JPH02258500A - Evaporative heat exchanger - Google Patents

Abstract

PURPOSE:To improve heat exchanger efficiency in an evaporative heat exchanger used for space and the like by disposing a first heat exchanger part provided with a cooling medium flow passage and a cooled medium flow passage adjoiningly at the periphery of an approximately cylindrical second heat exchanger part. CONSTITUTION:This evaporative heat exchanger 1 is formed of a first and a second heat exchanger parts 3, 5, and the first heat exchanger part 3 is formed by providing a cooled medium passage 9 in which a cooled medium (a) flows along the periphery of a first cooling medium passage 7 in which a first cooling medium bb flows, interposing a bulkhead 11. The second heat exchanger part 5 is disposed inside the first heat exchanger part 3 and provided with a cooled medium passage 23 in which the cooled medium (a) flows along the periphery of a cylindrical container 21 as well as a spray nozzle 25 for spraying a second cooling medium (b) above the container 21. The container 21 and the passage 23 are partitioned by a cylinder bulkhead 27. The first cooling medium passage 7 is formed of plural passages approximately in the spiral form, and press the first cooling medium bb to the bulkhead 11 by the centrifugal action.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an evaporative heat exchanger, and particularly to an evaporative heat exchanger used in a microgravity environment such as in a space orbit.

(Prior Art) Heat generated in space orbit devices such as satellites and space stations needs to be exhausted to outer space. Conventionally, a heat sink is often used as a means for discharging heat, but in some cases, the heat sink cannot be used, or the amount of heat dissipated by the heat sink may be less than the required exhaust heat ω. In such a situation, a heat generating means other than a heat sink is required, and one effective heat exhausting means is an evaporative heat exchanger that utilizes the latent heat of vaporization of a cold lJl medium. However, in the evaporative heat exchanger, the cold I
In many cases, the gas phase and liquid phase of the medium are mixed,
In the microgravity environment in space orbit, many types of evaporative heat exchangers used as ground equipment will become difficult to use.

Types that can be used relatively easily in a microgravity environment include the "flash evaporative heat exchanger" that sprays the cooling medium, and the "high-speed forced convection evaporative exchanger 11" that flows the cooling medium at high speed through thin tubes. There are "evaporative heat exchangers with wicks" that separate the heat.

By the way, for example, during a space shuttle like the US Space Shuttle, a part of the body is opened and used as a heat sink, but the heat sink cannot be opened during ascent and return.

For this reason, a heat exhausting means other than a heat sink is required at the time of up-d and return, and an evaporative heat exchanger is used in the space shuttle.

An example of a conventional evaporative heat exchanger similar to the evaporative heat exchanger used in the Space Shuttle is shown in FIG.

The evaporative heat exchanger shown in FIG. 5 is provided with a flow path 103 on the outside of a cylindrical container 101 through which the medium to be cooled a flows.
A spray nozzle 105 for spraying a cold W medium is provided above the container 101, and a spray nozzle 105 is provided above the container 101.
03 by a cylindrical partition wall 107. The cooling medium is then sprayed in a liquid phase into the container 101 from the spray nozzle 105, collides with the inner surface of the cylindrical partition wall 107 of the container 101 at a temperature approximately equal to the saturation temperature in the container 101, and is sprayed through the cylindrical partition wall 107. The medium to be cooled removes heat from the medium a and evaporates. The cooling medium which has evaporated into a gas phase is discharged from a vapor outlet 109 provided below the container 101 to an outlet pipe.

On the other hand, the medium to be cooled a is supplied from the inlet header 111 to the flow path 103, exchanges heat with the cooling medium via the cylindrical partition wall 107, is cooled, and is taken out of the evaporative heat exchanger from the outlet header 113. .

