Heat Exchanger

The present disclosure relates to a heat exchanger.

Priority is claimed on Japanese Patent Application No. 2022-089006, filed May 31, 2022, the content of which is incorporated herein by reference.

In a so-called fin tube type heat exchanger including plate fins and heat transfer tubes, it is desired to improve a heat transfer coefficient of the plate fin in order to improve heat exchange efficiency. Patent Document 1 discloses a configuration in which a plate fin surrounding the heat transfer tube is cut, a guide fin inclined with respect to a gas flow direction is formed, and the guide fin guides a gas flow to a downstream region of the heat transfer tube in the gas flow direction.

Patent Document 2 discloses a configuration in which ventilation resistance is reduced by providing notch portions that expand toward an upstream side in a gas flow direction at positions which are located at an equal distance from two adjacent heat transfer tubes among end edge portions of the plate fins on the upstream side in the gas flow direction.

Patent Document 3 discloses a configuration in which a curved line or a bent line is continuously formed in a direction of stages of heat transfer tubes at a distance of approximately half of a distance between the heat transfer tubes in a column direction of the heat transfer tubes, and the plate fins are cut such that projected portions and recessed portions are engaged with each other as a whole. In Patent Document 3, the plate fins are formed in this way, and thus, a variation in the heat transfer distance from each heat transfer tube to the edge of the plate fin is reduced without changing an area of the plate fin. Therefore, efficiency of the fin can be improved.

Patent Document 1: PCT International Publication No. WO2007/004457.

Patent Document 2: Japanese Patent No. 3910475.

Patent Document 3: Japanese Unexamined Patent Application, First Publication No. 2001-033183.

In the fin tube type heat exchangers described in Patent Documents 1 to 3, an amount of heat exchange can be efficiently increased by increasing a heat transfer coefficient from the gas flow to the plate fin. That is, in the heat exchanger, the amount of heat exchange can be easily improved by increasing the heat transfer area. However, in a case where the heat transfer area is increased, there is a problem that the heat exchanger becomes large and it is difficult to reduce the weight of the heat exchanger.

The present disclosure has been made in view of the above circumstances, and provides a heat exchanger capable of reducing the weight of the heat exchanger while increasing an amount of heat exchange.

In order to solve the above problems, the following configuration is adopted.

According to a first aspect of the present disclosure, a heat exchanger is provided including: a plurality of heat transfer tubes that are disposed in a flow of a gas, extend in a second direction intersecting a first direction in which the gas flows, and are arranged at intervals; and a plurality of plate fins that extend in the first direction, are provided to straddle the plurality of heat transfer tubes, and are arranged at intervals in the second direction, in which the plate fins include a plurality of slits that extend in a third direction and are arranged at intervals in the first direction, the third direction being a direction intersecting both the first direction and the second direction, the plurality of slits have zigzag shapes alternately and obliquely extending toward an upstream side and a downstream side of the first direction in which the gas flows, and patterns of the zigzag shapes match each other.

According to a second aspect of the present disclosure, a heat exchanger is provided including: a plurality of heat transfer tubes that are disposed in a flow of a gas, extend in a second direction intersecting a first direction in which the gas flows, and are arranged in a staggered arrangement in which the plurality of heat transfer tubes are alternately shifted in a third direction, which is a direction intersecting both the first direction and the second direction; and a plurality of plate fins that extend in the first direction, are provided to straddle the plurality of heat transfer tubes, and are arranged at intervals in the second direction, in which the plate fins include holes that penetrate in the second direction on an upstream side of each of the plurality of heat transfer tubes in the first direction.

With the heat exchanger according to the present disclosure, it is possible to reduce the weight of the heat exchanger while increasing the amount of heat exchange.

Next, a heat exchanger according to a first embodiment of the present disclosure will be described with reference to the drawings.

is a diagram showing a schematic configuration of a heat exchanger according to a first embodiment of the present disclosure.

