Heat exchanger

Abstract

A heat exchanger includes board members layered with each other, and a sintered member. A first passage and a second passage are alternately defined between the layered board members. The sintered member adsorbs or desorbs first fluid flowing through the first passage. Second fluid flowing through the second passage has a pressure higher than that of the first fluid. The sintered member is layered on a first face of the board member defining the first passage. The sintered member is pressurized on the first face of the board member in a direction of layering the board members. All outer periphery of the second passage is sealed.

Description

CROSS REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Application No. 2009-14160.1 filed on Jun. 12, 2009, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a heat exchanger.

2. Description of Related Art

JP-A-2008-107075 discloses a heat exchanger having adsorbent. The heat exchanger has tubes through which heat exchange medium flows. The tubes are inserted into a cylinder shaped casing of the heat exchanger from an upper opening, and are fixed inside of the casing. The adsorbent mixed with copper powder is applied around the tube from the upper opening, and hardened by pressurizing with a tool from the upper opening. The copper powder is sintered in this state, such that the sintered copper powder and an outer circumference face of the tube are metallically bonded. The adsorbent is fixed inside of the sintered copper powder.

However, the copper powder is difficult to be pressurized onto the outer circumference face of the tube with a strong force, because the copper powder and the adsorbent are pressurized in a longitudinal direction of the tube. If the pressurizing is insufficient, the metallic bonding may be weak. In this case, heat transmission performance between the sintered copper powder and the outer circumference face of the tube may be lowered.

SUMMARY OF THE INVENTION

In view of the foregoing and other problems, it is an object of the present invention to provide a heat exchanger.

According to an example of the present invention, a heat exchanger includes a plurality of metal board members and a sintered member. The plurality of metal board members are layered with each other so as to define a core. A first passage and a second passage are alternately defined between the layered board members. A first fluid passes through the first passage, and a second fluid passes through the second passage. The second fluid has a pressure higher than that of the first fluid. The sintered member is made of a sintered mixture of metal powder and adsorbent, and adsorbs or desorbs the first fluid. The board member has a first face defining the first passage and a second face defining the second passage. The sintered member is layered on the first face of the board member. The sintered member is pressurized onto the first face of the board member in a direction of layering the board members. All outer periphery of the second passage is sealed.

Accordingly, heat transmission performance of the heat exchanger can be raised.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present invention will become more apparent from the following' detailed description made with reference to the accompanying drawings. In the drawings:

FIG. 1 is a schematic cross-sectional view illustrating a heat exchanger according to a first embodiment;

FIG. 2 is a schematic plan view illustrating a board member of the heat exchanger of the first embodiment;

FIG. 3 is a schematic cross-sectional view illustrating a heat exchanger according to a second embodiment;

FIG. 4 is a schematic plan view illustrating a first container of the heat exchanger of the second embodiment;

FIG. 5 is a cross-sectional view illustrating a rib of the first container;

FIG. 6 is an exploded perspective view illustrating a heat exchanger according to a third embodiment;

FIG. 7 is an enlarged cross-sectional view taken along line VII-VII of FIG. 6;

FIG. 8 is an enlarged cross-sectional view taken along line VIII-VIII of FIG. 6;

FIG. 9 is a perspective view illustrating a first board member of the heat exchanger of the third embodiment;

FIG. 10 is a perspective view illustrating a second board member of the heat exchanger of the third embodiment;

FIG. 11 is a schematic plan view illustrating a board member of a heat exchanger according to other embodiment;

FIG. 12 is a schematic plan view illustrating a board member of a heat exchanger according to other embodiment;

FIG. 13 is a schematic cross-sectional view illustrating an adsorption module of a heat exchanger according to other embodiment;

FIG. 14 is a schematic cross-sectional view illustrating an adsorption module of a heat exchanger according to other embodiment;

FIG. 15 is a schematic cross-sectional view illustrating a heat exchanger according to other embodiment;

FIG. 16 is a schematic cross-sectional view illustrating a core of a heat exchanger according to other embodiment; and

FIG. 17 is a schematic cross-sectional view illustrating a core of a heat exchanger according to other embodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

First Embodiment

A heat exchanger 100 of a first embodiment will be described with reference to FIGS. 1 and 2.

The heat exchanger 100 is used for exchanging heat between adsorbent contained in a sintered member 120 and heat exchange medium passing through a second passage 190. When water is evaporated into water vapor to be adsorbed by the adsorbent, the heat exchange medium is cooled by latent heat generated by the evaporation. In contrast, when the adsorbent is heated by a high temperature heat exchange medium, the adsorbed water vapor is desorbed from the adsorbent. The water vapor represents first fluid, and may correspond to gas phase medium to be adsorbed. The evaporated water may correspond to liquid phase medium to be adsorbed. The heat exchange medium represents second fluid.

As shown in FIG. 1, the heat exchanger 100 has a heat exchange portion 101, a casing 130, a lid 131, a communication tube 150, an inlet tube 160 and an outlet tube 170. In the heat exchange portion 101, first fluid and second fluid exchange heat with each other. The casing 130 accommodates the heat exchange portion 101. The lid 131 closes an opening of the casing 130. The communication tube 150 is connected to the casing 130. The inlet tube 160 and the outlet tube 170 are connected to the heat exchange portion 101.

The heat exchange portion 101 is defined by layering plural board members 110. As shown in FIG. 2, the board member 110 has a circular shape, and is made of metal such as copper. All outer circumference of the board member 110 has a connecting portion 111. The connecting portion 111 is a ring-shaped plane. The board member 110 has a recess 112 recessed in a direction of layering the board members 110. The recess 112 is located on an inner side of the connecting portion 111, and all the recess 112 is surrounded by the connecting portion 111. A bottom 113 of the recess 112 is constructed by a circular plane, and has a main outer surface 114. The outer surface 114 corresponds to an outer face of the recess 112, and is located on the recess side of the recess 112 in the recess direction. The recess 112 of FIG. 2 approximately perpendicularly protrudes from the connecting portion 111.

The bottom 113 has two of communication parts 115, 116 having a circular opening. The communication parts 115, 116 are located in a manner that a distance between the communication parts 115, 116 becomes longest in the bottom 113. As shown in FIG. 1, the communication part 115, 116 protrudes toward a direction further recessed from the bottom 113. That is, the communication part 115, 116 protrudes outward from the bottom 113.

