ) constituted by the inner pipe 45 . Then, the two channels evenly distributed to 321 and 322 exchange heat with air in the heat exchanger 202 .

At this time, the connecting pipe 41 connecting the dehumidification valve 112 and the refrigerant distributor 32 is short, and the liquid film is disordered. Even in the state where the liquid droplets flow through the center of the section, the rectification device 61 causes the liquid droplets to adhere to the liquid film. Therefore, the influence caused by the turbulence of the refrigerant flow is reduced, and a stable annular flow flows into the inlet pipe 42 . Next, the refrigerant flow flowing into the inlet pipe 42 separates the liquid refrigerant and the gas refrigerant mainly due to the effect of surface tension in the space X2 on the side of the groove portion 44 and the inner side X1 of the inner pipe 45, so that the inlet can be reduced. The inclination of the direction of gravity of the pipe 42 and the influence of the centrifugal force of the bend (curved portion) of the connecting pipe.

Therefore, even if the refrigerant flow upstream of the inlet pipe with fine grooves is in a chaotic flow state in which liquid droplets scatter on the gas phase side of the annular flow, it can be optimally distributed over a wide range of flow rates. than to distribute the refrigerant. Furthermore, there is no need to run the compressor more than necessary, reducing electrical energy input. Furthermore, problems such as dew condensation on the indoor units due to deterioration of the distribution ratio can be eliminated.

In the above description, as the present embodiment, the operation of the distributor that divides one channel into two channels has been described, but the same effect can be obtained even when the outlet pipe is three channels, four channels, or multiple channels. . In addition, in this embodiment, the case where the refrigerant distributor is used in the middle of the refrigerant piping of the indoor heat exchanger has been described, but it is also applicable to the case where reheating and dehumidification are not performed, for example. In this case, since there is no need for a dehumidification valve, as in the case where there are two passages from the inlet to the outlet of the indoor heat exchanger, even when the dryness of the refrigerant at the inlet is low (when the humidity is high), it can be dehumidified. The same effect can be obtained by optimizing the outer diameter, wall thickness, and length of the straightening device 61, the shape and inner diameter of the groove portion 44 of the inlet pipe 42, and the outer diameter and wall thickness of the inner pipe 45 according to the state of the inlet refrigerant.

second embodiment

Hereinafter, a rectification device of a refrigerant distributor according to a second embodiment of the present invention will be described with reference to FIG. 8 .

Fig. 8 is a diagram showing the structure of another rectification device of the refrigerant distributor according to the second embodiment of the present invention.

The rectifying device 71 shown in FIG. 8 is installed at the center of the tube section between the connection tube 41 and the inlet tube 42 through which the gas-liquid two-phase refrigerant flow 40 flows (the same arrangement as that shown in FIG. 3 ). The configurations of the connection pipe 41, the inlet pipe 42, and the downstream side of the inlet pipe 42 are the same as those of the first embodiment. In addition, the gas-liquid separation effect and the effect when it is installed in a heat exchanger are also the same as those of the first embodiment.

The flow upstream side end portion of the rectification device 71 shown in FIG. 8 is conical toward the flow upstream side from the outer periphery of the pipe toward the center of the cross-section of the pipe. When the gas-liquid two-phase refrigerant flow 40 reaches the rectifying device 71 from the connecting pipe 41, it collides with the upstream end of the rectifying device 71 and adheres to the liquid film flowing through the inner wall of the inlet pipe 41 toward the outer circumference of the pipe.

In addition, since the cross-section of the pipe is made into a flow path that narrows at the straightening device 71 from the connecting pipe 41 and expands at the inlet pipe 42, the flow at the center of the pipe cross-section becomes when it flows into the inlet pipe 41 after shrinking inside the straightening device 71. Expanded flow. The liquid droplets following this flow adhere to the liquid droplets flowing through the inner wall of the inlet pipe 41 (grooves are formed on the inner surface of the inlet pipe 42 as in the first embodiment). Therefore, the refrigerant flowing into the inlet pipe 42 becomes a stable annular flow.

In the straightening device 71 of this embodiment, the thicker the pipe wall, the more the amount of droplets attached, but the flow loss caused by the straightening device will increase due to flow resistance. Therefore, it is necessary to determine the optimum size of the straightening device 71 according to the dryness of the inlet to be used and the pipe shape to the connecting pipe 41 . For example, as in the first embodiment, the higher the inlet dryness is, the less liquid phase exists in the tube section, so the thickness of the liquid film is thinner, and the droplet volume is smaller. That is, when the inlet dryness is higher in this embodiment, the thickness of the tube wall can be reduced without greatly increasing the loss caused by the rectifying device, and the liquid droplets adhere, and the refrigerant flowing into the inlet tube 42 becomes a stable ring. State flow.