As shown in, a heat exchangeraccording to the first embodiment exchanges heat between a gas G supplied from the outside and a refrigerant R. The heat exchangerincludes heat transfer tubesand plate fins. In the following description, a flow of the gas G for heat exchange in the heat exchanger is simply referred to as a gas flow. In addition, a direction in which the gas G flows is referred to as a first direction D, an upstream side of the gas flow is referred to as a first-direction upstream side D, and a downstream side of the gas flow is referred to as a first-direction downstream side D

The heat transfer tubesare disposed in the gas flow. The heat transfer tubesextend in a second direction Dintersecting the first direction D. A plurality of heat transfer tubesare arranged at intervals in the gas flow. A heat transfer tube groupis formed of the plurality of heat transfer tubesarranged in this manner. The heat transfer tubesin the heat transfer tube groupdescribed in the present embodiment have the same shape, and the refrigerant R flows inside the heat transfer tubes. Although a case where the second direction Din the present embodiment is a direction perpendicular to the first direction Dis shown, the second direction Dis not limited to a direction perpendicular to the first direction D. In the following description, a direction intersecting the first direction Dand the second direction Dis referred to as a third direction D(refer to).

is a cross-sectional view taken along a line II-II of.

As shown in, the heat transfer tubesincluded in the heat transfer tube groupare disposed in a so-called staggered arrangement. In other words, the heat transfer tubesin the heat transfer tube groupare arranged in an orthorhombic grid. That is, the plurality of heat transfer tubesin the heat transfer tube groupare alternately shifted and arranged in the first direction Dand the third direction D.

The heat transfer tubesin the heat transfer tube groupaccording to the present embodiment form a first column Cand a second column Cextending in the first direction D, and the first column Cand the second column Care alternately arranged in the third direction D. In addition, the heat transfer tubesin the first column Care disposed at an interval of a distance Lin the first direction D. Each heat transfer tubein the second column Cis disposed at an interval of a distance Lin the first direction Dand is disposed by being shifted in the first direction Dby a distance L, which is a half of the distance L, with respect to a position of the heat transfer tubein the first column C. In the following description, the heat transfer tubesarranged in the first direction Dmay be referred to as a column (C), and the heat transfer tubesarranged in the third direction Dmay be referred to as a stage (S). The heat transfer tube groupaccording to the present embodiment includes a plurality of columns and a plurality of stages of heat transfer tubes. In addition, for convenience of illustration, in order to show the columns C (C, C) and the stages S in, reference numerals are attached to axes passing through the centers of the heat transfer tubesincluded in the columns C (C, C) and the stages S.

The plate finis provided to extend in the first direction Dand to straddle the plurality of heat transfer tubes. A plurality of plate finsare arranged at intervals in the second direction D(refer to). Each of the plurality of plate finsaccording to the present embodiment is formed in a thin plate shape, and is disposed at an equal interval in the second direction D. The above-described gas flow flows between the plate finsfrom the first-direction upstream side Dto the first-direction downstream side D

The plate finincludes a slit. The slitextends in the third direction D. More specifically, the slitis formed to cross the plate finin the third direction D. A plurality of slitsare arranged at intervals in the first direction D. The plurality of slitspenetrate the plate finsin the second direction Dwhich is a thickness direction of the plate fins. The slitsaccording to the present embodiment are provided for each of the two-stage heat transfer tubesin the heat transfer tube groupthat are adjacent to each other in the first direction D.

The plurality of slitshave zigzag shapes alternately and obliquely extending to the first-direction upstream side Dand the first-direction downstream side D. The plurality of slitshave patterns of the zigzag shapes that match each other. In other words, for example, the plurality of slitsmatch each other at positions of projected portions, which are formed to be projected in the third direction Dtoward the first-direction upstream side D, and positions of recessed portions, which are formed to be recessed in the third direction Dtoward the first-direction downstream side D. In addition, the pattern of the zigzag shape of the slitdescribed in the present embodiment matches a pattern in which the heat transfer tubesare disposed at equal intervals in the third direction D. In addition, amplitude of the zigzag shape of the slitis constant.

The slitextends toward the first-direction upstream side Dat a position between the heat transfer tubesadjacent to each other in the third direction Don the stage S adjacent to the first-direction upstream side D. In addition, the slitextends toward the first-direction downstream side Dat a position between the heat transfer tubesadjacent to each other in the third direction Don the stage S adjacent to the first-direction downstream side D. In the present embodiment, a position of a vertex t of the zigzag shape in the third direction Dmatches the position of the heat transfer tubein the third direction D.

