JP2013228189A - Heat exchanging member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat exchanging member capable of lowering heat exchanging efficiency so that a temperature of a low-temperature fluid does not excessively increase, when a flow rate of a high-temperature fluid is high in exchanging heat between the high-temperature fluid and the low-temperature fluid, and reducing breakage failure due to thermal shock of a downstream component of the heat exchanging member.SOLUTION: In a honeycomb structure 1 configuring a heat exchanging member 10, a cell structural section 3a has a cell structure having two or more different aperture ratios. A larger value of S/Sor S/Sis 1.05-2.0, when the total opening area of each region is S, Swhen a sectional area is divided into two regions X, Y on halves. Further, a heat transfer reducing section may be disposed on the honeycomb structure, or a projecting section or a recessed section may be formed on an end face of the honeycomb structure. Furthermore, the honeycomb structure may be coated with a coating member, a stirring plate may be disposed in the coating member, and the coating member may be provided with a small diameter section or a large diameter section.

Description

  The present invention relates to a heat exchange member using a honeycomb structure that can perform heat exchange between a first fluid and a second fluid.

  By exchanging heat from a high temperature fluid to a low temperature fluid, heat can be effectively utilized. For example, there is a heat recovery technique for recovering heat from a high-temperature gas such as combustion exhaust gas from an engine. As the gas / liquid heat exchanger, a tube-type heat exchanger with fins such as an automobile radiator or an air conditioner outdoor unit is generally used. However, in order to recover heat from a gas such as automobile exhaust gas, a general metal heat exchanger has poor heat resistance and is difficult to use at high temperatures. Therefore, a heat-resistant metal or ceramic material having heat resistance, heat shock, corrosion resistance, or the like is suitable. However, refractory metals have problems such as high price and difficulty in processing, high density and heavyness, and low heat conduction.

  Therefore, a heat recovery technique using a ceramic material has been developed. For example, there is a technique for performing heat exchange with a heat exchange member using a ceramic body. In this case, heat exchange is performed by circulating a first fluid (for example, exhaust gas) inside the cylindrical ceramic body and circulating a second fluid (for example, cooling water) outside.

  However, when there is much exhaust gas circulated inside the ceramic body, the temperature of the cooling water circulated to the outside rises, which may cause overheating. Therefore, in Patent Document 1, a valve is provided in the exhaust flow path so that the exhaust does not pass through the exhaust heat recovery device when the exhaust amount is large.

JP 2007-315370 A

  However, the technique of Patent Document 1 has a problem that the structure of the apparatus becomes complicated and the cost increases because an exhaust switching valve or the like is added to the exhaust system.

  An object of the present invention is to provide a heat exchange member that lowers the heat exchange efficiency so that the temperature of the low temperature fluid does not rise excessively when the flow rate of the high temperature fluid is large when heat exchange is performed between the high temperature fluid and the low temperature fluid. There is to do.

  Moreover, it is providing the heat exchange member which can reduce the damage by the thermal shock of the components downstream of a heat exchange member.

  The inventors of the present invention have increased the temperature of the low-temperature fluid by configuring the honeycomb structure constituting the heat exchange member to have a cell structure having two different opening ratios or providing a heat transfer reduction unit. It has been found that the above problem of reducing the heat exchange efficiency so as not to be too much can be solved. In addition, a projecting portion or a recessed portion is provided on the end face of the honeycomb structure, the honeycomb structure is covered with a covering member, and a stirring plate is provided in the covering member, or the covering member is provided with a small diameter portion or a large diameter portion. Thus, it has been found that the above-described problem of reducing damage due to thermal shock of components downstream of the heat exchange member can be solved. That is, according to the present invention, the following heat exchange member is provided.

[1] It has a plurality of cells that penetrate from one end to the other end to serve as a flow path for the first fluid, and a partition mainly composed of ceramics that partitions the plurality of cells. The formed cell structure part and the outer periphery of the cell structure part, mainly composed of ceramics, without mixing the first fluid and the second fluid flowing on the outer periphery side of the cell structure part, A honeycomb structure including an outer peripheral wall through which heat is transferred between the first fluid and the second fluid, and the cell structure section includes two or more cross sections perpendicular to the axial direction. When cell structures having different aperture ratios and divided into two regions X and Y each having a cross-sectional area of ½, the cell structure having the largest area in each region X and Y is defined as cell structure A and cell As a structure B, the total opening area of each of the regions X and Y is S _X and S _Y. Then, the larger value of S _X / S _Y or S _Y / S _X is 1.05 to 2.0, and the flow rate before the first fluid flowing into the cell structure portion changes. When the flow rates V ₁ and V ₂ have the same fluid temperature and V ₂ / V ₁ ≧ 2, the heat exchange efficiencies of the flow rates V ₁ and V ₂ are λ ₁ and λ ₂ , respectively. If the cell structure part is composed of only the cell structure A, the heat exchange efficiencies of V ₁ and V ₂ are respectively λ _1A and λ _2A, and the cell structure part is composed of only the cell structure B. When the heat exchange efficiencies of V ₁ and V ₂ are λ _1B and λ _2B respectively, λ ₁ / λ ₂ is larger than the larger value of λ _1A / λ _2A and λ _1B / λ _2B Heat exchange member.

[2] The heat exchange member according to [1], wherein the honeycomb structure has a partition wall thickness of 0.15 to 0.64 mm.

[3] The heat exchange member according to [1] or [2], wherein the honeycomb structure has a cell density of 4.7 to 62 cells / cm ² .

[4] The heat exchange member according to any one of [1] to [3], wherein the honeycomb structure has an opening ratio of the cells of 40% to 80%.

[5] A honeycomb structure mainly composed of ceramics having a cylindrical outer peripheral wall and partition walls that partition and form a plurality of cells serving as a flow path for the first fluid, and the flow through the inside of the honeycomb structure The honeycomb structure is capable of heat exchange between the first flow path and the second fluid without mixing the first fluid and the second fluid flowing outside the honeycomb structure. A coating member to be coated, a heat transfer reduction portion that reduces heat transfer between the honeycomb structure and the coating member is provided in a part of the range, and the first fluid that circulates through the cells; Heat exchange is performed between the first fluid and the second fluid via the outer peripheral wall of the honeycomb structure and the covering member in a state where the second fluid flowing outside the covering member is not mixed. Heat exchange member.