In addition, depending on the flow rate range, it is necessary to optimally arrange the distance between the rectifying device 71 and the double-layered pipe part X so that the droplet attachment downstream of the rectifying device 71 is sufficiently performed. That is, the distance between the rectifying device 71 and the double pipe part X must be greater than or equal to the range in which the liquid droplets after passing through the rectifying device adhere to the liquid film. The larger the flow rate, the faster the flow velocity of the gas phase at the center of the tube section, and the faster the corresponding droplet velocity, the wider the range of adhesion to the liquid film after passing through the rectifying device. Therefore, it is necessary to make the rectifying device 71 and the double layer The distance of the pipe part X is lengthened.

By configuring the straightening device 71 as described above, in addition to the advantages of the first embodiment, even if the tube wall is thick, the flow of the gas phase at the center of the tube section will not be too disturbed by the provision of the conical portion, and a part of the liquid droplets can be separated. Guided to the outer peripheral side, the loss caused by the straightening device is reduced, and even if the refrigerant flow upstream of the inlet pipe is in a chaotic flow state such as liquid droplets flying on the gas phase side of the annular flow, it can be optimized in a wide range. The distribution ratio of the refrigerant is distributed.

third embodiment

Next, a rectification device of a refrigerant distributor according to a third embodiment of the present invention will be described with reference to FIG. 9 . Fig. 9 is another configuration diagram showing a rectification device of a refrigerant distributor according to a third embodiment of the present invention.

The rectification device 81 shown in FIG. 9 is provided on the pipe section between the connection pipe 41 and the inlet pipe 42 into which the gas-liquid two-phase refrigerant flow 40 flows. The configurations of the connection pipe 41, the inlet pipe 42, and the downstream side of the inlet pipe 42 are the same as those of the first embodiment. Moreover, the effect of its gas-liquid separation and the effect when it is installed in a heat exchanger are also the same as those of the first embodiment.

The rectifying device of the third embodiment is different from the cylindrical body structure shown in FIG. 3 , and is constituted by a grid-shaped structure that extends over the entire cross-section near the entrance of the inlet pipe 42 with spiral grooves on the inner surface of the pipe. The density is formed so that the opening ratio of the central part of the tube is smaller than the opening ratio of the outer peripheral part of the tube. That is, it is denser at the center and sparser at the outer periphery. With the structure of such rectifying device, in the central part of the lattice structure, due to its dense lattice shape, the flow velocity of the gas refrigerant flow containing liquid droplets is slower than that of the outer peripheral part, and the liquid droplets colliding with the lattice in the central part are eliminated. Pulled to the outer peripheral part with a fast flow rate, and then attached to the liquid droplets flowing through the spiral groove on the inner surface of the inlet pipe. Therefore, the refrigerant flowing into the inlet pipe 42 becomes a stable annular flow.

The smaller the grid interval of the flow rectification device 81 is, the larger the thickness of the grid is, and the larger the droplet adhesion amount is at a high flow rate, but the loss caused by the flow rectification device increases. Therefore, it is necessary to determine the density and thickness of the grid according to the inlet dryness and flow range used. In addition, it is necessary to select the distance between the straightening device 81 and the double pipe part X according to the flow rate range used so that the droplet adhesion downstream of the straightening device 81 is sufficiently performed.

For example, as in the first embodiment, the higher the inlet dryness, the less liquid phase exists in the tube section, so the thickness of the liquid film is thin and the amount of droplets is small. That is, the higher the inlet dryness when adopting this embodiment, the more sparse the density of the grid can be made without greatly increasing the loss caused by the rectifying device, the liquid droplets adhere, and the refrigerant flowing into the inlet pipe 42 becomes stable. circular flow.

In addition, the distance between the rectifying device 81 and the double-layer pipe part X needs to be optimally arranged according to the flow rate range so that the droplet adhesion downstream of the rectifying device 81 can be sufficiently performed. That is, the distance between the rectifying device 81 and the double pipe portion X must be set to be greater than or equal to the range where the liquid droplets passing through the rectifying device adhere to the liquid film. The higher the flow rate, the faster the flow velocity of the gas phase at the center of the cross-section of the tube, and the faster the flow velocity of the corresponding liquid droplets. Since the range of adhesion to the liquid film after passing through the rectification device becomes wider, it is necessary to lengthen the rectification device 81 and reach the double layer. The distance of the tube X.

By constituting the rectifying device 81 as shown in FIG. 9, in addition to the advantages of the first embodiment, it has a simpler structure even if the refrigerant flow upstream of the inlet pipe is mixed such that liquid droplets are scattered on the gas phase side of the annular flow. In the flow state, the refrigerant can be distributed with the best distribution ratio in a wide flow range.

As shown in FIG. 9, by providing a dense and dense grid-like rectification device near the inlet of the inlet pipe, even in the case of a chaotic refrigerant flow of gas-liquid two-phase flow including liquid droplets, the first and second In the second embodiment, even if the refrigerant flow upstream of the inlet pipe with fine grooves is in a chaotic flow state such that liquid droplets are scattered on the gas phase side of the annular flow, refrigeration can be performed with an optimal distribution ratio in a wide flow range. Dosage distribution.

