JP2005055067A - Heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat exchanger for performing heat exchange by boiling refrigerant and evaporating a part of the refrigerant and capable of realizing excellent heat exchange efficiency. <P>SOLUTION: A refrigerant flow passage 3 in which the refrigerant flows in a perpendicular direction to an input direction of heat transferred from a heat source 4 is provided and at least a part of the refrigerant is evaporated in the refrigerant flow passage 3 by heat exchange. The refrigerant flow passage 3 is equipped with a main passage 13 and a recessed part 14 which is formed at a heat source 4 side of the main passage 13 along its longitudinal direction and is narrower than the main passage 13. The recessed part 14 is formed so that air bubble generated by evaporation can be discharged to the main passage 13 when at least a part of the refrigerant is evaporated in the recessed part 14 by heat exchange. Width w<SB>1</SB>of the recessed part 14 is 0.1 to 3 mm, favorably, 0.1 to 1 mm. When the width w<SB>1</SB>of the recessed part 14 is 0.1 to 1 mm, depth d<SB>1</SB>of the recessed part 14 is 1/5 to 1/2 of the width w<SB>1</SB>. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cross flow type heat exchanger including a refrigerant flow path in which a refrigerant flows in a direction perpendicular to an input direction of heat transmitted from a heat source.

  In order to cool a heat source, a cross flow type heat exchanger including a refrigerant flow path in which a refrigerant flows in a direction perpendicular to an input direction of heat transmitted from the heat source is used. Conventionally, in the heat exchanger, the liquid refrigerant cools the heat source by taking sensible heat, and by increasing the surface area of the refrigerant flow path by making the cross-sectional shape of the refrigerant flow path uneven, What improved heat exchange efficiency is known (for example, refer to patent documents 1 and 2).

  In recent years, in the heat exchanger, it has been studied to cool the heat source by using latent heat taken when the refrigerant is boiled and a part of the refrigerant is vaporized. In general, since the latent heat per unit mass of the refrigerant is larger than the sensible heat, it is considered that the heat exchange efficiency can be greatly improved by vaporizing a part of the refrigerant.

  In the heat exchanger for boiling the refrigerant, the refrigerant flow path is narrowed in order to increase the heat flux (amount of heat flowing per unit area).

However, if the refrigerant flow path is narrowed, the volume of bubbles generated by the boiling of the refrigerant increases as the heat flux increases, and the bubbles are difficult to move in the narrow flow path. As a result, the heat transfer surface of the refrigerant flow path is covered with the bubbles, and heat transfer to the liquid refrigerant is hindered, resulting in a reduction in heat exchange efficiency.
JP 2000-18867 A JP 2000-74587 A

  The present invention provides a heat exchanger that eliminates such inconvenience and performs heat exchange by boiling a refrigerant and evaporating a part of the refrigerant, thereby obtaining excellent heat exchange efficiency. The purpose is to do.

  In order to achieve such an object, the heat exchanger of the present invention includes a refrigerant flow path in which a refrigerant flows in a direction perpendicular to an input direction of heat transmitted from a heat source, and at least the refrigerant in the refrigerant flow path. A cross flow type heat exchanger partially vaporized by heat exchange, wherein the refrigerant flow path is formed along the length direction of the main flow path on the heat source side of the main flow path A recess having a narrower width, and the recess has a shape capable of releasing bubbles generated by the vaporization into the main channel when at least a part of the refrigerant is evaporated in the recess by heat exchange. And

In the heat exchanger according to the present invention, the refrigerant flowing through the refrigerant flow path is heated by the heat input from the heat source to boil, and is cooled by latent heat taken away when a part of the refrigerant is vaporized. .
The vaporized refrigerant forms bubbles. At this time, the refrigerant flow path is formed with a recess having a narrower width than the main flow path along the length direction of the main flow path on the heat source side of the main flow path. Yes. Therefore, the bubbles are first formed in the recess, and when the diameter increases as they grow, the bubbles are discharged from the recess to the main channel.

  As a result, the bubbles are less likely to stay in the recess close to the heat source, and the liquid refrigerant can easily flow through the recess. Therefore, according to the heat exchanger of the present invention, heat exchange can be performed by the liquid refrigerant flowing through the recess, and heat transfer is not hindered by bubbles generated by vaporization of the refrigerant. Heat exchange efficiency can be obtained.