[6] The heat transfer reduction portion is configured such that the outer peripheral wall, which is an outer peripheral portion of the honeycomb structure, or the outer peripheral wall and the partition wall are 0.3 mm or more with respect to an average diameter of the honeycomb structure. The heat exchange member according to [5], wherein the heat exchange member is a constricted portion that is constricted by 10% or more with respect to the total surface area.

[7] The heat transfer reduction portion is formed of a heat insulating material provided in a range of 10% or more with respect to the total surface area of the outer peripheral portion of the honeycomb structure between the honeycomb structure and the covering member. The heat exchange member according to [5].

[8] A honeycomb structure mainly composed of ceramics having a cylindrical outer peripheral wall and partition walls that define and form a plurality of cells serving as flow paths for the first fluid, and the flow through the inside of the honeycomb structure The honeycomb structure is capable of heat exchange between the first flow path and the second fluid without mixing the first fluid and the second fluid flowing outside the honeycomb structure. A coating member for coating, further comprising stirring means for stirring the flow of the first fluid, the first fluid flowing through the cell, and the second fluid flowing outside the coating member. A heat exchange member that exchanges heat between the first fluid and the second fluid through the outer peripheral wall of the honeycomb structure and the covering member in a state where the first fluid and the second fluid are not mixed.

[9] The above [8], wherein as the stirring means, at least one end face in the axial direction of the honeycomb structure is formed with one or more convex portions or concave portions having a length in the axial direction of 1 mm or more. Heat exchange member.

[10] The stirring means is a stirring plate for stirring the first fluid provided in the covering member alongside the honeycomb structure in the axial direction of the honeycomb structure. 8].

[11] The heat exchanging member according to [8], wherein the stirring means is a covering member having one or more small-diameter portions constricted in a portion not covering the honeycomb structure or swelled large-diameter portions.

In the heat exchange member of the present invention, the larger value of S _X / S _Y or S _Y / S _X of the ratio of the opening areas of the regions X and Y is 1.05 to 2.0, As the gas flow rate increases, the heat exchange efficiency decreases. That is, even if the flow rate of the first fluid is increased, the heat exchange member is less likely to cause overheating.

  The heat exchange member can reduce heat transfer between the honeycomb structure and the covering member that covers the honeycomb structure by providing the heat transfer reduction portion. Therefore, such a heat exchange member hardly generates overheating even if the flow rate of the first fluid increases.

  Since the heat exchange member has a convex portion or a concave portion on the end face in the axial direction of the honeycomb structure, it is possible to reduce damage due to thermal shock of components downstream of the heat exchange member.

  The heat exchange member can reduce damage due to thermal shock of components downstream of the heat exchange member by covering the honeycomb structure with the coating member and providing the stirring member in the coating member.

  In the heat exchange member, the honeycomb structure is covered with a covering member, and the covering member is provided with a small-diameter portion or a large-diameter portion, whereby damage due to thermal shock of components downstream of the heat exchange member can be reduced. .

It is a schematic diagram which shows Embodiment 1 of the heat exchange member of this invention. It is a schematic diagram which shows the case where an area | region is divided | segmented by a circle. It is a schematic diagram for demonstrating the area | regions X and Y. FIG. It is a schematic diagram which shows the case where an area | region is divided | segmented by a straight line. It is a figure for demonstrating the change of the heat exchange efficiency with respect to a flow volume. It is a mimetic diagram showing an embodiment of a heat exchange member whose diameter of a honeycomb structure is more than twice the length of an axial direction. It is a schematic diagram which shows Embodiment 2 of the honeycomb structure which comprises the heat exchange member of this invention. It is a schematic diagram which shows Embodiment 3 of the honeycomb structure which comprises the heat exchange member of this invention. Fig. 7 is a schematic diagram showing a fourth embodiment of a honeycomb structure constituting the heat exchange member of the present invention. Fig. 6 is a schematic diagram showing a fifth embodiment of a honeycomb structure constituting the heat exchange member of the present invention. It is a perspective view of the heat exchanger containing a heat exchange member. It is a schematic diagram which shows Embodiment 1 in which the heat-transfer reduction part was provided as a constriction part. It is a schematic diagram which shows Embodiment 2 with which the heat-transfer reduction part was provided as a constriction part. It is a schematic diagram which shows Embodiment 3 with which the heat-transfer reduction part was provided as a constriction part. It is a schematic diagram which shows Embodiment 4 with which the heat-transfer reduction part was provided as a constriction part. It is an enlarged view around a constricted part, and is a schematic diagram showing an embodiment in which a constricted part is formed on an outer peripheral wall. It is an enlarged view of the periphery of a constricted part, and is a schematic diagram showing an embodiment in which the constricted part is formed by an outer peripheral wall and a partition wall. It is a schematic diagram which shows embodiment in which the heat insulation reduction part was formed with the heat insulating material. It is a schematic diagram which shows the heat exchange member which has a convex part in the end surface of a honeycomb structure. It is a schematic diagram which shows the heat exchange member which has a recessed part in the end surface of a honeycomb structure. It is a schematic diagram which shows embodiment provided with the stirring plate for stirring a 1st fluid in a coating | coated member. It is a schematic diagram which shows Embodiment 1 of a stirring plate. It is a schematic diagram which shows Embodiment 2 of a stirring plate. It is a schematic diagram which shows Embodiment 3 of a stirring plate. It is a schematic diagram which shows embodiment of the heat exchange member provided with the coating | coated member which has a small diameter part and a large diameter part.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the following embodiments, and changes, modifications, and improvements can be added without departing from the scope of the invention.

1. Reduction of heat exchange efficiency due to cell structure FIG. 1 shows a first embodiment of a heat exchange member 10 of the present invention. The heat exchange member 10 of the present invention includes a honeycomb structure 1 including a cell structure portion 3a and an outer peripheral wall 7. The cell structure portion 3a includes a plurality of cells 3 that pass from one end portion to the other end portion and serve as a flow path for the first fluid, and a partition wall 4 that is mainly composed of ceramics that partitions and forms the plurality of cells 3. Are formed. The outer peripheral wall 7 is provided on the outer periphery of the cell structure portion 3a, is made of ceramics as a main component, and does not mix the first fluid and the second fluid flowing on the outer periphery side of the cell structure portion 3a. And the transfer of heat between the second fluid and the second fluid.