As described above, the refrigerant distributor of the embodiment of the present invention is characterized in that it has the following structure, and exerts corresponding functions and effects. That is, in a refrigerant distributor having an inlet pipe and a plurality of outlet pipes branched from the inlet pipe, and having a plurality of fine grooves on the inner surface of the inlet pipe, it is characterized in that between the inlet pipe and the outlet pipe , in such a way that a plurality of outlet pipe inlets are connected on the outlet side of the inlet pipe, a double-layered pipe part area with an inner pipe having an outer diameter smaller than the minimum inner diameter of the inlet pipe is provided, and an inlet formed near the inlet of the inlet pipe is provided A cylindrical (annular) straightening device with a flow channel near the inner wall and the center of the pipe, or a cylindrical (annular) rectifying device that is conical from the outer circumference of the pipe to the center of the cross-section of the pipe at the upstream end of the flow, Or a grid-like rectification device formed densely and densely.

Since the refrigerant distributor of this embodiment has the characteristics as described above, even if the gas-liquid two-phase flow is a chaotic flow, the liquid droplets will adhere to the liquid film due to the rectification device of the refrigerant flow formed near the inlet of the inlet pipe. to become a stable annular flow. In addition, the inner surface groove of the grooved pipe is used to maintain the gas-liquid two-phase flow forming annular fluidization, so that the liquid refrigerant in the groove portion flows on the outer peripheral side with the double-layer pipe portion, and the gas refrigerant flowing through the center is Inner peripheral flow.

In this way, even if the refrigerant flow upstream of the inlet pipe is in a chaotic flow state in which droplets are scattered on the gas phase side of the annular flow, not only in the high flow rate and low dryness region dominated by the swirling component formed by the grooved pipe, Moreover, in the region where the low flow rate and high dryness of the rotating component formed by the grooved tube do not occur, the deviation of the liquid refrigerant caused by the centrifugal force of the bend (bend portion) of the connecting pipe upstream of the inlet pipe and the loss of gravity can also be reduced. Affected, the refrigerant can be distributed with the best distribution ratio in a wide flow range. Furthermore, it is not necessary to operate the compressor more than necessary, and the input of electric energy can be reduced. Furthermore, it is possible to eliminate problems such as dew condensation on the indoor unit due to deterioration of the distribution ratio. In addition, by using the function of separating gas and liquid, by using the refrigerant distributor of this embodiment in the air conditioner, if the refrigerant distributor is used, only the liquid refrigerant is recovered and introduced into the indoor heat exchanger, so that the gas refrigerant does not Returning to the compressor through the indoor heat exchanger ensures reliability (since no excess liquid is mixed in the compressor) and operates the air conditioner at high efficiency.

Claims (5)

1. A refrigerant distributor having an inlet pipe for sending into a gas-liquid two-phase refrigerant flow and a plurality of outlet pipes for distributing the above-mentioned refrigerant flow on the downstream side of the inlet pipe, characterized in that, The above-mentioned inlet pipe has a plurality of grooves on the inner surface of the pipe for the liquid refrigerant to flow, A cylindrical refrigerant flow straightening device is provided inside near the inlet of the inlet pipe, The inner space of the flow rectification device and the space between the outer peripheral portion of the flow rectification device and the inner surface of the inlet pipe form a refrigerant flow path. 2. The refrigerant distributor according to claim 1, wherein: The above-mentioned cylindrical refrigerant flow rectification device is formed in a conical shape toward the upstream side of the flow and from the outer periphery of the tube toward the center of the cross-section of the tube at the upstream side end, By causing the refrigerant flow to collide with the conical shape, the flow direction of the refrigerant flow is directed toward the pipe inner surface of the inlet pipe. 3. A refrigerant distributor having an inlet pipe for sending into a gas-liquid two-phase refrigerant flow and a plurality of outlet pipes for distributing the above-mentioned refrigerant flow on the downstream side of the inlet pipe, characterized in that, The above-mentioned inlet pipe has a plurality of grooves on the inner surface of the pipe for the liquid refrigerant to flow, A grid-shaped refrigerant flow rectification device is arranged near the entrance of the above-mentioned inlet pipe, The grid-shaped refrigerant flow rectifying device has a dense structure with dense grids in the central part, and a sparse grid with dense grids in the outer peripheral part. 4. The refrigerant distributor according to claim 1, 2 or 3, characterized in that, On the downstream side isolated from the above-mentioned refrigerant flow straightening device, an inner pipe is provided between the above-mentioned inlet pipe and the above-mentioned outlet pipe, The inner pipe has an outer diameter smaller than the inner diameter of the inlet pipe, and is provided in contact with inlets of the plurality of outlet pipes. 5. An air conditioner, characterized in that, The refrigerant distributor described in claim 1, 2, 3 or 4 is used in the refrigerant path of the indoor heat exchanger.

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