  The concave portion preferably has a width of 0.1 to 3 mm, and more preferably has a width of 0.1 to 1 mm, so that the bubbles generated therein can be discharged into the main flow path. Is preferred. If the width of the recess is less than 0.1 mm, it is difficult to produce, and if it exceeds 2 mm, the bubbles are difficult to be discharged into the main flow path, and sufficient heat exchange efficiency may not be obtained.

  Moreover, when the said recessed part is equipped with the width | variety of 0.1-1 mm, in order to make it easy to discharge | release the said bubble to the said main flow path, it is equipped with the depth of 1 / 5-1 / 2 of this width | variety. Preferably it is. If the depth of the recess is less than 1/5 of the width, the shape of the recess may not be clear, and the effect of generating bubbles inside the recess may not be sufficiently obtained. In addition, when the depth of the concave portion exceeds 1/2 of the width, the bubbles are difficult to be released into the main flow path, and sufficient heat exchange efficiency may not be obtained.

  Next, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. 1 is an explanatory cross-sectional view showing the configuration of the heat exchanger of the present embodiment, FIG. 2 is a plan view of the heat exchanger shown in FIG. 1, FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2, and FIG. It is explanatory sectional drawing which shows the assembly method of the heat exchanger shown in FIG. FIG. 5 is a graph showing the performance of the heat exchanger shown in FIG.

  As shown in FIGS. 1 and 2, the heat exchanger 1 of this embodiment includes an aluminum heat exchanger body 2 and a refrigerant flow path 3 formed in the heat exchanger body 2. A ceramic heater 4 is stacked as a heat source on one surface of the heat exchanger body 2, and a thermocouple 5 for temperature measurement is further stacked on the ceramic heater 4.

  The heat exchanger body 2, the ceramic heater 4, and the thermocouple 5 are sandwiched between two silicon rubber sheets 6a, 6b, 7a, and 7b from both outsides, and from the outside of the silicon rubber sheets 6a, 6b, 7a, and 7b. It is sandwiched between stainless plates 8a and 8b. The heat exchanger body 2, the ceramic heater 4, and the thermocouple 5 are bolted by a bolt 9 that penetrates through the stainless steel plates 8a and 8b and a nut 10 that is screwed to the bolt 9, and the whole is uniformly crimped. .

  In the heat exchanger 1, after the liquid refrigerant is supplied from the flow path inlet 3 a, it is distributed to each refrigerant flow path 3 by the distributor 11, and heat and heat input from the ceramic heater 4 in the refrigerant flow path 3. It is heated and boiled by exchanging, and a part of the refrigerant is vaporized. As a result, the heat exchanger 1 can cool the ceramic heater 4 by latent heat when the liquid refrigerant is vaporized. The boiled liquid refrigerant and the vaporized refrigerant vapor are discharged from the flow path outlet 3b through the collecting portion 12.

As shown in FIG. 3, the refrigerant flow path 3 includes a main flow path 13 having a quadrangular cross section, and a concave section 14 having a quadrangular cross section formed along the length direction of the main flow path 13 on the ceramic heater 4 side of the main flow path 13. Formed from. Here, the width w ₁ of the recess 14 is narrower than the width w ₂ of the main flow path 13 and is in the range of 0.1 to 3 mm. Further, the depth d ₁ of the recess 14 is in the range of 1/5 to 2 times the width w ₁ of the recess 14.

  In the heat exchanger 1, since the refrigerant flow path 3 is provided with the concave portion 14 on the ceramic heater 4 side of the main flow path 13, the liquid refrigerant boils and vaporizes in the concave portion 14 to generate bubbles. The bubble grows in the recess 14 and gradually increases in diameter. However, since the recess 14 has the shape, the bubble having a large diameter is pushed out from the recess 14 and discharged into the main flow path 13. As a result, in the heat exchanger 1, the liquid refrigerant can easily flow through the concave portion 14 close to the ceramic heater 4, heat exchange can be performed by the refrigerant, and heat transfer is not hindered by the bubbles. Excellent heat exchange efficiency can be obtained.

The width w _{1 of the} recess 14 is preferably in the range of 0.1 to 3 mm, and more preferably in the range of 0.1 to ₁ mm, in order to facilitate the extrusion of bubbles having a large diameter. Further, when the width w ₁ of the recess 14 is in the range of 0.1 to 1 mm, the depth d ₁ of the concave portion 14, in order to facilitate extrusion bubbles became larger diameter, the width w ₁ of the concave portion 14 It is preferably in the range of 1/5 to 1/2 times.

  Next, examples and comparative examples of the present invention are shown.