In the honeycomb structure 1, the cell structure 3a has a cell structure with two or more different aperture ratios in a cross section perpendicular to the axial direction (FIG. 1 is an example having cell structures with two different aperture ratios). ). When divided into two regions X and Y each having a half cross-sectional area, the cell structures having the largest areas in the regions X and Y are referred to as cell structure A and cell structure B, respectively. Further, in the honeycomb structure 1, when the total opening area of each of the regions X and Y is S _X and S _Y , the larger value of S _X / S _Y or S _Y / S _X is 1.05 to 2 .0.

Here, examples of how to divide into two regions X and Y each having a half of the cross-sectional area include a circle (FIG. 2A), a straight line (FIG. 2C), and the like. It is possible. FIG. 2B is a schematic diagram showing the regions X and Y when the regions X and Y are separated at the boundary 9 in the cell structure of FIG. 2A. In the embodiment of FIGS. 2A and 2B, region X includes cell structure A and cell structure B. The region Y is only the cell structure B. When the heat exchange member 10 of the present invention is divided into two regions X and Y and then the ratio value of the total opening areas S _X and S _Y of the respective regions is determined, S _X / S _Y or S _Y / S _X In the dividing method in which the larger value is the largest, the value is 1.05 to 2.0. In the case of the heat exchanging member 10 of FIG. 1, there is a method of dividing FIG. 2A (FIG. 2B) and FIG. 2C (there are other methods of dividing). ). And the value is 1.05-2.0. The heat exchange member 10 of FIG. 1 is an embodiment in which a cell structure with a coarse cell density is formed in a circular shape on the center side, and a cell structure with a dense cell density is formed on the outer peripheral side.

  In the heat exchange member 10, the first fluid flows through each cell 3 of the honeycomb structure 1 without leaking or mixing outside the cell 3. That is, the honeycomb structure 1 is formed so that the first fluid flowing in a certain cell 3 does not leak to the other cells 3 through the partition walls 4. The first fluid flowing through the cells 3 and the second fluid flowing outside the outer peripheral wall 7 of the honeycomb structure 1 are not mixed with each other through the outer peripheral wall 7 of the honeycomb structure 1. Heat exchange between the first fluid and the second fluid.

A change in heat exchange efficiency with respect to a change in the flow rate of the first fluid in the heat exchange member 10 will be described with reference to FIG. The heat exchange member 10 is composed of two cell structures A and B (see FIGS. 2A and 2B), and the larger value of S _X / S _Y or S _Y / S _X is 1.05 to 2.0, the case where the flow rate before the inflow of the first fluid flowing into the cell structure portion 3a changes will be described (note that FIG. 2A is a case of two cell structures, but 3 In the case of having two or more cell structures, the cell structures having the largest areas in each of the regions X and Y are considered as cell structures A and B). If the cell structure portion 3a is composed of only the cell structure A, the heat exchange efficiencies of V ₁ and V ₂ are λ _1A and λ _2A , respectively, and the cell structure portion 3a is composed of only the cell structure B. Assuming that the heat exchange efficiencies of V ₁ and V ₂ are λ _1B and λ _2B , respectively, the heat exchange member 10 of the present embodiment has a certain flow rate V ₁ , V ₂ of V _{2 at the} same fluid temperature. / V ₁ ≧ 2, where the heat exchange efficiencies of the flow rates V ₁ and V ₂ are λ ₁ and λ ₂ , respectively, than the larger value of λ _1A / λ _2A and λ _1B / λ _2B λ ₁ / λ ₂ increases. That is, when the flow rate of the first fluid is small (V ₁ ), the heat exchange efficiency is large (close to λ _1A ), and when the flow rate is large (V ₂ ), the heat exchange efficiency is small (close to λ _1B ). . For this reason, even when the flow rate of the first fluid is increased, the heat exchange member 10 is less likely to generate overheating. The heat exchange member 10 satisfies the above relationship when certain flow rates V ₁ and V ₂ are the same fluid temperature, but the fluid temperature may satisfy the above relationship in the operating temperature range. Particularly preferred.

  Further, in the heat exchange member 10, it is preferable that the covering member 11 is fitted to the outer peripheral surface 7 h of the honeycomb structure 1. If comprised in this way, it can prevent that the 1st fluid which distribute | circulates the inside of the honeycomb structure 1 and the 2nd fluid which distribute | circulates the exterior are mixed. In addition, as the covering member 11, a metal tube 12 is exemplified. Since the metal tube 12 is easily processed, it is easy to install the heat exchange member 10.

  As the metal tube 12 fitted to the outer peripheral surface 7h of the honeycomb structure 1, one having heat resistance and corrosion resistance is preferable. For example, stainless steel, titanium, copper, brass or the like can be used. Since the connecting portion is formed of metal, chemical bonding such as press fitting, shrink fitting, caulking, etc., brazing, welding, etc. can be freely selected according to the application and possessed equipment.

  The honeycomb structure 1 is formed in a cylindrical shape with ceramics, and has a fluid flow path penetrating from one end face 2 in the axial direction to the other end face 2. The honeycomb structure 1 has partition walls 4, and a large number of cells 3 serving as fluid flow paths are partitioned by the partition walls 4. By having the partition walls 4, the heat from the fluid flowing through the inside of the honeycomb structure 1 can be efficiently collected and transmitted to the outside.

  The outer shape of the honeycomb structure 1 is not limited to the cylindrical shape (columnar shape), and the cross section perpendicular to the axial (longitudinal) direction may be elliptical. Further, the outer shape of the honeycomb structure 1 may be prismatic, that is, the cross section perpendicular to the axial (longitudinal) direction may be a quadrangle or other polygons.

  When the outer shape of the honeycomb structure 1 is cylindrical, the diameter of the cross section perpendicular to the axial direction (in the case of non-cylindrical shape, the average distance passing through the center of the cross section) is D, and the length in the axial direction is L It is preferable that the honeycomb structure has D / L = 2 or more. FIG. 4 shows an embodiment of the heat exchange member 10 in which the diameter of the honeycomb structure 1 is twice or more the axial length. If it does in this way, since fluid tends to blow through when the flow rate increases, the heat exchange efficiency when the flow rate of the first fluid increases is unlikely to increase.