The sintered member 120 is bonded to all the outer surface 114 of the bottom 113, and is produced by sintering metal powder. The sintered member 120 is formed by sintering a mixture in which metal powder is mixed with adsorbent. The sintered member 120 is metallically bonded with the outer surface 114, and corresponds to a heat transmitting member. The sintered member 120 receives heat from the outer surface 114, or radiates heat to the outer surface 114. For example, the metal powder may be made of copper powder. The sintered member 120 has a uniform thickness smaller than a protrusion height of the communication part 115, 116.

The adsorbent (not shown) contained in the sintered member 120 is made of a porous member having minute openings inside. For example, the adsorbent is made of silica gel. Gas phase first fluid is adsorbed or desorbed by the adsorbent. For example, gas phase water corresponding to water vapor is adsorbed or desorbed by the adsorbent. If the adsorbent receives heat from the sintered member 120, temperature of the adsorbent is raised. At this time, the adsorbent adsorbs gas phase first fluid. If the adsorbent emits heat to the sintered member 120, temperature of the adsorbent is lowered. At this time, the adsorbent desorbs gas phase first fluid.

A pair of the board members 110 defines an adsorption module 103, in a manner that the bottoms 113 of the board members 110 oppose to each other. The board members 110 of the module 103 are layered in a state that the outer surfaces 114 are located outside of the module 103. Specifically, the board members 110 are connected in a state that the connecting portions 111 are contact with each other.

A first passage 180 is defined to be separated from the second passage 190. First fluid flows through the first passage 180, and second fluid flows through, the second passage 190. That is, the second passage 190 is defined by an inside of the module 103, and is located between the communication parts 115, 116. Due to the connecting portion 111, all the outer circumference of the second passage 190 is sealed in a cross-section perpendicular to a flowing direction of the second fluid. The sintered member 120 is arranged outside of the adsorption module 103.

The connecting portions 111 are connected by brazing. A metal fin 140 is arranged inside of the module 103, and is metallically bonded to an inner face of the module 103.

The heat exchange portion 101 is defined by layering a plurality of the modules 103, in a manner that the outer surfaces 114 oppose to each other. The modules 103 are integrated through a brazing by connecting the communication parts 115 to each other and by connecting the communication parts 116 to each other in a contact state. Thus, the first passage 180 and the second passage 190 are separated from each other. That is, the first passage 180 is defined between the modules 103.

A communication passage 181 is defined between the sintered members 120, thereby first fluid can communicate with all the sintered member 120.

The heat exchange portion 101 is constructed by layering the modules 103, and includes a core 102, a distribution tank 104 and a gather tank 105. Due to the core 102, heat of second fluid is transmitted to the adsorbent through the outer surface 114 and the sintered member 120. Thus, temperature of the adsorbent is raised. Further, due to the core 102, heat of the adsorbent is transmitted to second fluid through the sintered member 120 and the outer surface 114. Thus, temperature of the adsorbent is lowered.

The distribution tank 104 corresponds to a header tank, and makes the communication parts 115 to communicate with each other. The inlet tube 160 is connected to the distribution tank 104 in the layering direction of the board members 110. The inlet tube 160 introduces second fluid into the heat exchange portion 101. The distribution tank 104 distributes second fluid flowing from the inlet tube 160 into the second passages 190 of the core 102.

The gather tank 105 corresponds to a header tank, and makes the communication parts 116 to communicate with each other. The outlet tube 170 is connected to the gather tank 105 in the layering direction of the board members 110. The outlet tube 170 discharges second fluid from the heat exchange portion 101. The gather tank 105 gathers second fluid passing through the second passages 190, and makes the gathered fluid to flow out through the outlet tube 170.

Second fluid flowing through the inlet tube 160 is distributed into the second passages 190, due to the distribution tank 104. Second fluid passing through the second passages 190 is gathered in the gather tank 105, and the gathered fluid flows out through the outlet tube 170. The second passage 190 is defined between the board members 110, and an inner space between the board members 110 is sealed from outside by the connecting portions 111.

Due to the heat exchange portion 101, heat is exchanged between second fluid passing through the second passages 190 and first fluid passing through the first passages 180. The casing 130 is a box member having a base, and accommodates the heat exchange portion 101. The base of the casing 130 has a circular shape. An inner face of the casing 130 is not contact with the heat exchange portion 101.

A communication space 182 is defined between the inner face of the casing 130 and the heat exchange portion 101. First fluid flows in the communication space 182. The first passage 180 may be defined by the communication space 182 and the communication passage 181. The casing 130 has an opening located adjacent to the inlet tube 160 and the outlet tube 170. An edge of the opening has a flange shape.

The lid 131 has a flat board shape, and is connected to the flange-shaped opening of the casing 130. Thus, the opening of the casing 130 is closed by the lid 131. The tubes 150, 160, 170 penetrating the lid 131 are fixed to the lid 131. The lid 131 supports the heat exchange portion 101 through the tubes 160, 170.

Due to the communication tube 150, the communication space 182 and a storage tank (not shown) can communicate with each other. Liquid phase first fluid is stored in the storage tank. Gas phase first fluid flows between the casing 130 and the storage tank through the tube 150. The lid 131 closes the opening of the casing 130, thereby the first passage 180 has an approximately vacuum state in the casing 130.

The sintered member 120 is produced by performing a mold process and a heat process. Metal powder is pressurized onto the board member 110, in the mold process. The metal powder is bonded with each other by being heated at a temperature equal to or lower than a melting temperature of the metal powder in the heat process. In the mold process, the metal powder is pressurized in a direction approximately perpendicular to the outer surface 114 of the board member 110. That is, the sintered member 120 is produced on the outer surface 114 by being pressurized in the layering direction of the board members 110.

An operation of the heat exchanger 100 will be described. Second fluid corresponds to a heat source of the heat exchanger 100, and flows into the distribution tank 104 through the inlet tube 160. Second fluid is distributed into the second passages 190 of the modules 103 from the distribution tank 104. The second passage 190 is defined between the board members 110, and all the outer circumference of the second passage 190 is sealed from outside in a cross-section perpendicular to the flowing direction of second fluid.

Second fluid flows through the second passage 190, and emits heat to the bottom 113 and the fin 140. After the heat emission, second fluid gathers into the gather tank 105. Therefore, temperature of the second fluid gathered in the gather tank 105 is lower than that in the distribution tank 104. Second fluid gathered into the gather tank 105 flows out of the heat exchanger 100 through the outlet tube 170.

