JPH11166795A - Heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure more efficient heat exchange by eliminating deviation of void rate among a plurality of channels provided for the heating tubes constituting a heat exchanger and making uniform the flow rate of refrigerant for respective channels thereby making uniform the pressure loss of refrigerant flowing through the heating tubes. SOLUTION: Temperature increases as the air flows through a heat exchanger having heating tubes 21. Temperature of refrigerant flowing through a channel 21a is constant at, all times and the temperature difference between the refrigerant and the air is large on time air flow-in side and the state is reversed on the flow-out side. Since the heating tube 21 has a larger quantity of exchanging heat on the air flow-in side, refrigerant begin to be condensed quicker and the liquid phase s strengthened for the refrigerant lowing on the air flow-in side whereas gas phase is strengthened on the air flow-out side. The strong liquid phase and gas phase are fed together into a mixing chamber 22 and mixed and then arranged into substantrally uniform state before being distributed to respective channels 21a. According to the arrangement, difference of void rate between the flow-in side and the flow-out side is decreased thus decreasing pressure loss among respective channels 21a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger constituting an air conditioner such as a car air conditioner.

[0002]

2. Description of the Related Art Among heat exchangers constituting an air conditioner such as a car air conditioner, a condenser performs a heat exchange between a high-temperature and high-pressure gas refrigerant sent from a compressor and air, thereby performing a gas refrigerant. Is cooled and condensed and liquefied.

FIG. 7 shows an example of a capacitor. The condenser has a core portion 3 formed by alternately stacking heat transfer tubes 1 and radiation fins 2, an inlet pipe 4 and an outlet pipe 5 for gas refrigerant, and is provided on one side of the core portion 3. And a header 7 provided on the other side of the core portion 3 to guide the flow of the gas refrigerant in the opposite direction.

[0004] A partition plate 8 is provided inside the header 6, and the gas refrigerant flowing into the header 6 from the inlet pipe 4 in the condenser passes through the heat transfer tube 1 located above the partition plate 8 in the header 7. , And exchange heat with the air flowing between the radiation fins 2 in the core portion 3. Then, after flowing into the header 7 and turning, the heat flows through the heat transfer tube 1 located below the partition plate 8 toward the header 6, and heat exchange is performed again in the core portion 3. The gas refrigerant exchanges heat with air in the course of flowing through the core portion 3 to become a liquid refrigerant, flows into the header 6, and flows out of the outlet pipe 5.

FIG. 8 shows a plan cross section of the capacitor. A plurality of flow paths 1 a are provided inside the heat transfer tube 1 along the length direction of the heat transfer tube 1. Each flow path 1a is individually formed independently so that the refrigerant flowing in the adjacent flow path does not mix.

FIG. 9 is a graph showing the air temperature with respect to the distance in the air flow direction (width direction of the heat transfer tube) in the heat transfer tube 1. According to this graph, it can be seen that the temperature of the air rises as the air proceeds from the inflow surface to the outflow surface in the flow direction of the air. However, the temperature of the refrigerant flowing through the flow path 1a is always constant (saturation temperature). The temperature difference between the refrigerant and the air is large on the inflow surface side of the air, and the temperature difference is small on the outflow surface side. As a result, in the heat transfer tube 1, the amount of exchange heat is larger on the inflow surface side of the air than on the outflow surface side, and the refrigerant starts to condense earlier, and the refrigerant flowing through the flow path 1a on the inflow surface side of the air has a liquid phase. A phenomenon occurs in which the refrigerant flowing through the flow path 1a on the outflow surface side becomes strong (liquid rich) and the gas phase becomes strong (gas rich).

It has been found that this phenomenon occurs not only in the condenser but also in the evaporator which is a heat exchanger having a similar configuration. The evaporator evaporates the liquid refrigerant which has been liquefied by the condenser and has become a low-temperature and low-pressure state in the process of passing through the expansion valve, thereby removing heat from the air flowing outside and cooling it.

