Heat exchanger

Abstract

In a heat exchanger, a tube is adapted to exchange heat between a first fluid flowing therein and a second fluid flowing through outside of the tube, and an inner fin is disposed in the tube to divide a flow passage in the tube into a plurality of flow paths. The inner fin includes a plurality of fin portions with different specifications, and the fin portions are arranged in series with respect to a flow direction of the first fluid. Furthermore, the fin portion with the smallest flowing resistance of the first fluid among the plurality of fin portions is arranged on an upstream side of the flow direction of the first fluid with respect to at least an another fin portion. Accordingly, heat exchange performance in the entire heat exchanger can be effectively improved.

1 . A heat exchanger comprising:
 a tube having therein a flow passage through which a first fluid flows, the tube being adapted to exchange heat between the first fluid and a second fluid flowing through an outer periphery of the tube; and   an inner fin provided in the tube to promote the heat exchange between the first fluid and the second fluid, the inner fin being configured to divide the flow passage in the tube into a plurality of flow paths, wherein   the inner fin includes a plurality of fin portions with different specifications,   the fin portions are arranged in series with respect to a flow direction of the first fluid, and   the fin portion with the smallest flowing resistance of the first fluid among the plurality of fin portions is arranged on an upstream side of the flow direction of the first fluid with respect to at least an another fin portion.   
   
   
       2 . The heat exchanger according to  claim 1 , wherein the fin portion with the largest flowing resistance of the first fluid among the plurality of fin portions is arranged on a downstream side of the flow direction of the first fluid with respect to the other fin portion. 
   
   
       3 . The heat exchanger according to  claim 1 , wherein the fin portions are arranged symmetrically with respect to a center line of the inner fin in the flow direction of the first fluid. 
   
   
       4 . The heat exchanger according to  claim 1 , wherein the fin portions are constructed of at least first and second different kinds of fin portions. 
   
   
       5 . The heat exchanger according to  claim 1 , wherein the plurality of fin portions include
 a straight fin portion having a plurality of wall surfaces extending linearly in the flow direction of the first fluid, the wall surfaces being configured to divide the flow passage of the tube into the plurality of flow paths, and   a louver fin portion including a plurality of flat portions substantially in parallel to the flow direction of the first fluid, and a plurality of louvers provided at the flat portions along the flow direction of the first fluid, the louvers being formed by cutting and raising a part of the flat portion,   wherein the straight fin portion is arranged on an upstream side of the flow direction of the first fluid, with respect to the louver fin portion.   
   
   
       6 . The heat exchanger according to  claim 1 , wherein the plurality of fin portions include
 a straight fin portion having a plurality of wall surfaces extending linearly in the flow direction of the first fluid, the wall surfaces being configured to divide the flow passage of the tube into the plurality of flow paths, and   an offset fin portion including wall portions arranged in a zigzag shape along the flow direction of the first fluid, the wall portions being configured to divide the flow passage of the tube into the plurality of flow paths,   wherein the straight fin portion is arranged on an upstream side of the flow direction of the first fluid, with respect to the offset fin portion.   
   
   
       7 . The heat exchanger according to  claim 1 , wherein
 the inner fin is a louver fin including a plurality of flat portions substantially in parallel to the flow direction of the first fluid, and a plurality of louvers provided at the flat portions along the flow direction of the first fluid, the louver being formed by cutting and raising a part of the flat portion,   the fin portions are configured to have different louver pitches in the louvers, and   the fin portion with the largest louver pitch among the plurality of fin portions is arranged on an upstream side of the flow direction of the first fluid, with respect to at least an another fin portion.   
   
   
       8 . The heat exchanger according to  claim 1 , wherein
 the fin portions have different fin pitches, and   the fin portion with the largest fin pitch among the fin portions is arranged on an upstream side of the flow direction of the first fluid, with respect to at least an another fin portion.   
   
   
       9 . The heat exchanger according to  claim 1 , wherein the fin portions are continuously arranged in the flow direction of the first fluid such that flow resistances of the first fluid in the fin portions are increased as toward downstream in the flow direction of the first fluid. 
   
   
       10 . The heat exchanger according to  claim 1 , wherein the first fluid flowing in the tube generally has a temperature higher than that of the second fluid. 
   
   
       11 . The heat exchanger according to  claim 1 , further comprising:
 a plurality of the tubes each of which defines therein the refrigerant passage in which the first fluid flows, the tubes being stacked in a stacking direction; and   a plurality of outer fins each of which is located between adjacent tubes.