Heat is received by the bottom 113 and the fin 140 from the second fluid, and the received heat is transmitted to the sintered member 120 through the outer surface 114. Further, the received heat is further transmitted to the adsorbent held in the sintered member 120. Thus, temperature of the adsorbent is raised, and the adsorbent adsorbs gas phase first fluid flowing through the first passage 180.

Specifically, the adsorbent located between the modules 103 adsorbs first fluid flowing through the communication passage 181. Adsorbent located most outer side of the heat exchanger 100 adsorbs first fluid flowing through the communication space 182. Gas phase first fluid flowing in the casing 130 is adsorbed by the adsorbent. Therefore, liquid phase first fluid stored in the storage tank is evaporated, and the evaporated fluid flows into the casing 130 through the communication tube 150.

A cold energy storage portion may be arranged in the storage tank so as to store cold energy generated when first fluid is evaporated. The cold energy can be recovered by coolant to cool an internal combustion engine, for example.

If the flowing of second fluid is stopped, temperature of the adsorbent is lowered. In this case, the adsorbent desorbs gas phase first fluid. The desorbed fluid is condensed in the storage tank, and the condensed fluid is stored in the storage tank in the liquid state.

The adsorbent contained in the sintered member 120 is not bonded with the metal powder or the board member 110. Therefore, the adsorbent may limit the bonding between the metal powder and the outer surface 114 of the board member 110. However, according to the first embodiment, the bonding between the metal powder and the outer surface 114 of the board member 110 can be enhanced, because the sintered member 120 is produced by being pressurized to the outer surface 114 in the perpendicular direction. Further, bonding among the metal powder can be enhanced. Thus, heat transmission performance between the outer surface 114 and the sintered member 120 can be improved.

The core 102 is separated into the second passages 190 by the board members 110, and second fluid flows in the core 102 in the separated state. Therefore, the core 102 can be produced by using thinner board members 110, compared with a case in which a large amount of second fluid flows in a single second passage of a core. Thus, a weight of the heat exchanger 100 can be reduced.

The heat exchanger 100 has the fin 140 located in the second passage 190, and the fin 140 is connected with the board member 110. The second passage 190 may have an expansion deformation, if a pressure difference is generated between the first passage 180 and the second passage 190. However, due to the fin 140, the expansion deformation of the second passage 190 can be reduced.

The outer surface 114 may correspond to a first face of the board member 110. A reverse face of the board member 110 opposite from the outer surface 114 may correspond to a second face of the board member 110.

Second Embodiment

A heat exchanger 200 of a second embodiment will be described with reference to FIGS. 3 and 4.

In each subsequent embodiment, the same reference number is given to the same component as the first embodiment, and its explanation is omitted. Points and features different from the first embodiment will be described.

Heat is exchanged between first fluid and second fluid in the heat exchanger 200. The heat exchanger 200 has a heat exchange portion 201, a communication tube 250, an inlet tube 260 and an outlet tube 270. Heat is exchanged between first fluid and second fluid in the heat exchange portion 201. The tubes 250, 260, 270 are connected to the heat exchange portion 201. First fluid may correspond to water, and the second fluid may correspond to coolant to cool an internal combustion engine (not shown).

The heat exchange portion 201 is constructed by layering plural adsorption modules 203. The module 203 has a first container 210a and a second container 210b. As shown in FIG. 4, the first container 210a has an approximately rectangular tube shape, and is made of metal such as copper. All outer periphery of the first container 210a has a first connecting portion 211a. As shown in FIG. 3, the first connecting portion 211a extends in a layering direction of the modules 203, and an inner dimension of the first container 210a is enlarged as the first connecting portion 211a extends toward a first end of the layering direction.

The first container 210a has a first bottom 213a located on an inner side of the first connecting portion 211a. All outer periphery of the first bottom 213a is surrounded by the first connecting portion 211a. As shown in FIG. 4, the first bottom 213a has first communication parts 215a, 216a, 217a. The first communication parts 215a, 216a are located in a manner that a distance between the first communication parts 215a, 216a becomes longest in the first bottom 213a.

The first communication parts 215a, 216a define a part of a second passage 290 through which second fluid flows. The first communication part 215a, 216a has an opening, and protrudes toward the first end of the layering direction from the first bottom 213a.

The first communication part 217a defines a part of a first passage 280 through which first fluid flows. The first communication part 217a has an opening, and protrudes toward a second end of the layering direction from the first bottom 213a.

The first bottom 213a has plural first ribs 240a. The first rib 240a has a circular shape, and protrudes from the first bottom 213a toward the first end of the layering direction. As shown in FIG. 4, the first ribs 240a construct rows and columns on the first bottom 213a.

A sintered member 220 is arranged on all first end face 214a of the bottom 213a, and is produced by sintering metal powder. The sintered member 220 is metallically bonded with the first end face 214a, and corresponds to a heat transmitting member. The sintered member 120 receives heat from the first end face 214a, or radiates heat to the first end face 214a. For example, the metal powder is made of copper powder. The sintered member 220 has a thickness smaller than a height of the first connecting portion 211a.

A communication passage 281 is defined over all areas of the sintered member 220, and gas phase first fluid flows through the communication passage 281. As shown in FIG. 4, the communication passage 281 has a net shape. The sintered member 220 has an area surrounded by the communication passage 281, and a circular recess 221 is defined at a center position of the area. The recess 221 is defined for a second rib 240b of a second bottom 213b of the second container 210b.

The sintered member 220 may be made of a porous member having minute openings (not shown) inside, and adsorbent is held in the openings. The sintered member 220 is produced by being sintered in this state. Gas phase first fluid is adsorbed or desorbed by the adsorbent. For example, gas phase water corresponding to water vapor is adsorbed or desorbed by the adsorbent such as silica gel.

If the adsorbent receives heat from the sintered member 220, temperature of the adsorbent is raised. At this time, the adsorbent adsorbs the gas phase first fluid.

If the adsorbent emits heat to the sintered member 220, temperature of the adsorbent is lowered. At this time, the adsorbent desorbs the gas phase first fluid.

Similarly to the first container 210a, all outer periphery of the second container 210b has a second connecting portion 211b. As shown in FIG. 3, the second connecting portion 211b extends in the layering direction of the modules 203, and has a rectangular tube shape. An inner dimension of the second container 210b is enlarged, as the second connecting portion 211b extends toward the first end of the layering direction.