  In the heat exchange member 10 of the present invention, the honeycomb structure 1 is mainly composed of ceramics, so that the thermal conductivity of the partition walls 4 and the outer peripheral wall 7 is increased. As a result, the partition walls 4 and the outer peripheral wall 7 are interposed. Heat exchange can be performed efficiently. As used herein, the term “mainly composed of ceramics” means containing 50% by mass or more of ceramics.

  The honeycomb structure 1 is preferably made of ceramics having excellent heat resistance, and considering heat conductivity in particular, it is preferable that SiC (silicon carbide) having high thermal conductivity is a main component. The main component means that 50% by mass or more of the honeycomb structure 1 is silicon carbide.

  However, it is not always necessary that the entire honeycomb structure 1 is made of SiC (silicon carbide), and it is sufficient that SiC (silicon carbide) is contained in the main body. That is, the honeycomb structure 1 is preferably made of ceramics containing SiC (silicon carbide).

  Moreover, even if it is SiC (silicon carbide), in the case of a porous body, a high thermal conductivity cannot be obtained. Therefore, it is preferable to impregnate silicon in the process of manufacturing the honeycomb structure 1 to obtain a dense structure. High heat conductivity can be obtained by using a dense structure. For example, in the case of a porous body of SiC (silicon carbide), it is about 20 W / (m · K), but can be made about 150 W / (m · K) by using a dense body.

As the honeycomb structure 1, Si-impregnated SiC, (Si + Al) -impregnated SiC, metal composite SiC, recrystallized SiC, Si ₃ N ₄ , SiC, or the like can be adopted, but a dense body for obtaining high heat exchange efficiency Si-impregnated SiC or (Si + Al) -impregnated SiC can be used for the structure. Si-impregnated SiC has a structure in which the SiC particle surface is surrounded by solidified metal-silicon melt and SiC is integrally bonded via metal silicon, so that silicon carbide is shielded from an oxygen-containing atmosphere and prevented from oxidation. Is done. Furthermore, SiC has the characteristics of high thermal conductivity and easy heat dissipation, but SiC impregnated with Si is densely formed while exhibiting high thermal conductivity and heat resistance, and has sufficient strength as a heat transfer member. Indicates. That is, the honeycomb structure 1 made of a Si—SiC-based [Si-impregnated SiC, (Si + Al) -impregnated SiC] material has excellent heat resistance, thermal shock resistance, oxidation resistance, and excellent corrosion resistance against acids and alkalis. And high thermal conductivity.

  As the cell shape of the cross section perpendicular to the axial direction of the cells 3 of the honeycomb structure 1, a desired shape may be appropriately selected from circular, elliptical, triangular, quadrangular, hexagonal and other polygons.

The cell density of the honeycomb structure 1 (that is, the number of cells per unit cross-sectional area) is not particularly limited and may be appropriately designed according to the purpose, but is 30 to 400 cells / in 2 (4.7 to 62). Cell / cm ² ) is preferable (note that the honeycomb structure 1 has a cell structure having two or more different aperture ratios, and any cell structure is preferably within the above range. ). When the cell density is 30 cells / square inch or more, the strength of the partition walls 4 and the strength of the honeycomb structure 1 itself and the effective GSA (geometric surface area) can be made sufficient. On the other hand, when the cell density is 400 cells / square inch or less, the pressure loss when the heat medium flows can be reduced.

  The number of cells per honeycomb structure 1 is preferably 1 to 10,000, and particularly preferably 200 to 2,000. If the number of cells is too large, the honeycomb itself becomes large, so the heat conduction distance from the first fluid side to the second fluid side becomes long, the heat conduction loss becomes large, and the heat flux becomes small. Further, when the number of cells is small, the heat transfer area on the first fluid side becomes small, the heat resistance on the first fluid side cannot be lowered, and the heat flux becomes small.

  The thickness (wall thickness) of the partition walls 4 of the cells 3 of the honeycomb structure 1 may be appropriately designed according to the purpose, and is not particularly limited. The wall thickness is preferably 6 to 25 mil (0.15 mm to 0.64 mm), more preferably 8 to 22 mil (note that the honeycomb structure 1 has a cell structure having two or more different opening ratios. However, any cell structure is preferably within the above range.) When the wall thickness is 6 mils or more, the mechanical strength is improved and damage due to impact or thermal stress can be prevented. On the other hand, when the thickness is 25 mil or less, the ratio of the cell volume to the honeycomb structure 1 side increases, so that the pressure loss of the fluid decreases and the heat exchange efficiency can be improved.

The density of the partition walls 4 of the cells 3 of the honeycomb structure 1 is preferably 0.5 to ⁵ g / cm ³ . In the case of 0.5 g / cm ³ or more, the strength of the partition wall 4 is sufficient, and the partition wall 4 can be prevented from being damaged by pressure when the first fluid passes through the flow path. Further, if it is 5 g / cm ³ or less, the honeycomb structure 1 itself does not become too heavy, and the weight can be reduced. By setting the density within the above range, the honeycomb structure 1 can be strengthened. Moreover, the effect which improves heat conductivity is also acquired.

In the honeycomb structure 1, the opening ratio of the cells 3 is preferably 40% to 80%, and more preferably 50% to 75% (note that the honeycomb structure 1 has two or more different opening ratios). It is preferable that any cell structure is within the above range. When the aperture ratio is within this range, the first fluid can be sufficiently circulated, and the heat exchange efficiency can be improved.

  The honeycomb structure 1 preferably has a thermal conductivity of 100 W / (m · K) or more. More preferably, it is 120-300 W / (m * K), More preferably, it is 150-300 W / (m * K). By setting it as this range, heat conductivity becomes favorable and the heat in the honeycomb structure 1 can be efficiently discharged to the outside of the metal tube 12.

  When the first fluid (high temperature side) to be circulated through the heat exchanger 30 (see FIG. 6) using the heat exchange member 10 is exhaust gas, the cells 3 of the honeycomb structure 1 through which the first fluid (high temperature side) passes. It is preferable that a catalyst is supported on the inner wall surface. This is because in addition to the role of exhaust gas purification, reaction heat (exothermic reaction) generated during exhaust gas purification can also be exchanged. Precious metals (platinum, rhodium, palladium, ruthenium, indium, silver and gold), aluminum, nickel, zirconium, titanium, cerium, cobalt, manganese, zinc, copper, tin, iron, niobium, magnesium, lanthanum, samarium, bismuth and It is preferable to contain at least one element selected from the group consisting of barium. These may be metals, oxides, and other compounds.

