Heat Exchanger Comprising Wave-shaped Fins

Abstract

A heat exchanger for exchanging heat between a first fluid and a second fluid is disclosed; wherein the heat exchanger has improved thermal efficiency and low fluid back pressure. The heat exchanger comprises conduits for conveying the first fluid, wherein the conduits include a plurality of flow passages. The flow passages are defined by a plurality of fins that are continuous along the direction of flow of the first fluid. Each fin includes a wave-shaped region, and adjacent fins sub-divide each flow passage into first and second sections that are interposed by a third section. The wave-shape of the fins creates a continuously varying cross-sectional area for each third section. The variation of the cross-sectional area of the third section, coupled with the wave-shape of the fins, induces a swirl flow between the third section and each of the first and second sections. This swirl flow improves the efficiency of the overall convection heat transfer in each conduit. Further, the overall cross-sectional area of each conduit remains constant even as the cross-sectional areas of individual flow passages changes, which mitigates the development of back pressure in the flow of the first fluid.

1 . A heat exchanger that thermally couples a first fluid and a second fluid, wherein the heat exchanger comprises:
 (1) a first plate comprising a first material that is thermally conductive, wherein the first plate comprises;
 (i) a first conduit for conveying the first fluid along a first direction, wherein the first conduit comprises at least one first channel; and 
 (ii) a first plurality of first fins, wherein each first fin is continuous along the first direction, and wherein each first fin comprises a first fin portion that has a first periodic shape having a first periodicity along the first direction; and 
   (2) a second plate comprising the first material, wherein the second plate comprises;
 (i) a second conduit for conveying the first fluid along the first direction, wherein the second conduit comprises at least one second channel; and 
 (ii) a second plurality of second fins, wherein each second fin is continuous along the first direction; 
   wherein the first plurality of first fins and the second plurality of second fins collectively define a plurality of passages for conveying the second fluid along the first direction, and wherein each of the plurality of passages comprises a first section, second section, and third section; and   wherein the cross-sectional area of the first section varies along the first direction based on the first periodicity, and wherein the variation of the cross-sectional area of the first section induces flow of the second fluid between the first section and each of the second section and third section.   
     
     
         2 . The heat exchanger of  claim 1  wherein each second fin is substantially straight along a second direction that is orthogonal with the first direction. 
     
     
         3 . The heat exchanger of  claim 1  wherein each second fin comprises a second fin portion that has the first periodic shape having the first periodicity along the first direction. 
     
     
         4 . The heat exchanger of  claim 3  wherein the first plurality of first fins and the second plurality of second fins are arranged along the first direction with a phase offset. 
     
     
         5 . The heat exchanger of  claim 4  wherein the phase offset is 90 degrees. 
     
     
         6 . The heat exchanger of  claim 4  wherein the phase offset is 180 degrees. 
     
     
         7 . The heat exchanger of  claim 4  wherein the phase offset is 180 degrees. 
     
     
         8 . The heat exchanger of  claim 1  wherein each first fin further comprises a third fin portion that is substantially straight along the first direction, and wherein the third fin portion interposes the first plate and the first fin portion. 
     
     
         9 . The heat exchanger of  claim 8  wherein each second fin further comprises a fourth fin portion that is substantially straight along the first direction, and further wherein the fourth fin portion interposes the second plate and the second fin portion. 
     
     
         10 . The heat exchanger of  claim 8  wherein the first fin portion has a first height and the third fin portion has a second height, and wherein the first height and the second height are substantially equal. 
     
     
         11 . The heat exchanger of  claim 8  wherein the first fin portion has a first height and the third fin portion has a second height, and wherein the first height and the second height are unequal. 
     
     
         12 . The heat exchanger of  claim 1  wherein the variation of the cross-sectional area of the first section induces turbulence in the second fluid in at least one of the second section and third section. 
     
     
         13 . The heat exchanger of  claim 1  wherein the variation of the cross-sectional area of the first section induces a swirl flow of the second fluid in at least one of the second section and third section. 
     
     
         14 . The heat exchanger of  claim 1  wherein the variation of the cross-sectional area of the first section induces a vortex flow of the second fluid in at least one of the second section and third section. 
     
     
         15 . A heat exchanger that thermally couples a first fluid and a second fluid, wherein the heat exchanger comprises:
 a first conduit for conveying the first fluid along a first direction; and   a second conduit for conveying the second fluid along the first direction, wherein the second conduit comprises plurality of fins that are continuous along the first direction, and wherein each of the plurality of fins comprises a first fin portion that has a first periodic shape having a first periodicity along the first direction;   wherein the plurality of fins collectively define a plurality of passages in the second conduit, and wherein each of the plurality of passages comprises a first section, second section, and third section, and wherein the first section has a cross-sectional area that varies along the first direction based on the first periodicity, and further wherein the variation of the cross-sectional area of the first section induces flow of the second fluid between the first section and each of the second section and third section.   
     
     
         16 . The heat exchanger of  claim 12  wherein the variation of the cross-sectional area of the first section induces turbulence in at least one of the second section and third section. 
     
     
         17 . The heat exchanger of  claim 12  wherein the variation of the cross-sectional area of the first section induces swirl flow in at least one of the second section and third section. 
     
     
         18 . The heat exchanger of  claim 12  wherein the variation of the cross-sectional area of the first section induces vortex flow in at least one of the second section and third section. 
     
     
         19 . A method comprising:
 conveying a first fluid in a first conduit, wherein the first conduit conveys the first fluid along a first direction;   conveying a second fluid in a plurality of passages, wherein the second fluid and first fluid are thermally coupled via the first conduit and the plurality of passages, and wherein each of the plurality of passages is continuous along the first direction and comprises a first section, second section, and third section, and wherein the cross-sectional area of the first section varies along the first direction based on the first periodicity; and   inducing a first flow of the second fluid between the first section and each of the second section and third section, wherein the first flow is induced by the variation of the cross-sectional area of the first section along the first direction.   
     
     
         20 . The method of  claim 19  wherein the first flow is induced such that a turbulent flow is induced in at least one of the second section and third section. 
     
     
         21 . The method of  claim 19  wherein the first flow is induced such that a swirl flow is induced in at least one of the second section and third section. 
     
     
         22 . The method of  claim 19  wherein the first flow is induced such that a vortex flow is induced in at least one of the second section and third section. 
     
     
         23 . The method of  claim 19  further comprising providing the first conduit and second conduit, wherein providing the first conduit and second conduit are provided by operations comprising:
 providing a first plate, wherein the first plate comprises the first conduit and a first plurality of first fins; 
 providing a second plate, wherein the first plate comprises a second conduit for conveying the first fluid along the first direction, and wherein the second conduit comprises at least one second channel, and further wherein the second plate comprises a second plurality of second fins; 
 wherein the first plate and second plate are provided such that the first plurality of first fins and second plurality of second fins collectively define the plurality of passages.