The second container 210b has the second bottom 213b located on an inner side of the second connecting portion 211b. All outer periphery of the second bottom 213b is surrounded by the second connecting portion 211b. The second bottom 213a has second communication parts 215b, 216b, 217b. The second communication parts 215b, 216b are located in a manner that a distance between the second communication parts 215b, 216b becomes longest on the second bottom 213b.

The second communication parts 215b, 216b define a part of the second passage 290 through which second fluid flows. The second communication part 215b, 216b has an opening, and protrudes toward the second end of the layering direction from the second bottom 213b.

The second communication part 217b defines a part of the first passage 280 through which first fluid flows. The second communication part 217b has an opening, and protrudes toward the first end of the layering direction from the second bottom 213b.

The second bottom 213b has plural second ribs 240b. The second rib 240b has a circular shape, and protrudes from the second bottom 213b toward the second end of the layering direction. The second ribs 240b construct rows and columns on the second bottom 213b.

The first container 210a and the second container 210b define the adsorption module 203, in a manner that the bottoms 213a, 213b of the containers 210a, 210b oppose to each other. The end faces 214a, 214b of the containers 210a, 210b are located outside of the module 203.

Specifically, the containers 210a, 210b are connected by a brazing in a state that the connecting portions 211a, 211b of the containers 210a, 210b are contact with each other. Thus, the first passage 280 and the second passage 290 can be separated from each other. The communication parts 217a, 217b of the containers 210a, 210b are connected with each other through a brazing.

The second passage 290 is defined between the communication part 215a, 215b and the communication part 216a, 216b in the module 203. Due to the connecting portion 211a, 211b, all the outer periphery of the second passage 290 is sealed in a cross-section perpendicular to the flowing direction of second fluid. The sintered member 220 is arranged outside of the adsorption module 203.

The heat exchange portion 201 is defined by layering a plurality of the modules 203. At this time, the first end face 214a of the first container 210a opposes to the second end face 214b of the second container 210b located adjacent to the first container 210a.

Specifically, the modules 203 are connected by a brazing in a state that the connecting portions 211a, 211b are contact with each other. Further, the communication part 215a, 216a of the first container 210a and the communication part 215b, 216b of the second container 210b are made to communicate with each other through a brazing connection.

The modules 203 are layered in a state that the first rib 240a and the second rib 240b are contact with each other. That is, the second rib 240.b of the second container 210b is inserted into the recess 221 of the first container 210a, such that the second rib 240b and the first rib 240a are contact with each other. The sintered member 220 is metallically bonded with the first end face 214a of the first container 210a and the second end face 214b of the second container 210b.

The first passage 280 is defined between the modules 203 by layering the modules 203. Specifically, the first passage 280 is defined between the first end face 214a of the first container 210a and the second end face 214b of the second container 210b.

The heat exchange portion 201 is constructed by layering the modules 203, and has a core 202, a distribution tank 204, a gather tank 205 and a communication tank 206.

In the core 202, heat of second fluid is transmitted to the adsorbent through the bottom 213a, 213b and the sintered member 220. Thus, temperature of the adsorbent is raised. Further, heat of the adsorbent is transmitted to second fluid through the sintered member 220 and the bottom 213a, 213b. Thus, temperature of the adsorbent is lowered.

The core 202 is separated into the second passages 290 by the containers 210a, 210b. That is, all outer periphery of the second passage 290 is sealed in a cross-section perpendicular to the flowing direction of the second fluid. Due to the heat exchange portion 201, heat is exchanged between the second fluid passing through the second passages 290 of the core 202 and the first fluid passing through the first passages 280 of the core 202.

The distribution tank 204 corresponds to a header tank making the communication parts 215a, 215b of the modules 203 to communicate with each other. The inlet tube 260 is connected to the distribution tank 204 in the layering direction of the modules 203. The inlet tube 260 introduces the second fluid into the heat exchange portion 201. The distribution tank 204 distributes the second fluid flowing from the inlet tube 260 into the second passages 290 of the core 202.

The gather tank 205 corresponds to a header tank making the communication parts 216a, 216b of the modules 203 to communicate with each other. The outlet tube 270 is connected to the gather tank 205 in the layering direction of the modules 203. The outlet tube 270 discharges the second fluid from the heat exchange portion 201. The gather tank 205 gathers the second fluid passing through the second passages 290 of the core 202, and makes the gathered fluid to flow out through the outlet tube 270.

The communication tank 206 corresponds to a header tank making the communication parts 217a, 217b of the modules 203 to communicate with each other. The communication tube 250 is connected to the communication tank 206 in the layering direction of the modules 203. The communication tank 206 corresponds to a tube member to supply first fluid to the heat exchanger 200, or to discharge first fluid from the heat exchanger 200.

The communication tube 250 makes the communication tank 206 and a storage tank (not shown) to communicate with each other. Liquid phase first fluid is stored in the storage tank. Gas phase first fluid flows through the communication tube 250 between the communication tank 206 and the storage tank. The first passage 280 has an approximately vacuum state.

The sintered member 220 is produced by performing a mold process and a heat process. Metal powder is pressurized onto the containers 210a, 210b, in the mold process. The metal powder is bonded with each other by being heated at a temperature equal to or lower than a melting temperature of the metal powder in the heat process. In the mold process, the sintered member 220 is pressurized in a direction perpendicular to the end faces 214a, 214b of the containers 210a, 210b. That is, the sintered member 220 is pressurized onto the end faces 214a, 214b of the containers 210a, 210b in the layering direction of the containers 210a, 210b.

An operation of the heat exchanger 200 will be described. Second fluid corresponds to a heat source of the heat exchanger 200, and flows into the distribution tank 204 through the inlet tube 260. Second fluid is distributed into the second passages 290 of the modules 203 from the distribution tank 204 The second passage 290 is defined by the containers 210a, 210b, and all periphery of the second passage 290 is sealed in a cross-section perpendicular to the flowing direction of the second fluid.

The second fluid flows through the second passage 290 of the core 202, and emits heat to the bottom 213a, 213b. After the heat emission, the second fluid gathers in the gather tank 205. Therefore, temperature of the second fluid gathered in the tank 205 is lower than that in the distribution tank 204. The second fluid gathered in the tank 205 flows out of the heat exchanger 200 through the outlet tube 270.