  The supported amount of the catalyst (catalyst metal + support) supported on the partition walls 4 of the cells 3 of the first fluid circulation part 5 of the honeycomb structure 1 through which the first fluid (high temperature side) passes is 10 to 400 g / It is preferable that it is L, and if it is a noble metal, it is still more preferable that it is 0.1-5 g / L. When the amount of the catalyst (catalyst metal + support) supported is 10 g / L or more, the catalytic action is sufficiently exhibited. On the other hand, when it is 400 g / L or less, the pressure loss does not become too large, and an increase in manufacturing cost can be suppressed.

  Next, another embodiment of the cell structure of the honeycomb structure 1 constituting the heat exchange member 10 will be described. FIG. 5A shows Embodiment 2 of the honeycomb structure 1 constituting the heat exchange member 10. The heat exchange member 10 according to the second embodiment is an embodiment in which a cell structure with a dense cell density is formed in a circular shape on the center side, and a cell structure with a coarse cell density is formed on the outer peripheral side. Also in this embodiment, when the flow rate of the first fluid is increased, the heat exchange efficiency is lowered and the effect of preventing overheating is obtained.

  FIG. 5B shows a third embodiment of the honeycomb structure 1 constituting the heat exchange member 10. The heat exchange member 10 of Embodiment 3 has two regions with a semicircular cross section, one semicircular region having a dense cell density, and the other semicircular region having a coarse cell density. It is embodiment formed as.

  FIG. 5C shows a fourth embodiment of the honeycomb structure 1 constituting the heat exchange member 10. The heat exchange member 10 of the fourth embodiment is an embodiment in which a hollow cell structure without the partition wall 4 on the center side is formed in a circular cross section, and a cell structure having a dense cell density is formed on the outer peripheral side.

  FIG. 5D shows a fifth embodiment of the honeycomb structure 1 constituting the heat exchange member 10. In the heat exchange member 10 of the fifth embodiment, a plurality of hollow circular cell structures without the partition walls 4 are formed side by side on the outer peripheral side.

  FIG. 6 shows a perspective view of a heat exchanger 30 including the heat exchange member 10 of the present invention. As shown in FIG. 6, the heat exchanger 30 is formed by a heat exchange member 10 and a casing 21 that includes the heat exchange member 10 therein. The cells 3 of the honeycomb structure 1 become the first fluid circulation part 5 through which the first fluid flows. The heat exchanger 30 is configured such that a first fluid having a temperature higher than that of the second fluid flows in the cells 3 of the honeycomb structure 1. In addition, an inlet 22 and an outlet 23 for the second fluid are formed in the casing 21, and the second fluid circulates on the outer peripheral surface 12 h of the metal tube 12 of the heat exchange member 10.

  That is, the second fluid circulation portion 6 is formed by the inner surface 24 of the casing 21 and the outer peripheral surface 12 h of the metal tube 12. The second fluid circulation part 6 is a second fluid circulation part formed by the casing 21 and the outer peripheral surface 12 h of the metal tube 12, and the first fluid circulation part 5 and the partition walls 4 and the outer peripheral walls of the honeycomb structure 1. 7. Heat exchange is possible by being separated by the metal pipe 12, and the heat of the first fluid flowing through the first fluid circulation part 5 is received via the partition wall 4, the outer peripheral wall 7, and the metal pipe 12, and is distributed. Heat is transferred to the heated object which is the second fluid. The first fluid and the second fluid are completely separated, and these fluids are configured not to mix.

  The heat exchanger 30 preferably circulates the first fluid having a temperature higher than that of the second fluid, and exchanges heat from the first fluid to the second fluid. When gas is circulated as the first fluid and liquid is circulated as the second fluid, heat exchange between the first fluid and the second fluid can be performed efficiently. That is, the heat exchanger 30 of the present invention can be applied as a gas / liquid heat exchanger.

  The heating element that is the first fluid to be circulated through the heat exchanger 30 of the present invention having the above configuration is not particularly limited as long as it is a medium having heat. For example, if it is gas, the exhaust gas of a motor vehicle etc. are mentioned. In addition, the medium to be heated, which is the second fluid that takes heat from the heating body (exchanges heat), is not particularly limited as a medium, as long as the temperature is lower than that of the heating body.

  Next, the manufacturing method of the heat exchange member 10 of this invention is demonstrated. First, a clay containing ceramic powder is extruded into a desired shape to produce a honeycomb formed body. As the material of the honeycomb structure 1, the above-described ceramics can be used. For example, when manufacturing the honeycomb structure 1 mainly composed of a Si-impregnated SiC composite material, a predetermined amount of C powder, SiC powder, binder Then, water or an organic solvent is kneaded to form a clay and molded to obtain a honeycomb molded body having a desired shape.

  Then, by drying and firing the honeycomb formed body, it is possible to obtain the honeycomb structure 1 in which a plurality of cells 3 serving as gas flow paths are partitioned by the partition walls 4. Subsequently, the temperature of the metal tube 12 is raised, and the honeycomb structure 1 is inserted into the metal tube 12 and integrated by shrink fitting to form the heat exchange member 10. Note that the honeycomb structure 1 and the metal pipe 12 may be joined by brazing, diffusion bonding, or the like in addition to shrink fitting.

2. Decrease in heat exchange efficiency by heat transfer reduction part Next, the heat exchange member 10 provided with the heat transfer reduction part 40 will be described. The heat exchange member 10 includes a honeycomb structure 1 mainly composed of ceramics and a covering member 11 that covers the honeycomb structure 1. The honeycomb structure 1 includes a cylindrical outer peripheral wall 7 and partition walls 4 that partition and form a plurality of cells 3 that serve as flow paths for the first fluid. The covering member 11 does not mix the first fluid flowing inside the honeycomb structure 1 and the second fluid flowing outside the honeycomb structure 1, and does not mix between the first flow path and the second fluid. The honeycomb structure 1 is coated so that heat exchange is possible. And the heat transfer reduction part 40 which reduces the heat transfer between the honeycomb structure 1 and the coating | coated member 11 is provided in the one part range.