In Examples 1 to 16 and Comparative Examples 1 to 11, first, as shown in FIG. 4, a plurality of grooves 15 opened on the opposite side to the ceramic heater 4 are formed by cutting on a 24 mm × 20 mm aluminum (A5052) plate. The heat source side member 16 and the counter heat source side member 18 in which a plurality of grooves 17 opened to the ceramic heater 4 side were cut by cutting on a 24 mm × 20 mm aluminum (A5052) plate were prepared. The heat source side member 16 is formed with n grooves 15 each having a length of 12 mm, a width w ₁ mm, and a depth d ₁ mm at an interval of G ₁ mm. On the other hand, m grooves 17 having a length of 12 mm, a width w ₂ mm, and a depth d ₂ mm are formed in the counter heat source side member 18 at intervals of G ₂ mm.

  Table 1 shows the heat source side members 16 (HE-1 to 11) used in Examples 1 to 16 and Comparative Examples 1 to 11, and Table 2 shows the counter heat source side members 18 (Co-1 to 8).

Next, the heat exchanger main body 2 was formed by laminating the heat source side member 16 and the counter heat source side member 18 so that the surfaces where the groove portions 15 and 17 are opened face each other. At this time, the combination of the plural types of heat source side members 16 shown in Tables 1 and 2 and the counter heat source side member 18 is changed so that the recesses 14 are formed by the groove portions 15 and the main flow path 13 is formed by the groove portions 17. Thus, the heat exchanger 1 of Examples 1 to 16 was configured. Further, by changing the combination of the heat source side member 16 and the counter heat source side member 18 so that the widths of the grooves 15 and 17 are equal (w ₁ = w ₂ ), the recess 14 is not formed, and only the main flow path 13 is formed. The heat exchanger 1 of Comparative Examples 1-11 provided with these was comprised.

  Depending on the combination of the heat source side member 16 and the counter heat source side member 18, a plurality of recesses 14 may be formed in one main flow path 13. In addition, the heat source side member 16 and the counter heat source side member 18 have a 2 mm × 14 mm recess (not shown) formed by cutting to form the distribution portion 11 and the gathering portion 12 at the ends of the groove portions 15 and 17, respectively. ing.

  Next, while supplying 75 W of electric power to the ceramic heater 4, the temperature of the ceramic heater 4 when supplying 90 ° C. water at a flow rate of 3 g / min from the flow path inlet 3 a of FIGS. The performance of each heat exchanger 1 was compared by measuring. The temperature of the ceramic heater 4 was measured in a state where the entire apparatus shown in FIG. 1 was covered with an armor flex tube and insulated from the outside. The results are shown in Table 3.

  From Table 3, according to the heat exchanger 1 of Examples 1-16 which provided the recessed part 14 in the main flow path 13, the temperature of the ceramic heater 4 is 145.4-157.8 degreeC, there is no recessed part 14, and the main flow path 13 As compared with 167.7 to 168.2 ° C. of Comparative Examples 1 to 11 including only, it is clear that a remarkably excellent heat exchange rate can be obtained.

In addition, Examples ₁ , 4 to 7, 14 in which the width w _{1 of the} recess 14 is in the range of 0.1 to ₁ mm and the depth d ₁ is in the range of 1/5 to 1/2 times the width w _1. According to the heat exchanger 1, the temperature of the ceramic heater 4 is 145.4 to 145.7 ° C., and it is clear that a further excellent heat exchange rate can be obtained.

The heat exchanger 1 was formed using HE-1 as the heat source side member 16 and Co-3 as the counter heat source side member 18. In this heat exchanger 1, the width w ₂ of the main flow path 13 is 0.5 mm and the depth d _{2 is} 0.3 mm, the width w _{1 of the} recess 14 is 0.1 mm, and the depth d _{1 is} 0.05 mm. It has become.

  Next, while the electric power supplied to the ceramic heater 4 is varied in the range of 8 to 40 W, the 90 ° C. water is supplied at a flow rate of 3 g / min from the flow path inlet 3a of FIGS. The temperature was measured with a thermocouple 5. The temperature of the ceramic heater 4 was measured in a state where the entire apparatus shown in FIG. 1 was covered with an armor flex tube and insulated from the outside. The results are shown in Table 4 and FIG.

Comparative Example 12

The heat exchanger 1 was formed using HE-1 as the heat source side member 16 and Co-2 as the counter heat source side member 18. In this heat exchanger 1, the width w ₂ of the main flow path 13 is 0.1 mm, the depth d _{2 is} 0.15 mm, and no recess 14 is provided.