FIG. 10 shows an example of an evaporator. The evaporator includes a core portion 13 formed by alternately stacking heat transfer tubes 11 and radiation fins 12, a gas refrigerant inlet-side header 14 provided above the core portion 13, and a core portion 1.
3 is provided with a gas refrigerant outlet header 15 provided above the core 3, a lower header 16 provided below the core 13 to guide the flow of the gas refrigerant in the opposite direction, and the like.

In this evaporator, the liquid refrigerant flowing into the inlet header 14 flows through the heat transfer tube 11 located below the inlet header 14 toward the lower header 16, and flows between the radiation fins 12 in the core 13. The refrigerant exchanges heat with the flowing air to become a gas-liquid two-phase refrigerant. After flowing into the lower header 16 and turning, the outlet header 15
Flows through the heat transfer tube 1 located below the heat transfer tube 1 toward the outlet header 15, performs heat exchange again in the core 13, turns into a gas refrigerant, and flows out of the outlet header 15.

FIG. 11 shows a vertical section of the evaporator. Inside the heat transfer tube 11, a plurality of flow paths 11a are provided similarly to the heat transfer tube 1 of the condenser. Each flow path is individually formed independently so that the refrigerant flowing in the adjacent flow path does not mix.

FIG. 12 is a graph showing the air temperature with respect to the distance in the air flow direction (width direction of the heat transfer tube) in the heat transfer tube 1. According to this graph, it can be seen that the temperature of the air decreases as the air proceeds from the inflow surface to the outflow surface in the flow direction of the air, but the temperature of the refrigerant flowing through the flow path 11a is always constant (saturation temperature). Therefore, the temperature difference between the refrigerant and the air is large on the air inflow surface side, and the temperature difference is small on the outflow surface side. As a result, in the heat transfer tube 1, the amount of exchange heat is larger on the inflow surface side of the air than on the outflow surface side, and the refrigerant starts to condense earlier, and the refrigerant flowing through the flow path 11a on the air inflow surface side has a gas phase. A strong (gas-rich) refrigerant flowing through the flow path 11a on the outflow surface side has a strong liquid phase (liquid-rich) phenomenon.

[0012]

As described above, in a conventional heat exchanger such as a condenser or an evaporator,
There is a problem that the pressure loss of the refrigerant flowing through the flow path provided in the heat transfer tube is not uniform, and the flow rate of the refrigerant in each flow path is not uniform, so that effective heat exchange cannot be obtained.

The present invention has been made in view of the above circumstances, and eliminates a bias in the void ratio of a plurality of flow paths provided in a heat transfer tube constituting a heat exchanger, and reduces the flow rate of refrigerant flowing through each flow path. The purpose is to make the heat exchanger uniform and improve the performance.

[0014]

As means for solving the above-mentioned problems, a heat exchanger constructed as follows is employed. This heat exchanger has a heat transfer tube in which a plurality of flow paths are provided along the length direction, an inflow port connected to one end of the heat transfer tube to serve as a fluid inlet, and a heat transfer tube at the other end. A heat exchanger comprising: an outlet that is connected as a fluid outlet; and a fin that is provided in contact with the outer surface of the heat transfer tube to increase the heat exchange efficiency between the fluid and gas flowing outside the heat transfer tube. In the heat transfer tube, a mixing chamber is provided in which the plurality of flow paths are opened at the same time and the fluid is mixed.

In this heat exchanger, the fluid flowing through each flow path is mixed by flowing into the mixing chamber, and then is distributed again to each flow path. Since the fluids are mixed in the mixing chamber, for example, even if the states of the fluids flowing in the respective flow paths are different from each other, the fluids are mixed in the mixing chamber, so that a uniform state is provided.

In this heat exchanger, the heat transfer tube is formed by a pair of plate-like halves each having a plurality of grooves formed on one side surface along a length direction and having a recess where the grooves merge together. Body
The above-mentioned one side is bonded together, the channel is provided by overlapping grooves, and the mixing chamber is provided by overlapping recesses.