  An embodiment in which the heat transfer reduction unit 40 is provided as the constriction unit 41 will be described with reference to FIGS. 7A to 7D, and FIGS. 8A and 8B. In the heat transfer reduction part 40, the outer peripheral wall 7 which is the outer peripheral part of the honeycomb structure 1 or the outer peripheral wall 7 and the partition walls 4 have a total surface area of the outer peripheral part of 0.3 mm or more with respect to the average diameter of the honeycomb structure 1. On the other hand, the constricted portion 41 is constricted by 10% or more.

  FIG. 7A is tied to the outer peripheral portion of the honeycomb structure 1 on one end face 2 side (first fluid inlet side) in the axial direction, and FIG. 7C is the other end face 2 side (first fluid outlet side). A portion 41 is formed. The constricted portion 41 is formed in a shape in which a part of the end surface 2 is missing. 7B and 7D are embodiments in which a constricted portion 41 is formed on the inner side (center side) of the end surface 2 in the axial direction. 7B has one central portion in the axial direction, and FIG. 7D has a plurality of constricted portions 41 formed therein.

  Such a constricted portion 41 reduces the area where the covering member 11 (for example, the metal pipe 12) that comes into contact with the second fluid and the honeycomb structure 1 are in contact with each other, so that the honeycomb structure 1 and the honeycomb structure 1 are connected to each other. Heat transfer between the covering member 11 and the covering member 11 can be reduced. Therefore, such a heat exchange member 10 hardly generates overheating even when the flow rate of the first fluid increases.

  8A and 8B are enlarged views of the periphery of the constricted portion 41. FIG. FIG. 8A is a schematic diagram showing an embodiment in which a constricted portion 41 is formed on the outer peripheral wall 7. By forming the constricted portion 41 in this way, heat transfer between the honeycomb structure 1 and the covering member 11 (metal tube 12) can be reduced. Moreover, the effect of changing the heat exchange efficiency with respect to the flow rate of the first fluid can be obtained. Specifically, the heat recovery efficiency when the flow rate is large can be reduced by providing the heat transfer reduction unit 40 (constriction unit 41). This is because when the first fluid has a low flow rate, heat can be transferred to the second fluid even if the heat transfer area is small, but when the first fluid has a high flow rate, if the heat transfer area is small, heat cannot be transferred to the second fluid.

  FIG. 8B is a schematic view showing an embodiment in which a constricted portion 41 is formed by the outer peripheral wall 7 and the partition wall 4. Such a constricted portion 41 can reduce heat transfer between the honeycomb structure 1 and the covering member 11 (metal tube 12), as in FIG. 8A. In addition, the effect of changing the heat exchange efficiency with respect to the flow rate of the first fluid is obtained, and the heat recovery efficiency when the flow rate is high can be reduced by increasing the heat transfer reduction unit 40 (constriction unit 41). .

  In FIG. 9, the heat transfer reduction part 40 is a heat insulating material 42 provided in a range of 10% or more with respect to the total surface area of the outer peripheral portion of the honeycomb structure 1 between the honeycomb structure 1 and the covering member 11. Fig. 4 shows a formed embodiment. By having the heat transfer reduction part 40 formed of such a heat insulating material 42, the effect of reducing the heat transfer between the honeycomb structure 1 and the coating | coated member 11 (metal pipe 12) is acquired. In addition, the effect of changing the heat exchange efficiency with respect to the flow rate of the first fluid is obtained, and the heat recovery efficiency when the flow rate is large can be reduced by providing the heat transfer reduction unit 40 (heat insulating material 42). .

3. Reduction of thermal shock by agitation means The heat exchange member 10 preferably includes agitation means for agitating the flow of the first fluid. By providing the agitation means, it is possible to reduce the temperature non-uniformity downstream of the heat exchange member 10, and to reduce the damage caused by the thermal shock of the downstream components.

  10A and 10B, the main component is ceramics having a cylindrical outer peripheral wall 7 and partition walls 4 that define a plurality of cells 3 that serve as a flow path for the first fluid, and at least one of them in the axial direction. An embodiment in which the end face 2 includes a honeycomb structure 1 having one or more convex portions 44 or concave portions 45 having an axial length of 1 mm or more, and a covering member 11 covering the honeycomb structure 1 is shown. . The convex portion 44 or the concave portion 45 is a stirring means.

  FIG. 10A is a schematic diagram showing the heat exchange member 10 in which the honeycomb structure 1 has a convex portion 44 on the end face 2 in the axial direction. FIG. 10B is a schematic view showing the heat exchange member 10 in which the honeycomb structure 1 has a recess 45 in the end face 2 in the axial direction. By the convex portion or the concave portion, the gas flow can be turbulent, temperature non-uniformity downstream of the heat exchange member 10 can be reduced, and damage due to thermal shock of downstream components can be reduced.

  FIG. 11A includes a stirring plate 48 in the covering member 11 for stirring the first fluid flowing through the cells 3 of the honeycomb structure 1 along with the honeycomb structure 1 in the axial direction of the honeycomb structure 1. An embodiment is shown. The stirring plate 48 is a stirring means. The stirring plate 48 can be installed on either the upstream side or the downstream side of the honeycomb structure 1. Alternatively, when a plurality of honeycomb structures 1 are arranged in series in the covering member 11, the stirring plate 48 can be installed between the honeycomb structures 1 and the honeycomb structures 1, that is, in the middle stage. The stirring plate 48 may be disposed so as to be in contact with the end face of the honeycomb structure 1 or may be disposed separately. Examples of the material of the stirring plate 48 include metals. An example of the stirring plate 48 is shown in FIGS. 11B to 11D. The shape of the stirring plate 48 is not particularly limited as long as the shape can stir the first fluid. By providing such a stirring plate 48, the flow rate characteristic of the first fluid can be changed. Thereby, the damage by the thermal shock of the components downstream of the heat exchange member 10 can be reduced.

  FIG. 12 shows a honeycomb structure 1 and a covering member 11 that covers the honeycomb structure 1 having at least one small diameter portion or a bulging large diameter portion confined in a portion not covering the honeycomb structure 1; Embodiment of the heat exchange member 10 provided with this is shown. The covering member 11 may be provided with either the small diameter part or the large diameter part or both. That is, if the covering member 11 has a curved portion in a portion where the honeycomb structure 1 is not covered, the first fluid can be stirred in the curved portion, and the heat of the components downstream of the heat exchange member 10 can be stirred. Damage due to impact can be reduced.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these Examples.