  Next, while the electric power supplied to the ceramic heater 4 is varied in the range of 8 to 40 W, the 90 ° C. water is supplied at a flow rate of 3 g / min from the flow path inlet 3a of FIGS. The temperature was measured with a thermocouple 5. The temperature of the ceramic heater 4 was measured in a state where the entire apparatus shown in FIG. 1 was covered with an armor flex tube and insulated from the outside. The results are shown in Table 4 and FIG.

  From Table 4 and FIG. 5, according to the heat exchanger 1 of Example 17 which provided the recessed part 14 in the main flow path 13, in the case of each supply electric power, the temperature of the ceramic heater 4 does not have the recessed part 14, but only the main flow path 13 is used. It is clear that the heat exchanger 1 is lower than the heat exchanger 1 of the comparative example 12 that is provided, and the temperature of the ceramic heater 4 is less increased with respect to the increase in power supply, so that a remarkably excellent heat exchange rate can be obtained.

  In Examples 18 to 21 and Comparative Examples 13 to 16, when the heat exchanger 1 was formed by changing the combination of the plurality of types of heat source side members 16 and the counter heat source side members 18 shown in Tables 1 and 2, the heat source The positions of the side member 16 and the counter heat source side member 18 are opposite to those in FIG. 4, and the heat source side member 16 is disposed below and the counter heat source side member 18 is disposed above. The ceramic heater 4 and the thermocouple 5 were disposed on the lower surface of the heat source side member 16.

At this time, the recessed part 14 was formed by the groove part 15, and the main flow path 13 was formed by the groove part 17, and the heat exchanger 1 of Examples 18-21 was comprised. Further, a comparative example in which the recesses 14 are not formed and only the main flow path 13 is provided so that the widths of the grooves 15 and 17 are equal (w ₁ = w ₂ ) between the heat source side member 16 and the counter heat source side member 18. 13 to 16 heat exchangers 1 were configured.

  Next, while supplying 75 W of electric power to the ceramic heater 4, the temperature of the ceramic heater 4 when supplying 90 ° C. water at a flow rate of 3 g / min from the flow path inlet 3 a of FIGS. The performance of each heat exchanger 1 was compared by measuring. The temperature of the ceramic heater 4 was measured in a state where the entire apparatus shown in FIG. 1 was covered with an armor flex tube and insulated from the outside. The results are shown in Table 5.

  From Table 5, according to the heat exchanger 1 of Examples 18-21 which provided the recessed part 14 in the main flow path 13, the temperature of the ceramic heater 4 is 144.9-145.2 degreeC, there is no recessed part 14, and the main flow path 13 As compared with 167.9 to 168.2 ° C. of Comparative Examples 13 to 16 including only, it is clear that a remarkably excellent heat exchange rate can be obtained.

  Further, from Table 5, when the ceramic heater 4 is on the lower side of the heat exchanger 1, the concave portion 14 is provided on the ceramic heater 4 side of the main flow path 13 as in the case of being on the upper side of the heat exchanger 1. It is clear that an excellent heat exchange rate can be obtained.

Explanatory sectional drawing which shows the example of 1 structure of the heat exchanger of this invention. The top view of the heat exchanger shown in FIG. III-III sectional view taken on the line of FIG. Explanatory sectional drawing which shows the assembly method of the heat exchanger shown in FIG. It is a graph which shows the performance of the heat exchanger shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Heat exchanger, 2 ... Heat exchanger main body, 3 ... Refrigerant flow path, 4 ... Heat source, 13 ... Main flow path, 14 ... Recessed part.

Claims (4)

This is a cross-flow type heat exchanger that includes a refrigerant flow path in which a refrigerant flows in a direction perpendicular to an input direction of heat transmitted from a heat source, and at least a part of the refrigerant is vaporized by heat exchange in the refrigerant flow path. And
The refrigerant flow path includes a main flow path, and a concave portion narrower than the main flow path formed along the length direction of the main flow path on the heat source side of the main flow path. A heat exchanger comprising a shape capable of releasing bubbles generated by vaporization into the main flow path when at least a part thereof is vaporized in the recess.   The heat exchanger according to claim 1, wherein the recess has a width of 0.1 to 3 mm.   The heat exchanger according to claim 1 or 2, wherein the recess has a width of 0.1 to 1 mm. The heat exchanger according to claim 3, wherein the recess has a depth of 1/5 to 1/2 of the width.

Images