Heat is received by the bottom 213a, 213b from the second fluid, and the received heat is transmitted to the sintered member 220 through the end face 214a, 214b. Further, the received heat is further transmitted to the adsorbent held in the sintered member 220. Thus, temperature of the adsorbent is raised. The adsorbent adsorbs the gas phase first fluid flowing through the first passage 280.

Specifically, the sintered member 220 is located between the modules 203, and the adsorbent held in the sintered member 220 adsorbs the first fluid flowing through the communication passage 281. The gas phase first fluid flowing in the first passage 280 is adsorbed by the adsorbent. Therefore, the liquid phase first fluid stored in the storage tank is evaporated, and the evaporated fluid flows into the communication tank 206 through the communication tube 250.

A cold energy storage portion may be arranged in the storage tank so as to store cold energy generated when the first fluid is evaporated. Thus, cold energy can be recovered by coolant to cool an internal combustion engine. For example, when the flowing of the second fluid in the second passage 290 is stopped, temperature of the adsorbent is lowered. In this case, the adsorbent desorbs the gas phase first fluid. The desorbed gas phase first fluid is condensed in the storage tank, and the condensed fluid is stored in the storage tank in the liquid state.

The heat exchanger 200 has the heat process in a state that the sintered member 220 is pressurized to the end face 214a, 214b of the bottom 213a, 213b in the perpendicular direction. Therefore, bonding points among the metal powder and bonding points between the metal powder and the end face 214a, 214b are increased. Thus, heat transmission performance between the end face 214a, 214b and the sintered member 220 can be increased.

According to the second embodiment, the casing 130 of the heat exchanger 100 of the first embodiment is unnecessary. Thus, material cost and weight of the heat exchanger 200 can be reduced.

The core 202 is separated into the second passages 290 by the containers 210a, 210b, and second fluid flows through the core 202 in a separated state. Therefore, the core 202 can be produced by using thinner containers 210a, 210b, compared with a case in which a core has a single second passage through which a large amount of second fluid flows. Thus, weight of the heat exchanger 200 can be reduced.

The heat exchanger 200 has the ribs 240a, 240b contacting with each other. Therefore, an expansion deformation of the second passage 290 can be reduced, if the expansion deformation is generated by a pressure difference between the first passage 280 and the second passage 290.

Advantages of the ribs 240a, 240b will be described with reference to FIG. 5 showing a cross-section of the rib 240a, 240b. The sintered member 220 has a volume shown in a dashed line of FIG. 5, before the sintered member has a sintering. After having the sintering, the volume of the sintered member 220 is contracted into a solid line of FIG. 5. Arrows of FIG. 5 show directions of the contraction, and a center of the contraction corresponds to the rib 240a, 240b.

Therefore, metal powder more approaches the rib 240a, 240b, and the number of bonding points between the metal powder and the end face 214a, 214b can be increased. Thus, heat transmission performance can be further raised.

The container 210a, 210b may correspond to a board member, and the end face 214a, 214b may correspond to a first face of the board member.

Third Embodiment

A heat exchanger 300 of a third embodiment will be described with reference to FIGS. 6-10.

The heat exchanger 300 has cross-sections of FIGS. 7 and 8, when the heat exchanger 300 of FIG. 6 is assembled.

The heat exchanger 300 has a heat exchange portion 301. In the heat exchange portion 301, heat is exchanged between first fluid and second fluid. The first fluid may correspond to water, and the second fluid may correspond to coolant to cool an internal combustion engine (not shown).

The heat exchange portion 301 is defined by layering plural board members 310a, 310b. As shown in FIGS. 9 and 10, the board member 310a, 310b has a rectangular shape, and is made of metal such as copper. A connecting portion 311a, 311b is formed around all outer periphery of the board member 310a, 310b. As shown in FIG. 7, the connecting portion 311a, 311b extends toward a first end of the layering direction, and has a rectangular tube shape.

As shown in FIG. 8 indicating inside cross-section of the heat exchange portion 301, a recess 312a, 312b and a projection 313a, 313b are alternately and successively formed in a left-and-right direction. All peripheries of the recess 312a, 312b recessed in the layering direction and the projection 313a, 313b projected in the layering direction are surrounded by the connecting portion 311a, 311b. The recess 312a, 312b and the projection 313a, 313b extend in a communication direction. The communication direction is defined to be approximately perpendicular to the layering direction and the left-and-right direction.

As shown in FIG. 8, a left-and-right width of a bottom of the recess 312a of the first board member 310a is larger than that of a top of the projection 313a of the first board member 310a. A left-and-right width of a bottom of the recess 312b of the second board member 310b is smaller than that of a top of the projection 313b of the second board member 310b.

A sintered member 320 is arranged on an inner side of the first recess 312a of the first board member 310a, and on an inner side of the second projection 313b of the second board member 310b. The sintered member 320 is produced by sintering metal powder. The sintered member 320 is metallically bonded with an inner face 314a of the first recess 312a of the first board member 310a and an inner face 314b of the second projection 313b of the second board member 310b.

The sintered member 320 corresponds to a heat transmitting member to receive heat from the inner face 314a, 314b, or to radiate heat to the inner face 314a, 314b. For example, the metal powder may be made of copper powder. The sintered member 320 has a uniform thickness smaller than heights of the recess 312a and the projection 313b.

The sintered member 320 is a porous member having minute openings (not shown) inside, and adsorbent is held in the openings. The sintered member 320 is produced by being sintered in this state. Gas phase first fluid is adsorbed or desorbed by the adsorbent. For example, gas phase water corresponding to water vapor is adsorbed or desorbed by the adsorbent such as silica gel.

If the adsorbent receives heat from the sintered member 320, temperature of the adsorbent is raised. At this time, the adsorbent adsorbs the gas phase first fluid. If the adsorbent emits heat to the sintered member 320, temperature of the adsorbent is lowered. At this time, the adsorbent desorbs the gas phase first fluid.

As shown in FIGS. 9 and 10, the recess 312a, 312b and the projection 313a, 313b are not arranged on end portions of the board member 310a, 310b. Communication parts 315a, 316a, 317a, 318a are arranged on the end portions of the board member 310a in the communication direction, and communication parts 315b, 316b, 317b, 318b are arranged on the end portions of the board member 310b in the communication direction. The communication part 315a-318a, 315b-318b has an ellipse opening.