In such an evaporative heat exchanger, the medium a to be cooled flows through the flow path 10.
Although the temperature gradually decreases along the cylindrical partition wall 107, the temperature of the cooling medium is approximately the same at any point on the cylindrical partition wall 107. Therefore, the temperature difference between the cooled medium a and the coolant medium differs at each point on the cylindrical partition wall 107. That is, the temperature difference becomes larger at a point near the inlet header 111 to which the medium to be cooled a is supplied. For this reason, there are large differences in the heat exchanger depending on the location, and the efficiency of the heat exchanger is significantly reduced. In addition, since the temperature of the cooling medium A is lower than the outlet temperature of the cooling medium A, the temperature difference between the cooling medium A and the cooling medium A becomes too large near the inlet header 111 of the cooling medium A. There were problems such as droplets of the W medium vAb being separated from the cylindrical partition wall 107 and causing further deterioration of the performance of the evaporative heat exchanger.

In contrast, by using a plurality of conventional evaporative heat exchangers shown in Fig. 5 and connecting them so that the medium to be cooled flows through each sudden exchanger in turn, the temperature of the cooling medium a can be changed for each evaporator. Change for each heat exchanger. This method can be considered, but in this case, the cylindrical volume 1M101? ! Twelve or more evaporative heat exchangers are lined up, and the volume occupied by the plurality of evaporative heat exchangers becomes large.

As a device mounted on a space orbit device that uses limited space such as a satellite or a space shuttle, an increase in volume is a major drawback and can sometimes be fatal, making it extremely impractical.

(Problems to be Solved by the Invention) As described above, conventional heat exchangers that are effective in a microgravity environment have the risk of becoming larger when trying to increase heat exchange efficiency.

Therefore, an object of the present invention is to provide an evaporative heat exchanger that has high heat exchange efficiency in a microgravity environment and can be configured into two small units.

[Means for Solving the Problems of the Invention] In order to achieve the above object, the present invention provides a method in which a cooling medium and a liquid cooling medium are in contact with each other through a partition wall, and the cooling medium and the liquid cooling medium are in contact with each other through a partition wall. In an evaporative heat exchanger in which a liquid cooling!D medium exchanges heat and the entire flow G or a part of the flow of the cooling medium changes from a liquid phase to a gas phase, a heat exchange section between the cooling medium and the medium to be cooled. is divided into a first heat exchange section and a second heat exchange section, the second heat exchange section is formed into a cylindrical shape, and the first heat exchange section is formed into the cold 71].
The first heat exchange section is formed by a flow path through which the TR body flows, a flow path through which the cooled FA medium flows, and a partition wall between the two flow paths, and the first heat exchange section is installed around the outer periphery of the second heat exchange section. An evaporative heat exchanger was constructed.

(Function) According to the above configuration, heat exchange is performed by the first heat exchange section and the second heat exchange section, so that the heat exchange efficiency of the entire evaporative heat exchange can be improved. It is possible to reduce the volume and downsize.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is an explanatory longitudinal cross-sectional view of an evaporative heat exchanger according to an embodiment of the present invention, and FIG. 2 is a plan view of FIG. 1.

The evaporative heat exchanger 1 includes a first heat exchange section 3 and a second heat exchange section 5.
A heat exchange section 5 is arranged.

The first heat exchange section 3 includes a first heat exchange section 3 through which the first cooling medium bb flows.
A cooled medium flow path 9 through which the cooled medium a flows is provided along the outer periphery of the coolant flow path 7, and both flow paths 7.9 are partitioned off by a partition wall 11. A first coolant inlet header 13 and a first coolant outlet header 15 are provided at the inlet and outlet of the 'PSl cold FiI medium flow path 7, respectively. A cooled medium inlet header 17 and a cooled medium outlet header 19 are installed at the inlet and outlet of the coolant.

As shown in FIG. 3, the first cooling medium flow path 7 according to this embodiment is formed of a plurality of flow paths 7a, 7b, . . . is formed into a substantially spiral shape. By forming the first cooling medium flow path 7 in this manner, centrifugal force acts on the first cooling medium bb, the liquid phase is pressed against the partition wall 11, and heat transfer on the partition wall 11 is promoted.

The second heat exchange section 5 is disposed inside the first heat exchange section 3, and is a cooled medium flow path in which the liquid cooling medium a flows along the outer periphery of the cylindrical container 21, similar to the conventional example. 23 is provided above the container 21, and a spray nozzle 25 for spraying the second cooling medium is provided above the container 21. And container 2
1 and the liquid-cooled TA medium flow path 23 are separated by a cylindrical partition wall 27.

