Heat Exchanger

Abstract

A heat exchanger has a first fin having a hole, a collar attached to the first fin and associated with the hole, and a bluff body carried by the first fin. The bluff body is partially directly upstream of the collar. A heat exchanger has a fin having a hole, a collar attached to the fin and associated with the hole, and a bluff body associated with the fin. A configuration of the bluff body is associated with a fin pitch separation distance of the heat exchanger. A method of increasing a heat exchange efficiency of a heat exchanger is provided that includes passing an air flow adjacent a surface of a fin, obstructing the air flow with a bluff body, reducing a thickness of a thermal boundary layer, and locating a reduced thickness portion of the thermal boundary layer adjacent to a collar associated with the fin.

1 . A heat exchanger, comprising:
 a first fin having a hole;   a collar attached to the first fin and associated with the hole; and   a bluff body carried by the first fin wherein the bluff body is at least partially directly upstream of a portion of the collar.   
     
     
         2 . The heat exchanger according to  claim 1 , further comprising:
 a second fin separated from the first fin by a fin pitch separation distance and wherein the bluff body comprises a radius having a value between about 0.5 to about 1.5 times the fin pitch separation distance.   
     
     
         3 . The heat exchanger according to  claim 1 , further comprising:
 a second fin separated from the first fin by a fin pitch separation distance wherein the bluff body has a maximum length measured substantially transverse to an incoming flow of air and wherein about one-half the maximum length is a value between about 0.5 to about 1.5 times the fin pitch separation distance.   
     
     
         4 . The heat exchanger according to  claim 1 , wherein the bluff body is hemispherical in shape. 
     
     
         5 . The heat exchanger according to  claim 4 , wherein the bluff body is formed as an indentation of the fin. 
     
     
         6 . The heat exchanger according to  claim 4 , wherein the bluff body is secured to the fin. 
     
     
         7 . The heat exchanger according to  claim 1 , further comprising:
 a second fin separated from the first fin by a fin pitch separation distance wherein the bluff body is located on the fin and offset from the collar in an upstream direction by a distance of about one to about five times a diameter of the bluff body.   
     
     
         8 . The heat exchanger according to  claim 1 , further comprising:
 a second fin separated from the first fin by a fin pitch separation distance wherein the bluff body is located on the fin and offset from the collar in an upstream direction by a distance of about one to about five times a maximum length maximum length of the bluff body wherein the maximum length is measured substantially transverse to an incoming flow of air.   
     
     
         9 . A heat exchanger, comprising:
 a fin having a hole;   a collar attached to the fin and associated with the hole; and   a bluff body associated with the fin wherein a configuration of the bluff body is associated with a fin pitch separation distance of the heat exchanger.   
     
     
         10 . The heat exchanger according to  claim 9 , wherein the bluff body comprises a radius having a value between about 0.5 to about 1.5 times the fin pitch separation distance. 
     
     
         11 . The heat exchanger according to  claim 9 , wherein the bluff body has a maximum length measured substantially transverse to an incoming flow of air and wherein about one-half the maximum length is a value between about 0.5 to about 1.5 times the fin pitch separation distance. 
     
     
         12 . The heat exchanger according to  claim 9 , wherein the bluff body is formed as an indentation of the fin. 
     
     
         13 . The heat exchanger according to  claim 9 , wherein the bluff body is located on the fin and offset from the collar in an upstream direction by a distance of about one to about five times a diameter of the bluff body. 
     
     
         14 . The heat exchanger according to  claim 9 , wherein the bluff body is located on the fin and offset from the collar in an upstream direction by a distance of about one to about five times a maximum length maximum length of the bluff body wherein the maximum length is measured substantially transverse to an incoming flow of air. 
     
     
         15 . A method of increasing a heat exchange efficiency of a heat exchanger, comprising:
 passing an air flow adjacent a surface of a fin of the heat exchanger;   at least partially obstructing the air flow with a bluff body associated with the fin;   reducing a thickness of a thermal boundary layer downstream of the bluff body; and   locating a reduced thickness portion of the thermal boundary layer adjacent to a collar associated with the fin.   
     
     
         16 . The method of  claim 15 , wherein the locating the reduced thickness portion of the thermal boundary layer adjacent the collar is accomplished by providing the bluff body with a dimension that is about 0.5 to about 1.5 times a fin pitch of the heat exchanger. 
     
     
         17 . The method of  claim 16 , wherein the dimension is a radius of the bluff body. 
     
     
         18 . The method of  claim 15 , wherein the locating the reduced thickness portion of the thermal boundary layer adjacent the collar is accomplished by locating the bluff body upstream from the collar by about one to about five times a dimension of the bluff body. 
     
     
         19 . The method of  claim 18 , wherein the dimension is a diameter of the bluff body. 
     
     
         20 . The method of  claim 17 , wherein the bluff body is hemispherical in shape and has a radius of about 0.5 to about 1.5 times a fin pitch of the heat exchanger and wherein the bluff body is located about 1 to about 5 times a diameter of the bluff body upstream from the collar.