As shown in FIG. 7, the communication part 315a, 315b is located on a distribution side of the communication direction so as to define a distribution tank 304, and the communication part 317a, 317b is located on a gather side of the communication direction so as to define a communication tank 306. Similarly, the communication part 318a, 318b is located on the distribution side so as to define a communication tank 307, and the communication part 316a, 316b is located on the gather side so as to define a gather tank 305.

As shown in FIG. 6, the distribution tank 304 is located on a right side in the left-and-right direction, and the communication tank 307 is located on a left side in the left-and-right direction. The communication tank 306 is located on the right side, and the gather tank 305 is located on the left side.

As shown in FIGS. 7, 9 and 10, the communication part 315a, 316a, 317b, 318b opens and protrudes toward the first end of the layering direction. The communication part 315b, 316b, 317a, 318a opens and protrudes toward the second end of the layering direction.

An adsorption module 303 is constructed by layering a pair of the board members 310a, 310b. At this time, as shown in FIG. 8, the bottom of the recess 312a and the top of the projection 313b oppose to each other, and are contact with each other.

Specifically, the board members 310a, 310b are connected by a brazing. At this time, the connecting portions 311a, 311b are contact with each other, and the communication part 315a, 316a, 317a, 318a is contact with the communication part 315b, 316b, 317b, 318b. Further, the bottom of the recess 312a and the top of the projection 313b are connected through a brazing. Thus, a first passage 380 and a second passage 390 are separated from each other. First fluid flows through the first passage 380, and second fluid flows through the second passage 390.

The second passage 390 is defined by inside of the module 303. Specifically, the second passage 390 is separated by the recess 312b and the projection 313a. All periphery of the second passage 390 is sealed in a cross-section perpendicular to a flowing direction of the second fluid, because the recess 312a and the projection 313b are connected with each other. The sintered member 320 is arranged outside of the adsorption module 303.

The heat exchange portion 301 is defined by layering a plurality of the modules 303. The top of the projection 313a of a subject module 303 is brazed to the bottom of the recess 312b of an upper module 303 located above the subject module 303. The bottom of the recess 312b of the subject module 303 is brazed to the top of the projection 313a of a lower module 303 located under the subject module 303. The communication parts 315a, 315b are integrated through a brazing connection, and the communication parts 316a, 316b are integrated through a brazing connection.

Due to the modules 303, the first passage 380 and the second passage 390 are separated from each other. The first passage 380 is defined between the modules 303, and two layers of the sintered member 320 are arranged in the first passage 380. The sintered member 320 is not arranged end portions of the heat exchange portion 301 in the layering direction.

The two layers of the sintered member 320 are located not to be contact with each other. That is, a communication passage 381 is defined between the two layers of the sintered member 320. Due to the passage 381, first fluid can communicate over all the sintered member 320.

As shown in FIG. 6, the heat exchange portion 301 is constructed by layering the modules 303, and has a core 302, the distribution tank 304, the gather tank 305 and the communication tanks 306, 307.

The core 302 has the recess 312a, 312b and the projection 313a, 313b, and heat of second fluid is transmitted to the adsorbent through the sintered member 320. Thus, temperature of the adsorbent is raised. Further, heat of the adsorbent is transmitted to second fluid through the sintered member 320. Thus, temperature of the adsorbent is lowered.

The core 302 is separated into the second passages 390 by the board members 310a, 310b. Due to the projection 313a and the recess 312b, all periphery of the second passage 390 is sealed in a cross-section perpendicular to a flowing direction of second fluid. In the heat exchange portion 301, heat is exchanged between second fluid passing through the second passages 390 and first fluid passing through the first passages 380.

The distribution tank 304 corresponds to a header tank making the communication parts 315a, 315b to communicate with each other. The distribution tank 304 distributes the second fluid into the second passages 390 of the core 302.

The gather tank 305 corresponds to a header tank making, the communication parts 316a, 316b to communicate with each other. The gather tank 305 gathers the second fluid passing through the second passages 390 of the core 302, and makes the gathered fluid to flow out of the heat exchange portion 301.

The communication tank 306 corresponds to a header tank making the communication parts 317a, 317b to communicate with each other. The communication tank 307 corresponds to a header tank making the communication parts 318a, 318b to communicate with each other. The communication tank 306, 307 makes the first passage 380 and a storage tank (not shown) to communicate with each other. The first fluid having a liquid phase is stored in the storage tank. The first passage 380 has an approximately vacuum state.

The sintered member 320 is produced by performing a mold process and a heat process. Metal powder is pressurized onto the board member 310a, 310b, in the mold process. The metal powder is bonded with each other by being heated at a temperature equal to or lower than a melting temperature of the metal powder in the heat process.

In the mold process, the sintered member 320 is pressurized in a direction perpendicular to the inner face 314a of the recess 312a of the first board member 310a. Further, the sintered member 320 is pressurized in a direction perpendicular to the inner face 314b of the projection 313b of the second board member 310b. That is, the sintered member 320 is pressurized in the layering direction of the board members 310a, 310b.

An operation of the heat exchanger 300 will be described. The second fluid corresponds to a heat source of the heat exchanger 300. The second fluid flows into the distribution tank 304 of the heat exchange portion 301. The second fluid is distributed into the second passages 390 of the modules 303 from the distribution tank 304. The second fluid is separated into the second passages 390 from the distribution tank 304.

Due to the projection 313a and the recess 312b, all periphery of the second passage 390 is sealed in a cross-section perpendicular to the flowing direction of second fluid. The second fluid flows through the second passage 390 of the core 302, and emits heat to the recess 312 and the projection 313. After the heat emission, the second fluid gathers in the gather tank 305 so as to flow out of the heat exchange portion 301. Therefore, temperature of the second fluid gathered in the tank 305 is lower than that in the distribution tank 304.

Heat is received by the recess 312 and the projection 313 from the second fluid, and the received heat is transmitted to the sintered member 320. Further, the received heat is transmitted to the adsorbent held in the sintered member 320. Thus, temperature of the adsorbent is raised. The adsorbent adsorbs the gas phase first fluid flowing in the first passage 380.

Specifically, the sintered member 320 is located between the modules 303, and the adsorbent is held in the sintered member 320. The adsorbent adsorbs the first fluid flowing in the communication passage 381. The gas phase first fluid of the communication passage 381 is adsorbed by the adsorbent. Therefore, the liquid phase first fluid stored in the storage tank is evaporated, and the evaporated fluid flows into the communication passage 381 through the tank 306, 307.