In this heat exchanger, a heat transfer tube having a plurality of flow paths and a mixing chamber is formed by bonding a pair of plate-shaped halves.

In this heat exchanger, the heat transfer tube is provided such that a pair of plate bodies whose both side edges along a length direction are bent toward one side face each other, and the heat transfer tubes are arranged in a longitudinal direction of the plate body. A plurality of corrugated plates that are bent in a wave shape so as to provide a groove are sandwiched between a pair of plate members in a state where they are separated from each other in the longitudinal direction of the plate member, and are configured by laminating the grooves of the plate member and the corrugated plate. And the mixing chamber is provided between the corrugated plates.

In this heat exchanger, a heat transfer tube having a plurality of flow paths and a mixing chamber is formed by bonding a plurality of corrugated plates between a pair of plate members.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a heat exchanger according to the present invention will be described with reference to FIGS. The condenser constituting the car air conditioner has a core portion formed by alternately laminating heat transfer tubes and radiation fins, a refrigerant inlet pipe and an outlet pipe, and one side portion of the core portion as in the conventional case. And a header provided on the other side of the core to guide the flow of the gas refrigerant in the reverse direction.

FIG. 1 shows a heat transfer tube 21 constituting a core portion. The heat transfer tube 21 has the appearance of a flat tube having a uniform width and thickness, but a plurality of flow passages 21a through which a refrigerant (fluid) flows are provided along the length thereof. At a substantially central position in the length direction, a mixing chamber 22 in which the respective flow paths 21a are opened at the same time and the refrigerant is mixed is provided.

As shown in FIG. 2 (a), the flow paths 21a have the same cross-sectional shape, and are separately arranged in the width direction of the heat transfer tube 21. The mixing chamber 22 is shown in FIG.
As shown in (b), it is formed as a flat space straddling all the flow paths 21a.

The heat transfer tube 21 is formed by bonding a pair of plate-like halves 23, 23 as shown in FIG. Here, the pair of plate-like halves 23 constituting the heat transfer tube 21 have the same shape, and are separately manufactured by extrusion molding. A plurality of grooves 24 are formed on one side surface of the plate-shaped half 23 along the length direction, and a recess 25 where these grooves merge together is formed at substantially the center in the length direction. .

The heat transfer tube 21 includes a pair of plate-like halves 23, 23.
Are joined by brazing, but at this time, the channels 24 overlap each other to provide the flow path 21a, and the recesses 25 overlap each other to provide the mixing chamber 22. It is done.

In the condenser provided with the heat transfer tube 21 configured as described above, the refrigerant flows in the respective flow paths 21a all in the same direction (the direction of arrow A in the figure), and the air passes through the condenser in the same direction. (Arrow B in the figure)
Direction).

At this time, as the air proceeds from the inflow surface of the condenser (the left side of the heat transfer tube 21 in FIG. 1) to the outflow surface (the right side of the heat transfer tube 21 in FIG. 1), the temperature of the air increases. However, since the temperature of the refrigerant flowing through the flow path 21a is always constant, the temperature difference between the refrigerant and the air is large on the inflow surface side of the air, and the temperature difference is small on the outflow surface side. As a result, in the heat transfer tube 21, the amount of exchange heat is larger on the inflow surface side of the air than on the outflow surface side, and the refrigerant starts to condense earlier, and the refrigerant flowing on the inflow surface side of the air has a strong liquid phase (liquid rich). ), The refrigerant flowing on the outflow surface side has a strong gas phase (gas rich).

However, the refrigerant flowing through each flow path 21a has a strong liquid phase and a strong gas phase.
2, the mixture is mixed and adjusted to a substantially uniform state, and then distributed to the respective flow paths 21a again.
As a result, the difference in the void ratio (volume ratio between the gas refrigerant and the liquid refrigerant) between the inflow surface side and the outflow surface side is reduced, and each flow path 21
The difference in pressure loss between a becomes smaller.

