Tube heat exchanger with optimized thermo-hydraulic characteristics

Abstract

A tube heat exchanger comprising at least one tube extending along a certain axial direction, each tube being provided with heat exchange fins ( 4 ) spaced apart from one another along said axial direction and extending radially from said tube, each fins ( 4 ) being relief structured to form dimples and a groove/rib ( 5 ) arranged at a first distance from said tube, characterized in that said dimples ( 6 ) are placed on the outside of the groove/rib and arranged in at least one line surrounding the said groove/rib structure at a second distance from said tube greater than said first distance and in that said groove/rib ( 5 ) has a depth along said axial direction greater than the depth of said dimples ( 6 ).

1 . Tube heat exchanger ( 1 ) comprising at least one tube ( 2 ) extending along a certain axial direction (A), each tube ( 2 ) being provided with heat exchange fins ( 4 ) spaced apart from one another along said axial direction (A) and extending radially from said tube ( 2 ), each fin ( 4 ) being relief structured to form dimples and a groove/rib ( 5 ) arranged at a first distance (D 1 ) from said tube ( 2 ), characterized in that said dimples ( 6 ) are placed on the outside of the groove/rib and arranged in at least one line surrounding the said groove/rib structure at a second distance (D 2 ) from said tube ( 2 ) greater than said first distance (D 1 ) and in that said groove/rib ( 5 ) has a depth (P 1 ) along said axial direction (A) greater than the depth (P 2 ) of said dimples ( 6 ). 
     
     
         2 . Tube heat exchanger ( 1 ) according to  claim 1 , wherein said groove/rib ( 5 ) has a depth (P 1 ) between 0.6 and 1.6 mm and preferably between 0.8 and 1.4 mm, and said dimples ( 6 ) has a depth (P 2 ) between 0.4 and 1.4 mm and preferably between 0.6 and 1.2 mm. 
     
     
         3 . Tube heat exchanger ( 1 ) according to  claim 1 , wherein said fins ( 4 ) have a disc shape and are each provided with an annular groove/rib ( 5 ) and an annular line of dimples ( 6 ). 
     
     
         4 . Tube heat exchanger ( 1 ) according to  claim 1 , wherein said fins ( 4 ) have a helicoidal shape and are provided with a helicoidal groove/rib ( 5 ) and a helicoidal line of dimples ( 6 ). 
     
     
         5 . Tube heat exchanger ( 1 ) according to  claim 1 , wherein said dimples ( 6 ) have a shape chosen in the group comprising at least hemispherical, pyramidal, truncated shapes. 
     
     
         6 . Tube heat exchanger ( 1 ) according to  claim 1 , wherein in a certain axial plane (P), the width (L 1 ) of said groove/rib ( 5 ) is between 1.2 and 3.2 mm, the width (L 2 ) of said dimples ( 6 ) is between 1.2 and 2.4 mm and the pitch (D 3 ) between the middles of two adjacent dimples ( 6 ) is between 4 and 10 mm and preferably between 5 and 8 mm. 
     
     
         7 . Tube heat exchanger ( 1 ) according to  claim 1 , wherein in a certain axial plane (P), the distance (D 1 ) between said tube ( 2 ) and said groove/rib ( 5 ) is between 3 and 7 mm and preferably between 4 mm and 6 mm, and the distance (D 2 ) between said tube ( 2 ) and said dimples ( 6 ) is between 8.5 and 12.5 mm and preferably between 9.5 mm and 11.5 mm. 
     
     
         8 . Tube heat exchanger ( 1 ) according to  claim 1 , wherein said groove/rib ( 5 ) and said dimples ( 6 ) are arranged on both sides of said fin ( 4 ).