More specifically, in the present embodiment, the position of a folded portion of the projected portion, which is the vertex t of the slitin the third direction D, matches that of the center of the heat transfer tubein the first column C. Similarly, the position of a folded portion of the recessed portion, which is the vertex t of the slitin the third direction D, matches that of the center of the heat transfer tubein the second column C. In addition, in the present embodiment, a distance in the first direction Dbetween the vertex t and the heat transfer tubein the first column Cdisposed at a position closest to the vertex t in the first direction Dis the same as a distance in the first direction Dbetween the vertex t and the heat transfer tubein the second column C. The position of the folded portion of the projected portionor the recessed portionis not limited to a case where the position matches the center position of the heat transfer tube. For example, the position may be slightly shifted from the center position of the heat transfer tube.

In the slitdescribed in the present embodiment, the portion of the slitextending toward the first-direction upstream side Dextends toward the first-direction upstream side Das compared to the center of the heat transfer tubeon the stage S adjacent to the first-direction upstream side D. On the other hand, in the slit, the portion of the slitextending toward the first-direction upstream side Ddoes not extend toward the first-direction upstream side Das compared to the heat transfer tubeon the stage adjacent to the first-direction upstream side D. That is, the slitis located at the same position as a point Pof the heat transfer tubethat is located to be closest to the first-direction upstream side Don the stage S adjacent to the first-direction upstream side D, or at a position that is located toward the first-direction downstream side Das compared to the point P.

Similarly, in the slitdescribed in the present embodiment, the portion of the slitextending toward the first-direction downstream side Dextends toward the first-direction downstream side Das compared to the center of the heat transfer tubeon the stage S adjacent to the first-direction downstream side D. On the other hand, in the slit, the portion of the slitextending toward the first-direction downstream side Ddoes not extend toward the first-direction downstream side Das compared to the heat transfer tubeon the stage S adjacent to the first-direction downstream side D. That is, the slitis located at the same position as a point Pof the heat transfer tubethat is located to be closest to the first-direction downstream side Don the stage S adjacent to the first-direction downstream side D, or at a position that is located toward the first-direction upstream side Das compared to the point P.

In the heat exchangeraccording to the first embodiment, the plate finshave the plurality of slitsthat extend in the third direction Dand are arranged at intervals in the first direction D, the plurality of slitsform zigzag shapes alternately and obliquely extending toward the first-direction upstream side Dand the first-direction downstream side D, and the patterns of the zigzag shapes match each other.

Therefore, in a case where the gas G flows from the first-direction upstream side Dto the first-direction downstream side D, the gas flow is disturbed by the slit, and a temperature boundary layer of the gas flow can be thinned. Therefore, a temperature gradient from the plate finscan be steepened, and an amount of heat exchange can be increased. In addition, the slitis formed in a zigzag shape, and thus a length of the slitcan be increased as compared with a case where the slitis formed in a linear shape. Thereby, the weight of the plate fincan be reduced. Further, since the patterns of the zigzag shapes of the plurality of slitsextending in the third direction Dmatch each other, a distance between the slitsadjacent to each other in the first direction Dcan be made uniform, and a contact area between the gas flow and the plate fins can be secured. As a result, it is possible to prevent a decrease in the amount of heat exchange while reducing development of the temperature boundary layer.

In the heat exchangeraccording to the first embodiment, further, the heat transfer tubesare disposed in a staggered arrangement, and the slitextends toward the first-direction upstream side Dbetween the plurality of heat transfer tubesarranged in the third direction Dto be adjacent to the slitand the first-direction upstream side D

Thereby, in a case where the heat transfer tubesare disposed in a staggered arrangement, it is possible to reduce a distance between the heat transfer tube, which is disposed on the first-direction upstream side Dby one stage as compared to the heat transfer tubeon the stage adjacent to the first-direction upstream side D, and the sliton the first-direction downstream side Dof the heat transfer tube. Therefore, development of the temperature boundary layer on the first-direction downstream side Dof the heat transfer tubecan be prevented, and thus, it is possible to increase the amount of heat exchange.

In the heat exchangeraccording to the first embodiment, further, the position of the vertex t of the zigzag shape in the third direction Dmatches the position of the heat transfer tubein the third direction D.