A cooled medium inlet header 29 and a cooled medium outlet header 31 are provided at the inlet and outlet of the cooled medium flow path 23, respectively. It is connected to the outlet header 19 of the cooled medium flow path 9 of the exchange section 3 . Further, a steam outlet 35 is provided below the container 21.

Next, let's talk about the operation of the above embodiment.

The cooled medium a enters the cooled medium flow path 9 from the cooled medium inlet header 17 of the first heat exchange section 3 and flows through the first coolant flow path 7 via the partition wall 11 while flowing through the flow path 9. It exchanges heat with the first cooling medium bb, is cooled, and enters the two cooling medium inlet headers of the second heat exchange section 5 through the connecting pipe 33 from the cooling medium outlet header 19.

On the other hand, the first cooling fA medium bb is connected to the first cooling medium inlet header 13.
The liquid coolant enters the first cooling medium flow path 7 and starts evaporating at a point near the entrance of the flow path 7, and evaporates by taking heat from the liquid cooling IJ medium a flowing in the cooled medium flow path 9 via the partition wall 11. Continue,
At a point near the outlet of the flow path 7, the flow becomes a gas-liquid two-phase flow with a large proportion of the gas phase or a single-phase flow of the gas phase, and is discharged from the first cooling medium outlet header 15 to the outside of the first heat exchange section 3. .

When cooling the medium a to be cooled in this way, the first cooling medium bb in the first cooling medium flow path 7 is mostly a gas-liquid two-phase flow, and due to a loss of 10 degrees of pressure in the flow path 7, the first cooling medium bb in the first cooling medium flow path 7 is By reducing the saturation pressure, the saturation temperature, that is, the first
The temperature of the cooling medium bb also decreases. Therefore, especially in a cooling medium such as water, since the saturation temperature decreases significantly with respect to the decrease in saturation pressure, as shown in FIG. The flow direction of the cooled medium a in the coolant flow path 9 is made to be between the paths, and the pressure loss of the first coolant bb is controlled by an appropriate setting 51 of the first coolant flow path 7. Medium a and first cold IA
The temperature α difference of the medium bb can be made substantially constant across the first heat exchange section 3, and the heat exchange efficiency of the first heat exchange section 3 can be increased.

The cooled medium a, which has undergone a considerable amount of heat exchange in the first heat exchange section 3 in this way, then enters the cooled medium flow path 23 from the cooled medium inlet header 29 of the second heat exchange section 5. While flowing through the flow path 23, heat is exchanged with the second cooling medium through the cylindrical partition wall 27, and the cooled medium is taken out of the evaporative heat exchanger 1 through the cooling medium outlet header 31.

On the other hand, the second cooling medium sprayed into the container 21 from the spray nozzle 25 in a liquid phase is marked with an i on the inner surface of the cylindrical partition wall 27 at a temperature substantially equal to the saturation temperature in the container 21, and the cylindrical partition wall 2
The medium a to be cooled flowing through the liquid cooling fA medium flow path 23 via 7
It absorbs heat and evaporates. The second cooling medium, which has evaporated into a gas phase, is then discharged to the outside of the second heat exchange section 5 through a vapor outlet 35 provided below the container 21.

According to this embodiment, since a considerable amount of heat exchange is performed in the first heat exchange section 3 as described above, the volume of the second heat exchange section 5 is significantly reduced compared to the conventional evaporative heat exchanger. and 'KS1 heat exchange section 3 consists of a first coolant flow path 7, a cooled flow path 9, and a partition wall 11 between both flow paths 7 and 9, and these are connected to the second heat exchange section 5. The volume occupied by the first heat exchange section 3 is almost negligible compared to the volume of the second heat exchange section 5.

Therefore, the overall volume of the evaporative heat exchanger 1 can be significantly reduced, and more specifically, the volume of the evaporative heat exchanger 1 can be reduced significantly.
! ! Compared to the case where a plurality of evaporative heat exchangers are used, the volume can be significantly reduced by replacing two conventional evaporative heat exchangers with one evaporative heat exchanger.