A cold energy storage portion may be arranged in the storage tank so as to store cold energy generated when the first fluid is evaporated. Thus, cold energy can be recovered by coolant to cool an internal combustion engine. For example, when the flowing of the second fluid is stopped, temperature of the adsorbent is lowered. In this case, the adsorbent desorbs the gas phase first fluid. The desorbed gas phase first fluid is condensed in the storage tank, and the condensed fluid is stored in the storage tank in the liquid state.

The method of producing the heat exchanger 300 includes the heat process, after the sintered member 320 is pressurized in a direction perpendicular to the bottom of the recess 312a and the top of the projection 313b. In this case, more metal powder is located adjacent to the bottom of the recess 312a and the top of the projection 313b. Therefore, the number of bonding points between the metal powder and the recess 312a of the first board member 310a is increased. Further, the number of bonding points between the metal powder and the projection 313b of the second board member 310b is increased. Furthermore, bonding areas of the bonding points are increased.

Therefore, heat transmission performance between the recess 312a and the sintered member 320, and heat transmission performance between the projection 313b and the sintered member 320 can be increased. The inner face 314a of the bottom of the first recess 312a of the first board member 310a has much bonding points and bonding areas with the sintered member 320 compared with other section of the first board member 310a. The inner face 314b of the top of the second projection 313b of the second board member 310b has much bonding points and bonding areas with the sintered member 320 compared with other section of the second board member 310b.

The core 302 of the heat exchanger 300 is separated into the second passages 390 by the recess 312a, 312b and the projection 313a, 313b. The second fluid flows in the core 302 in the separated state. Therefore, the core 302 can be produced by using thinner board member 310a, 310b, compared with a case in which a core has a second passage through which a large amount of second fluid flows. Thus, weight of the heat exchanger 300 can be reduced.

The first board member 310a and the second board member 310b may correspond to a board member. The inner face 314a, 314b may correspond to a first face of the board member.

Other Embodiment

In the first embodiment, the fin 140 is connected to a face of the bottom 113 of the board member 110 opposite from the outer surface 114. However, the fin 140 may be eliminated. Alternatively, as shown in FIG. 11, a board member 410 may have a rib 440 protruding from the bottom 113 in a direction opposite from the recess direction of the recess 112. FIG. 11 is a top plan view illustrating the board member 410 according to other embodiment. The recess 112 of FIG. 11 is recessed in a perpendicular direction from the drawing of FIG. 11.

An approximately center part of the board member 410 has a communication part 417. The communication part 417, has an opening, and protrudes from the bottom 113 in the direction opposite from the recess direction of the recess 112. The rib 440 linearly, extends from the communication part 115, 116 to the communication part 417. The communication part 417 and the rib 440 protrude from the bottom 113 so as to have a protrusion height corresponding to the connecting portion 111.

When the pair of the board members 410 are layered in the contact state, the communication parts 417 are contact with each other, and the ribs 440 are contact with each other. Further, the communication parts 417 are brazed with each other, and the ribs 440 are brazed with each other, when the connecting portions 111 are brazed.

Therefore, first fluid can flow inside of the communication part 417, and a flow of second fluid can be separated by the rib 440. Further, due to the communication part 417 and the rib 440, an expansion deformation of the second passage 190 generated by a pressure difference between the first passage 180 and the second passage 190 can be reduced.

In the first embodiment, the fin 140 is connected to a face of the bottom 113 of the board member 110 opposite from the outer surface 114. However, the fin 140 may be eliminated. Alternatively, as shown in FIGS. 12 and 13, a board member 510 may have a rib 540 protruding from the bottom 113 in a direction opposite from the recess direction of the recess 112.

FIG. 12 is a top plan view illustrating the board member 510 according to other embodiment. FIG. 13 is a cross-sectional view illustrating an adsorption module 503 according to other embodiment. The recess 112 of FIG. 12 is recessed in a perpendicular direction from the drawing of FIG. 12.

Plural ribs 540 are arranged between the communication parts 115, 116. The rib 540 has a protrusion height corresponding to that of the connecting portion 111. The adsorption module 503 is defined by layering a pair of the board members 510 in a state that the connecting portions 111 are contact with each other. At this time, the ribs 540 are contact with each other, and brazed with each other when the connecting portions 111 are brazed with each other.

Therefore, due to the rib 540, second fluid can flow in a meandering state. Further, due to the rib 540, an expansion deformation of the second passage 190 generated by a pressure difference between the first passage 180 and the second passage 190 can be reduced.

As shown in the module 503 of FIG. 13, an outer surface 514 of the board member 510 repeatedly has a recess and a projection. A sintered member 520 is arranged to correspond to the shape of the outer surface 514 repeatedly having the recess and the projection.

As shown in an adsorption module 603 of FIG. 14, an outer surface 514 of the board member 510 repeatedly has a recess and a projection. A sintered member 620 is arranged on the outer surface 514, and a thickness of the sintered member 620 is varied so as to form a flat plane. FIG. 14 is a top plan view illustrating the adsorption module 603 according to other embodiment.

In the second embodiment, the container 210a, 210b has the rib 240a, 240b. However, the rib 240a, 240b may be eliminated, as shown in a heat exchanger 700 of FIG. 15. FIG. 15 is a cross-sectional view illustrating the heat exchanger 700 according to other embodiment.

The heat exchanger 700 is defined by layering containers 710a, 710b not having the rib 240a, 240b. Therefore, a first, bottom 713a of the first container 710a has a flat end face 714a. A second bottom 713b of the second container 710b has a flat end face 714b. A sintered member 720 is arranged between the flat end faces 714a, 714b. Therefore, a space of the recess 221 of the second embodiment can be filled with the sintered member 720.

An adsorption module 703 is defined by layering the containers 710a, 710b in a state that the end face 714a, 714b is located outside of the module 703. A fin 740 is arranged between the modules 703. The fin 740 is brazed to the bottom 713a, 713b of the container 710a, 710b. Therefore, an expansion deformation of the second passage 290 generated by a pressure difference between the first passage 280 and the second passage 290 can be reduced.