Thereby, the distance between the heat transfer tubesdisposed in a staggered arrangement and the slitscan be further made uniform.

In the heat exchangeraccording to the first embodiment, further, the slitis provided for each of two-stage heat transfer tubesarranged in the third direction Dand adjacent to each other in the first direction D.

Thereby, it is possible to more effectively increase the amount of heat exchange.

A width of the slitin the first direction Din the first embodiment described above may be formed, for example, to be narrower as the flow velocity of the gas flow is higher and to be wider as the flow velocity of the gas flow is lower. In this manner, even in a case where the flow velocity of the gas flow is low, it is possible to more effectively prevent development of the temperature boundary layer.

Next, a second embodiment of the present disclosure will be described with reference to the drawings. A heat exchangeraccording to the second embodiment is obtained by adding protrusions to the heat exchangeraccording to the first embodiment described above. Therefore, the same parts as those in the first embodiment described above will be denoted by the same reference numerals, and description of the overlapping parts with the first embodiment will be omitted.

is a cross-sectional view of the heat exchanger according to the second embodiment of the present disclosure, and corresponds to.

As shown inand, the heat exchangeraccording to the second embodiment exchanges heat between the gas G supplied from the outside and the refrigerant R, similarly to the heat exchangeraccording to the first embodiment described above. The heat exchangerincludes heat transfer tubes, plate fins, and protrusions.

is an enlarged view of a main part of.

As shown inand, the protrusionsprotrude from the plate finsin the second direction D, and extend in the first direction D. The protrusionsaccording to the present embodiment extend to straddle the plate finsadjacent to each other in the second direction D. The protrusionsare provided in pairs of two on the first-direction upstream side Dand the first-direction downstream side Dof the heat transfer tube. The two protrusionsprovided on the first-direction upstream side Dof the heat transfer tubeare disposed at an interval Lin the third direction D. Similarly, the two protrusionsprovided on the first-direction downstream side Dof the heat transfer tubeare also disposed at an interval Lin the third direction D.

The interval Lis smaller than an outer diameter Rof the heat transfer tube. A case where the interval Laccording to the present embodiment is half the size of the outer diameter Rof the heat transfer tubeis described.

Further, a length of the protrusionin the first direction Dmay be any length as long as the protrusioncan protrude from the heat transfer tubein the first direction. In addition, a thickness of the protrusionin the third direction Dis thinner than a thickness of a tube wall of the heat transfer tube. In the present embodiment, a case where the thickness of the protrusionis approximately half the thickness of the tube wall of the heat transfer tubeis described, but the present invention is not limited thereto.

In the present embodiment, a case where a pair of the protrusionsare disposed at the same interval Lhas been described. On the other hand, the interval between the pair of the protrusionsmay be different in the first-direction upstream side Dand the first-direction downstream side D. In addition, a case where the protrusionaccording to the second embodiment is formed in a flat plate shape extending in the first direction Dwhen viewed in the second direction Dhas been described. On the other hand, the protrusionis not limited to the flat plate shape, and may have, for example, a shape that is slightly curved.

In the second embodiment, the heat exchangerincludes a pair of protrusionson the first-direction upstream side Dand the first-direction downstream side Dof the heat transfer tube.

Thereby, the gas flows in the first direction Doutside the pair of protrusionsin the third direction D, and thus, flow passage areas on the first-direction upstream side Dand the first-direction upstream side Dof the heat transfer tubecan be reduced. Therefore, it is possible to increase the flow velocity of the gas. Therefore, in addition to prevention of development of the temperature boundary layer by the slit, development of the temperature boundary layer on the plate fincan be further prevented.

Further, the heat transfer area of the heat transfer tubecan be increased by the protrusions, and thus, the amount of heat exchange can be further increased.

is an enlarged view of the heat exchanger according to a first modification example of the second embodiment of the present disclosure, and corresponds to.

A case where the protrusionaccording to the second embodiment described above is formed integrally with the heat transfer tubehas been described. On the other hand, the protrusionis not limited to the configuration in which the protrusionis formed integrally with the heat transfer tube. For example, as in the protrusionshown in, the protrusionmay be formed by performing cutting from the plate fin.