Heat exchanger

Abstract

A heat exchanger, in which louver wall surfaces ( 3 c ) are twisted at a predetermined angle (θ1) with respect to a plurality of flat portions ( 3 a ) of fins ( 3 ) and an inter-louver path ( 5 ) is formed between the adjacent louver wall surfaces ( 3 c ), is disclosed. The center points ( 3 d ) of some louver wall surfaces ( 31 c ) are displaced from the center points ( 3 d ) of the other louver wall surfaces ( 32 c ) along the cooling water flow direction (X 1 ). As a result, the real louver pitch height (HLP) is increased beyond the louver pitch heights (HLP1, HLP2) of the louver wall surfaces ( 31 c , 32 c ), respectively. Even in the case where the louver width (L) is reduced, therefore, the cooling air can be caught by the louver wall surfaces ( 3 c ).

1 . A heat exchanger comprising: 
 a plurality of tubes ( 2 ) with an internal fluid flowing therein and stacked in the direction perpendicular to the direction (X 1 ) of the internal fluid flow; and    a plurality of fins ( 3 ) arranged between the tubes ( 2 ) to increase the heat transfer area in contact with an external fluid flowing between the tubes ( 2 );    wherein the fins ( 3 ) have a plurality of flat portions ( 3   a ) substantially parallel to the direction (X 2 ) of the external fluid flow, and a plurality of louver wall surfaces ( 3   c ) twisted at a predetermined angle (θ1) to the flat portions ( 3   a ) are formed on the flat portions ( 3   a ) along the direction (X 2 ) of the external fluid flow, and    wherein the plurality of the louver wall surfaces ( 3   c ) include at least a louver wall surface ( 31   c ) having the center point ( 3   d ) thereof along the louver width (X 4 ) displaced from the center point ( 3   d ) of the other louver wall surfaces ( 32   c ) in the direction (X 1 ) of the internal fluid flow.    
   
   
       2 . A heat exchanger according to  claim 1 , 
 wherein a twisted portion ( 3   e ) where each flat portion ( 3   a ) and each louver wall surface ( 3   c ) cross each, other as viewed along the fin height (X 3 ), is displaced from the center point ( 3   d ) in the direction (X 4 ) along the louver width of the louver wall surface ( 3   c ).    
   
   
       3 . A heat exchanger comprising: 
 a plurality of tubes ( 2 ) with an internal fluid flowing therein and stacked in the direction perpendicular to the direction (X 1 ) of the internal fluid flow; and    a plurality of fins ( 3 ) arranged between the tubes ( 2 ) to increase the heat transfer area in contact with an external fluid flowing between the tubes ( 2 ),    wherein the fins ( 3 ) have a plurality of flat portions ( 3   a ) substantially parallel to the direction (X 2 ) of the external fluid flow, and a plurality of louver wall surfaces ( 3   c ) twisted at a predetermined angle (θ1) to the flat portions ( 3   a ), are formed on the flat portions ( 3   a ) along the direction (X 2 ) of the external fluid flow, and    wherein the plurality of the louver wall surfaces ( 3   c ) include at least a louver wall surface ( 31   c ) displaced from the other louver wall surfaces ( 32   c ) in the direction (X 1 ) of the internal fluid flow and, as viewed from the direction (X 2 ) of the external fluid flow, the louver wall surface ( 31   c ) and the other louver wall surfaces ( 32   c ) are partially superposed one on the other.    
   
   
       4 . A heat exchanger according to  claim 3 , 
 wherein the plurality of the louver wall surfaces ( 3   c ) include at least a louver wall surface ( 31   c ) arranged alternately with the other louver wall surfaces ( 32   c ) along the direction (X 2 ) of the external fluid flow.    
   
   
       5 . A heat exchanger comprising: 
 a plurality of tubes ( 2 ) with an internal fluid flowing therein and stacked in the direction perpendicular to the direction (X 1 ) of the internal fluid flow; and    a plurality of fins ( 3 ) arranged between the tubes ( 2 ) to increase the heat transfer area in contact with an external fluid flowing between the tubes ( 2 ),    wherein the fins ( 3 ) have a plurality of flat portions ( 3   a ) substantially parallel to the direction (X 2 ) of the external fluid flow, and a plurality of louver wall surfaces ( 3   c ) twisted at a predetermined angle (θ1) to the flat portions ( 3   a ) are formed on the flat portions ( 3   a ) along the direction (X 2 ) of the external fluid flow, and    wherein a plurality of different louver pitches (LP1, LP2) are set.    
   
   
       6 . A heat exchanger according to  claim 5 , 
 wherein the short louver pitch (LP1) and the long louver pitch (LP2) are alternately set along the direction (X 2 ) of the external fluid flow.    
   
   
       7 . A heat exchanger according to  claim 1 , 
 wherein the fins ( 3 ) are corrugated and include a plurality of flat portions ( 3   a ), arranged along the direction (X 1 ) of the internal fluid flow, and a plurality of curved portions ( 3   b ) each connecting the adjacent flat portions ( 3   a ).