(Deterioration of heat exchange efficiency due to cell structure)
(1) Heat exchange member (preparation of clay)
First, 70% by mass of SiC powder having an average particle size of 45 μm, 10% by mass of SiC powder having an average particle size of 35 μm, and 20% by mass of SiC powder having an average particle size of 5 μm were mixed to prepare a mixture of SiC powders. 100 parts by mass of this SiC powder mixture was mixed with 4 parts by mass of binder and water, and kneaded using a kneader to obtain a kneaded product. This kneaded material was put into a vacuum kneader to produce a columnar clay.

(Extrusion molding)
Next, the kneaded material was extruded to form a honeycomb formed body. In extrusion molding, the shape and thickness of the outer peripheral wall 7, the thickness of the partition walls 4, the shape of the cells, the cell density, and the like were made desired by selecting an appropriate form of die and jig. The base was made of a hard metal that does not easily wear. The honeycomb molded body was formed such that the outer peripheral wall 7 was formed into a cylindrical shape and the inside of the outer peripheral wall 7 was divided into square lattices by the partition walls 4. Further, these partition walls 4 were formed so as to be parallel to each other at equal intervals in each of the directions orthogonal to each other and to cross the inside of the outer peripheral wall 7 straightly. Thereby, the cross-sectional shape of the cell 3 other than the outermost peripheral portion inside the outer peripheral wall 7 was made square.

(Dry)
Next, the honeycomb formed body obtained by extrusion molding was dried. First, the honeycomb formed body was dried by an electromagnetic heating method, and subsequently dried by an external heating method. By such two-stage drying, moisture corresponding to 97% or more of the total moisture contained in the honeycomb formed body before drying was removed from the honeycomb formed body.

(Degreasing, impregnation and firing of Si metal)
Next, the honeycomb formed body was degreased at 500 ° C. for 5 hours in an air atmosphere. Further, a lump of metal Si was placed on the honeycomb structure 1 obtained by such degreasing and fired at 1450 ° C. for 4 hours in an inert gas under vacuum or reduced pressure. During the firing, the lump of metal Si placed on the honeycomb structure 1 was melted, and the outer peripheral wall 7 and the partition walls 4 were impregnated with metal Si. When the thermal conductivity of the outer peripheral wall 7 and the partition wall 4 was set to 100 W / (m · K), 70 parts by mass of metal Si mass was used with respect to 100 parts by mass of the honeycomb structure. Further, when the thermal conductivity of the outer peripheral wall 7 and the partition walls 4 was set to 150 W / (m · K), 80 parts by mass of metal Si mass was used with respect to 100 parts by mass of the honeycomb structure. The heat exchange member 10 was obtained through such firing. In addition, about the more detailed form of the heat exchange member 10, etc., it mentions when demonstrating each Example and each comparative example separately below.

(Reference examples A ₁ and B ₁ , Examples 1 to 6)
A heat exchange member 10 having a cylindrical outer peripheral wall 7 having the same structure as that of FIG. 1 was manufactured. Specifically, the heat exchange member 10 having a diameter of 42 mm, a total length of 100 mm, a thickness of the outer peripheral wall 7 of 1.0 mm, and a thermal conductivity of 150 W / (m · K) of the outer peripheral wall 7 and the partition wall 4 was manufactured. It has cell structures A and B as shown in FIG. 2A, and regions X and Y are separated by a boundary 9 as shown in FIG. 2B. The specific cell structure is shown in Table 1. The reference examples A ₁ and B ₁ have a single cell structure.

(Reference examples A ₂ and B ₂ , Examples 7 to 9 and Comparative Examples 1 to 3)
In the same manner as described above, a heat exchange member 10 having a cylindrical outer peripheral wall 7 having different cell structures A and B was manufactured. Specifically, the heat exchange member 10 having a diameter of 42 mm, a total length of 100 mm, a thickness of the outer peripheral wall 7 of 1.0 mm, and a thermal conductivity of 150 W / (m · K) of the outer peripheral wall 7 and the partition wall 4 was manufactured. It has cell structures A and B as shown in FIG. 2A, and regions X and Y are separated by a boundary 9 as shown in FIG. 2B. The specific cell structure is shown in Table 2. The reference examples A ₂ and B ₂ have a single cell structure.

(2) Heat Exchanger By housing the heat exchange member 10 of each of the above-described embodiments and comparative examples in the casing 21, the heat exchanger 30 (heat exchange having basically the same structure as that shown in FIG. 6). Was prepared. About the casing 21, the thing of the shape where the clearance gap between the outer peripheral wall 7 of the heat exchange member 10 and the wall surface of the casing 21 becomes 1 mm in each part was used. That is, the heat exchange member having the cylindrical outer peripheral wall 7 was accommodated in the cylindrical casing 21.

(3) Heat Exchange Test In the heat exchanger 30 described above, a heat exchange test was performed using atmospheric gas as the first fluid and water as the second fluid. The temperature of the atmospheric gas was set to 400 ° C., the flow rate was set to 5 to 15 g / s, and the flow rate of water was set to 10 L / min. In addition, the heat exchange test includes the atmospheric gas outlet temperature (the temperature of the atmospheric gas immediately after being discharged from the end on the outlet side of the heat exchange member 10), and the water outlet temperature (water when passing through the outlet of the casing 21). (Temperature) was confirmed to stabilize.

The temperature of the first fluid immediately before flowing into the end portion on the inlet side of the heat exchange member 10 is “inlet gas temperature”, and the temperature of the first fluid immediately after discharge from the end portion on the outlet side of the heat exchange member is “outlet gas”. It was measured as “Warm”. Further, the temperature of water passing through the inlet of the casing 21 was measured as “inlet water temperature”. From these temperatures, the heat exchange efficiency (%) was calculated by the following formula. The results are shown in Tables 1-2.
Heat exchange efficiency (%) = (inlet gas temperature−outlet gas temperature) / (inlet gas temperature−inlet water temperature) × 100

As shown in Table 1, in Examples 1 to 6, the larger value of S _X / S _Y or S _Y / S _X of the ratio of the opening areas of the regions X and Y is 1.05 to 2.0. As a result, λ ₁ / λ ₂ became larger than the larger value of the reference example (reference example A ₁ : 1.59). That is, it can be said that the heat exchange efficiency decreases as the flow rate of the first gas increases.