In the third embodiment, the left-and-right width of the bottom of the recess 312a of the first board member 310a is not limited to be larger than that of the top of the projection 313a. The left-and-right width of the bottom of the recess 312b of the second board member 310b is not limited to be smaller than that of, the top of the projection 313b.

Alternatively, as shown in FIG. 16, a core 802 may be defined by layering modules 803, and the module 803 is defined by brazing board members 810a, 810b. FIG. 16 is an enlarged cross-sectional view illustrating the core 802 according to other embodiment.

A left-and-right width is set to be the same among recesses 812a, 812b and projection 813a, 813b. A left-and-right dimension of the recess 812a, 812b is increased as the recess 812a, 812b extends toward the recess direction. A left-and-right dimension of the projection 813a, 813b is increased as the projection 813a, 813b extends toward the projection direction.

A sintered member 820 is arranged on an inner base of the recess 812a of the first board member 810a, and is arranged on an inner top of the projection 813b of the second board member 810b. A communication passage 881 corresponding to a first passage 880 is defined on an open side of the recess 812a of the first board member 810a, and on an open side of the projection 813b of the second board member 810b.

A second passage 890 is defined between an inner face of the projection 813a of the first board member 810a and a top face of the projection 813b of the second board member 810b. All outer periphery of the second passage 890 is sealed in a cross-section perpendicular to a flowing direction of second fluid.

The second passage 890 is further defined between an inner face of the recess 812b of the second board member 810b and a bottom face of the recess 812a of the first board member 810a. All outer periphery of the second passage 890 is sealed in a cross-section perpendicular to the flowing direction of the second fluid.

As shown in FIG. 17, a core 902 may be defined by layering and brazing only the first board members 810a. FIG. 17 is an enlarged cross-sectional view illustrating the core 902 according to other embodiment. A heat exchanger having the core 902 can be constructed by only the board member 810a.

In the third embodiment, the heat exchanger 300 is not limited to have the first board member 310a and the second board member 310b. Alternatively, a heat exchanger may be defined by alternately layering a first board member and a reversed first board member. At this time, a connecting portion of the board member extends in both sides of the layering direction. In this case, the heat exchanger can be constructed without the second board member 310b.

The second fluid is not limited to the coolant to cool the internal combustion engine. The second fluid may be other fluid capable to be a heat source.

The board member 110 of the first embodiment is not limited to have the circular shape. Alternatively, the board member 110 may have a rectangular shape.

The board member 110, 310 and the container 210 are not limited to be made of copper. Alternatively, the board member 110, 310 and the container 210 may be made of other heat transmittable material.

The adsorbent is not limited to silica gel. Alternatively, the adsorbent may be made of zeolite.

The communication passage 181, 281, 381 of the first passage 180, 280, 380 may be filled with a sintered member. In this case, first fluid flows through a clearance between the sintered members.

The tubes 150, 160, 170, 250, 260, 270 are not limited to extend in the same direction. Alternatively, the tubes 150, 160, 170, 250, 260, 270 may extend in directions different from each other.

Such changes and modifications are to be understood as being within the scope of the present invention as defined by the appended claims.

Claims

1. A heat exchanger comprising:

a plurality of metal board members layered with each other so as to define a core, a first passage and a second passage being alternately defined between the layered board members, a first fluid passing through the first passage, a second fluid passing through the second passage, the second fluid having a pressure higher than that of the first fluid; and

a sintered member made of a sintered mixture of metal powder and adsorbent, the sintered member adsorbing or desorbing the first fluid, wherein

the board member has a first face defining the first passage and a second face defining the second passage,

the sintered member is layered on the first face of the board member,

the sintered member is pressurized on the first face of the board member in a direction of layering the board members, and

all outer periphery of the second passage is sealed.

2. The heat exchanger according to claim 1, wherein

the board member has a connecting portion around an outer periphery of the second face, and

the connecting portions of the board members are connected with each other when the board members oppose to each other through the second passage.

3. The heat exchanger according to claim 2, wherein

the board member has a recess located on an inner side of the connecting portion,

the recess has an outer face corresponding to the first face of the board member,

the board members opposing to each other define an adsorption module when the connecting portions are connected with each other,

the second passage is defined by an inside of the adsorption module,

the adsorption module is one of a plurality of adsorption modules, and

the plurality of adsorption modules is layered with each other.

4. The heat exchanger according to claim 3, wherein

the sintered member is arranged on the outer face of the recess of the board member,

the adsorption modules located adjacent to each other define a communication passage between the sintered members, and

the first fluid flows through the communication passage.

5. The heat exchanger according to claim 3, wherein

the adsorption module includes a fin located inside of the second passage.

6. The heat exchanger according to claim 1, wherein

the board member has a first container having a first base, an inner face of the first base corresponding to the first face of the board member, and a second container having a second base, an outer face of the second base corresponding to the first face of the board member,

the first container has a first connecting portion extending from all outer periphery of the first base toward a first end of the layering direction,

the second container has a second connecting portion extending from all outer periphery of the second base toward the first end of the layering direction,

the first connecting portion and the second connecting portion are connected with each other in a state that the first connecting portion and the second connecting portion are contact with each other, and

the first container and the second container seal all outer periphery of the second passage in a cross-section perpendicular to a flowing direction of the second fluid.

7. The heat exchanger according to claim 6, wherein

the first container and the second container define an adsorption module having the second passage when the first connecting portion and the second connecting portion are contact with each other,

the adsorption module is one of a plurality of adsorption modules,

the plurality of adsorption modules is layered so as to define the core, and

the sintered member is located between the layered adsorption modules.

8. The heat exchanger according to claim 7, wherein

the first base of the first container has a first rib protruding outward from the first face,

the second base of the second container has a second rib protruding outward from the first face, and

the first rib and the second rib are contact with each other when the plurality of adsorption modules is layered.

9. The heat exchanger according to claim 8, wherein

the sintered member has a groove-shaped communication passage, and

the first fluid flows through the communication passage.

10. The heat exchanger according to claim 9, wherein

the communication passage has a shape to surround all periphery of the first rib and the second rib.

11. The heat exchanger according to claim 1, wherein

the board member alternately has a recess and a projection, the recess being recessed in the layering direction, the projection being projected in the layering direction,

the layered board members are connected with each other through a contact between a top face of the projection of one of the board members and a bottom face of the recess of the other of the board members, and

all outer periphery of the second passage is sealed in a cross-section perpendicular to a flowing direction of the second fluid.