The invention is not limited to the embodiments described above.

For example, as shown in FIG. 4, the first coolant flow path 7 may be configured as reciprocating flow paths 7a, 7b, . . . 7a', 7b-. In this case, the first cooling medium bb flowing through the outward channels 7a, 7b, . . ., which has a large proportion of liquid phase and can be expected to have a high heat transfer coefficient, is brought into contact with the partition wall 11.

In addition, when a high-pressure medium such as ammonia is used as the first cold N1 medium bb, the temperature decrease due to pressure loss is small, so the first cold N1 medium bb in the first heat exchange section 3
It is also possible to configure the flow direction of the first cooling medium bb to be substantially opposite to that of the first cooling medium bb, and to simultaneously utilize the flow of the first cooling medium bb after it becomes a gas phase.

In addition, in the embodiment shown in FIG. 1, the first cooling medium bb and the second cooling medium S are separately supplied to the first heat exchange section 3 J5 and the second heat exchange section 5, respectively, and the gas phase single-phase flow is performed. Alternatively, the first cooling rest bb becomes a gas-liquid two-phase flow in which the gas phase occupies most of the flow.
Although the second cooling medium and the second cooling medium are discharged separately, both the first cooling medium, bb, and the second cooling medium are first supplied to the first heat exchange section 3 to exchange heat with the cooled medium a. It is also possible to create a gas-liquid phase flow with a considerable amount of the liquid phase remaining, which is then guided to the spray nozzle 25 of the second heat exchanger 5 and sprayed into the container 21. In this case, the spray nozzle 25 is replaced with a two-phase flow nozzle.

[Effects of the Invention] As is clear from the above explanation, according to the configuration of the present invention, the heat exchange section for the cooling medium and the medium to be cooled of the evaporative heat exchanger is divided into the first heat exchange section and the second heat exchange section. The second heat exchange part is formed into a substantially cylindrical shape, and the first heat exchange part is formed from a flow path through which a cooling medium flows, a flow path through which a liquid cooling medium flows, and a partition wall between both flow paths. and the first heat exchange section is connected to the first heat exchange section.
Since it is installed on the outer periphery of the heat exchange section, the heat exchange efficiency of the evaporative heat exchanger can be increased, and the volume of the entire evaporative heat exchanger can be significantly reduced.

[Brief explanation of drawings]

FIG. 1 is an explanatory longitudinal cross-sectional view of an evaporative heat exchanger according to an embodiment of the present invention, FIG. 2 is a plan view of FIG. 1, and FIG. 3 is a first heat exchanger of the embodiment shown in FIG. A cross-sectional explanatory diagram showing the flow path of the sampling part,
FIG. 4 is an explanatory cross-sectional view showing the flow path of the first heat exchange section of another embodiment, and FIG. 5 is a cross-sectional view of a conventional evaporative heat exchanger. a...Medium to be cooled b, bb...Cold IJl medium 1...Evaporative heat exchanger 3...First heat exchange section 5...
Second heat exchange section 7... First cooling medium channel 9... Liquid cooling PIl medium channel 11... Partition wall 21... Container (second
heat exchange part)

Claims (2)

[Claims] (1) The cooling medium and the medium to be cooled are in contact with each other through a partition wall,
In an evaporative heat exchanger in which the cooling medium and the medium to be cooled exchange heat and the total flow rate or a part of the flow rate of the cooling medium changes from a liquid phase to a gas phase, a heat exchange section between the cooling medium and the medium to be cooled. is divided into a first heat exchange section and a second heat exchange section, the second heat exchange section is formed in a cylindrical shape, and the first heat exchange section and a flow path through which the cooling medium flows and the medium to be cooled are connected to each other. a flowing channel and a partition wall between both channels, and the first
An evaporative heat exchanger, characterized in that a heat exchange section is installed along the outer periphery of the second heat exchange section. (2) In the evaporative heat exchanger according to claim 1, the cooling medium flow path of the first heat exchange section is formed by a plurality of flow paths, and
An evaporative heat exchanger characterized in that these channels are arranged in a substantially spiral shape along the outer periphery of the second heat exchange section.