As shown in Table 2, in Examples 7 to 9, the larger value of S _X / S _Y or S _Y / S _X of the ratio of the opening areas of the regions X and Y is 1.05 to 2.0. As a result, λ ₁ / λ ₂ became larger than the larger value of the reference example (reference example A ₂ : 1.48). That is, it can be said that the heat exchange efficiency decreases as the flow rate of the first gas increases.

As described above, the larger value of S _X / S _Y or S _Y / S _X in the ratio of the opening areas of the regions X and Y is 1.05 to 2.0. It can be said that the heat exchange efficiency decreases as the flow rate increases. That is, even if the flow rate of the first gas is increased, the heat exchange member 10 is less likely to generate overheating.

  The present invention can be used as a heat exchange member used by being mounted on a heat exchanger.

1: honeycomb structure, 2: end face (in axial direction), 3: cell, 3a: cell structure part, 4: partition wall, 5: first fluid circulation part, 6: second fluid circulation part, 7: outer peripheral wall, 7h: outer peripheral surface (of honeycomb structure), 9: boundary, 10: heat exchange member, 11: covering member, 12: metal tube, 12h: outer peripheral surface of (metal tube), 21: casing, 22: (second 23: (second fluid) outlet, 24: inner surface of (casing), 30: heat exchanger, 40: heat transfer reducing part, 41: constricted part, 42: heat insulating material, 44 : Convex part, 45: concave part, 48: stirring plate.

Claims (11)

A plurality of cells that penetrate from one end portion to the other end portion to serve as a flow path for the first fluid, and a partition wall mainly composed of ceramics that forms the plurality of cells are formed. A cell structure;
Provided on the outer periphery of the cell structure part, mainly composed of ceramics, the first fluid and the second fluid without mixing the first fluid and the second fluid flowing on the outer periphery side of the cell structure part. An outer peripheral wall that intervenes heat transfer with the two fluids, and a honeycomb structure comprising:
The cell structure portion has a cell structure having two or more different aperture ratios in a cross section perpendicular to the axial direction, and when divided into two regions X and Y each having a half of the cross-sectional area, Assuming that the cell structures having the largest areas in the regions X and Y are the cell structure A and the cell structure B, and the total opening areas of the respective regions X and Y are S _X and S _Y , S _X / S _Y or S _Y / The larger value of S _X is 1.05 to 2.0,
When the flow rate before the flow of the first fluid flowing into the cell structure portion changes, and when certain flow rates V ₁ and V ₂ have the same fluid temperature, a relationship of V ₂ / V ₁ ≧ 2 is established. , Let λ ₁ and λ ₂ be the heat exchange efficiencies of the flow rates V ₁ and V ₂ , respectively.
Suppose that the heat exchange efficiencies of V ₁ and V ₂ are λ _1A and λ _2A , respectively, in the case where the cell structure portion is composed only of the cell structure A,
When the heat exchange efficiencies of V ₁ and V _{2 in} the case where the cell structure part is composed of only the cell structure B are λ _1B and λ _2B , respectively,
A heat exchange member in which λ ₁ / λ ₂ is larger than the larger value of λ _1A / λ _2A and λ _1B / λ _2B .   The heat exchange member according to claim 1, wherein the honeycomb structure has a partition wall thickness of 0.15 to 0.64 mm. The honeycomb structure, the heat exchanger member according to claim 1 or 2 cell density of the cell is 4.7 to 62 cells / cm ^2.   The heat exchange member according to any one of claims 1 to 3, wherein the honeycomb structure has an opening ratio of the cells of 40% to 80%. A honeycomb structure mainly composed of ceramics having a cylindrical outer peripheral wall and partition walls that partition and form a plurality of cells serving as flow paths for the first fluid;
Without mixing the first fluid flowing inside the honeycomb structure and the second fluid flowing outside the honeycomb structure, between the first flow path and the second fluid. And a covering member that covers the honeycomb structure so that heat exchange is possible,
A heat transfer reduction part that reduces heat transfer between the honeycomb structure and the covering member is provided in a part of the range,
The first fluid flowing through the cell and the second fluid flowing outside the covering member are not mixed with each other through the outer peripheral wall of the honeycomb structure and the covering member. A heat exchange member that exchanges heat between the second fluid and the second fluid.   The heat transfer reducing portion is the outer peripheral wall which is the outer peripheral portion of the honeycomb structure, or the outer peripheral wall and the partition walls are 0.3 mm or more with respect to the average diameter of the honeycomb structure, and the total surface area of the outer peripheral portion The heat exchange member according to claim 5, wherein the heat exchange member is a constricted portion constricted by 10% or more.   The heat transfer reduction portion is formed of a heat insulating material provided in a range of 10% or more with respect to the total surface area of the outer peripheral portion of the honeycomb structure between the honeycomb structure and the covering member. The heat exchange member as described in. A honeycomb structure mainly composed of ceramics having a cylindrical outer peripheral wall and partition walls that partition and form a plurality of cells serving as flow paths for the first fluid;
Without mixing the first fluid flowing inside the honeycomb structure and the second fluid flowing outside the honeycomb structure, between the first flow path and the second fluid. And a covering member that covers the honeycomb structure so that heat exchange is possible,
And further comprising stirring means for stirring the flow of the first fluid,
The first fluid flowing through the cell and the second fluid flowing outside the covering member are not mixed with each other through the outer peripheral wall of the honeycomb structure and the covering member. A heat exchange member that exchanges heat between the second fluid and the second fluid.   9. The heat exchange member according to claim 8, wherein as the stirring means, at least one end face in the axial direction of the honeycomb structure is formed with one or more convex portions or concave portions having a length in the axial direction of 1 mm or more. .   The stirrer is a stirrer for stirring the first fluid provided in the covering member alongside the honeycomb structure in the axial direction of the honeycomb structure. Heat exchange member.   The heat exchanging member according to claim 8, wherein the stirring means is a covering member having one or more small-diameter portions constricted in a portion where the honeycomb structure is not covered or a bulging large-diameter portion.

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