Therefore, if the heat transfer tube configured as described above is employed, the flow rate of the refrigerant flowing through the plurality of flow paths 21a provided in the heat transfer tube 21 becomes uniform, so that a higher performance condenser can be obtained. Can be

Further, by bonding and joining the pair of plate-like halves 23, 23, it is possible to manufacture the heat transfer tube 21 having a complicated shape having the mixing chamber 22 therein at low cost.

Next, a second embodiment of the heat exchanger according to the present invention will be described with reference to FIGS. The evaporator constituting the car air conditioner has a core portion formed by alternately stacking heat transfer tubes and radiation fins, a gas refrigerant inlet side header provided above the core portion, and a It is configured to include a gas refrigerant outlet header provided at an upper portion, a lower header provided at a lower portion of the core portion to guide a flow of the gas refrigerant in a reverse direction, and the like.

FIG. 4 shows the heat transfer tube 31 constituting the core portion. The heat transfer tube 31 has the appearance of a flat tube having a uniform width and thickness, but a plurality of flow paths 31a through which a refrigerant flows are provided in the heat transfer tube 31 along the length direction. A mixing chamber 32 is provided at a substantially central position where the flow paths 31a are opened all at once and the refrigerant is mixed.

As shown in FIG. 5 (a), each of the flow paths 31a has a substantially triangular cross-sectional shape and an equal cross-sectional area, and is arranged in the width direction of the heat transfer tube 31 by alternately combining upper and lower parts. Further, the mixing chamber 32 is formed as a flat space extending over all the flow paths 31a as shown in FIG. 5B.

As shown in FIG. 6, the heat transfer tube 31 has a pair of plate members 33, 33 having both side edges 33a extending in the longitudinal direction bent toward one side surface facing each other. 2 which is bent in a wavy manner so as to provide a groove in the length direction of
A plurality of corrugated plates 34 are arranged in the longitudinal direction of the plate 33 so as to be spaced apart from each other, and then sandwiched between a pair of plates 33, 33 to be bonded. At this time, the flow path 31a is provided between the plate 33 and the groove of the corrugated plate 34, and the mixing chamber 32 is provided in the gap between the two corrugated plates 34.

In the evaporator provided with the heat transfer tubes 31 configured as described above, the refrigerant flows in all the flow paths 31a in the same direction (the direction of arrow C in the figure), and the air passes through the evaporator in the same direction. (In the direction of arrow D in the figure).

The air inflow surface in the evaporator (FIG. 4)
The temperature of the air decreases from the middle heat transfer tube (left side surface) toward the outflow surface (left side surface of the heat transfer tube in FIG. 4), but the temperature of the refrigerant flowing through the flow path 31a is always constant. Therefore, the temperature difference between the refrigerant and the air is large on the inflow surface side of the air, and the temperature difference is small on the outflow surface side.
As a result, in the heat transfer tube 31, the amount of exchange heat is larger on the inflow surface side of the air than on the outflow surface side, and the refrigerant starts to condense quickly, and the refrigerant flowing on the inflow surface side of the air has a strong gas phase (gas rich). The refrigerant flowing on the outflow surface side has a strong liquid phase (liquid rich).

However, the refrigerant flowing through each flow passage 31a has a strong liquid phase and a strong gas phase.
2, the mixture is mixed and adjusted to a substantially uniform state, and then distributed to the respective flow paths 31a again.
Thereby, the difference in the void ratio between the inflow surface side and the outflow surface side is reduced, and the difference in pressure loss between the respective flow paths 31a is reduced.

Therefore, if the heat transfer tube 31 configured as described above is employed, the flow rate of the refrigerant flowing through the plurality of flow paths 31a provided in the heat transfer tube 31 becomes uniform, so that a more sophisticated evaporator can be provided. can get.

The two corrugated plates 34 are connected to a pair of plate members 3.
By sandwiching and bonding between 3 and 33, the heat transfer tube 31 having a complicated shape and including the mixing chamber 32 therein can be manufactured at low cost.

Incidentally, the condenser is described in the first embodiment and the evaporator is described in the second embodiment. However, the present invention is not limited to various heat exchangers provided in a car air conditioner. It is also applicable to heat exchangers.

[0040]

As described above, according to the heat exchanger of the present invention, a heat transfer tube provided with a plurality of flow paths is provided inside the heat transfer tube.
By providing a mixing chamber in which all the flow paths are opened at the same time, a strong liquid-phase refrigerant flowing in one flow path and a strong gas-phase refrigerant flowing in another flow path are mixed in the mixing chamber. It is arranged in a uniform state, the difference in void ratio is reduced, the difference in pressure loss in each flow pipe is reduced, and the flow rate of the refrigerant flowing through a plurality of flow paths provided in the heat transfer pipe is equalized. Therefore, a higher performance heat exchanger can be obtained.

According to the heat exchanger of the present invention, a heat transfer tube is formed by bonding a pair of plate-like halves, or a plurality of corrugated plates are sandwiched between a pair of plate members and bonded to form a heat transfer tube. With this configuration, a heat transfer tube having a complicated shape having a mixing chamber therein can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is a view showing a first embodiment of a heat exchanger according to the present invention, and is a side view of a heat transfer tube constituting a condenser.

2A is a sectional view taken along line IIa-IIa in FIG. 1, and FIG. 2B is a sectional view taken along line IIb-IIb in FIG.

FIG. 3 is an exploded perspective view of the heat transfer tube of FIG.

FIG. 4 is a view showing a second embodiment of the heat exchanger according to the present invention, and is a side view of a heat transfer tube constituting an evaporator.

5A is a sectional view taken along line Va-Va in FIG. 4, and FIG. 5B is a sectional view taken along line Vb-Vb in FIG.

FIG. 6 is an exploded perspective view of the heat transfer tube of FIG.

FIG. 7 is a side view showing an example of a conventional capacitor.

8 is a sectional view taken along line VIII-VIII in FIG.

9 is a graph showing the air temperature with respect to the distance in the air flow direction in the heat transfer tube 1 of FIG.

FIG. 10 is a side view showing an example of a conventional evaporator.

11 is a sectional view taken along line XI-XI in FIG.

12 is a graph showing the air temperature with respect to the distance in the air flow direction in the heat transfer tube 11 of FIG.

[Explanation of symbols]

 Reference Signs List 21 heat transfer tube 21a flow path 22 mixing chamber 23 plate half 24 groove 25 recess

Claims (3)

[Claims] 1. A heat transfer tube having a plurality of flow paths provided therein along a length direction, an inflow port connected to one end of the heat transfer tube to serve as a fluid inlet, and connected to the other end of the heat transfer tube. And a fin provided in contact with the outer surface of the heat transfer tube to increase the heat exchange efficiency between the fluid and the gas flowing outside the heat transfer tube. A heat exchanger, wherein a mixing chamber in which the plurality of flow paths are opened at the same time and the fluid is mixed is provided inside the heat transfer tube. 2. The heat transfer tube includes a pair of plate-like halves each having a plurality of grooves formed on one side surface along a length direction and having a recess where the grooves merge together. 2. The heat exchanger according to claim 1, wherein the side walls are bonded to each other, the channels are provided by overlapping grooves, and the mixing chamber is provided by overlapping recesses. 3. 3. The heat transfer tube according to claim 1, wherein a pair of plate members whose both side edges along a length direction are bent toward one side face each other, and a groove is provided in a length direction of the plate member. A plurality of corrugated plates bent in a wavy shape are attached and sandwiched between the pair of plate members in a state where they are separated from each other in the longitudinal direction of the plate member. A flow path is provided,
The heat exchanger according to claim 1, wherein the mixing chamber is provided between the corrugated plates.