Heat exchanger for a high inflow velocity

Abstract

The invention relates to a heat exchanger for cooling a hot fluid, namely an exhaust gas or a fuel-cell cooling fluid, by means of a cooling fluid which is at a lower temperature than the hot fluid and which has a high flow velocity, comprising a high-temperature grille for guiding the hot fluid and a low-temperature grille for guiding the cooling fluid. According to the invention, a heat exchanger which can improve a transfer of heat despite a high-velocity inflowing fluid and/or which can reduce the required installation space is created in that a diffuser region for decelerating the cooling fluid is arranged in at least one first low-temperature channel, through which the cooling fluid flows, of the low-temperature grille, and in that the diffuser region and a first high-temperature channel, through which the hot fluid flows, of the high-temperature grille have at least one shared wall for heat transfer.

1 . A heat exchanger for cooling an exhaust gas or a fuel-cell cooling fluid, by a cooling fluid which is at a lower temperature than the hot fluid and which has a high flow velocity, comprising:
 a high-temperature grille for guiding the hot fluid,   a low temperature grille for guiding the cooling fluid, and   wherein, in at least one of the low-temperature channels of the low-temperature grille through which the cooling fluid flows, a diffusor region is arranged to slow down the cooling fluid, and   wherein the diffusor region and a first high-temperature channel of the high-temperature grille through which the hot fluid flows has at least one common wall for heat transfer.   
     
     
         2 . The heat exchanger according to  claim 1 , wherein the at least one common wall for forming the diffuser range in the first low-temperature channel has a first planar or convexly curved diffuser section. 
     
     
         3 . The heat exchanger according to  claim 1 , further wherein the low-temperature channel has a deflection region which is arranged upstream of the diffuser region and in which the cooling fluid is deflected but still not slowed down, is accelerated. 
     
     
         4 . The heat exchanger according to  claim 1 , wherein, in the low-temperature channel a second common wall is arranged opposite the first common wall, which, on the wall side facing away from the first low-temperature channel adjoins a second high-temperature channel of the high-temperature grille in the diffuser region, wherein the second common wall in the diffuser region has a planar or concavely curved diffuser section. 
     
     
         5 . The heat exchanger according to  claim 1 , wherein an inlet for diverting the cooling fluid into the diffuser region is arranged in front of the diffuser region in the flow direction of the cooling fluid. 
     
     
         6 . The heat exchanger according to  claim 1 , wherein downstream of the diffuser region is a discharge region with a discharge nozzle for accelerating the cooling fluid. 
     
     
         7 . A heat exchanger arrangement with a heat exchanger according to  claim 1 , comprising a flow channel for the inflow of the cooling fluid to the heat exchanger, wherein the heat exchanger is arranged in the flow channel for guiding the cooling fluid, and
 wherein the low-temperature grille and the high-temperature grille form a first heat exchanger module of the heat exchanger,   wherein a plurality of common walls together form a first inflow surface in the flow channel which borders the first heat exchanger module and is spanned by the common walls, wherein the inflow surface has a flow angle between 0° and 45°, advantageously between 3° and 15°, to a main channel direction of the flow channel.   
     
     
         8 . The heat exchanger arrangement according to  claim 7 , wherein a main region of the low-temperature channel with an extension axis adjoins the diffuser region downstream, in particular directly, and wherein the direction of the extension axis, a direction of a wall extension of the common wall in the main region, forms a main slope angle between 0° and 60°, between 30° and 55°, to the inflow surface of the heat exchanger. 
     
     
         9 . The heat exchanger arrangement according to  claim 7 , wherein a plurality of common walls together form a first outflow surface in the flow channel which delimits the first heat exchanger module and is spanned by the common walls and borders it downstream, wherein the first outflow surface forms a first outflow angle between 0° and 45° to a main channel direction in the flow channel. 
     
     
         10 . The heat exchanger arrangement according to  claim 7 , wherein the heat exchanger is configured and arranged from the first heat exchanger module and an additional second heat exchanger module, wherein a further plurality of low-temperature channels and high-temperature channels form the second heat exchanger module and wherein a further plurality of common walls together form a second inflow surface in the flow channel which borders the second heat exchanger module and is spanned by the common walls, wherein the second inflow surface provides a second inflow angle between 0° and −45°, to a main channel direction of the flow channel. 
     
     
         11 . The heat exchanger arrangement according to  claim 10 , wherein the additional plurality of common walls together provide a second outflow surface in the flow channel which borders the second heat exchanger module upstream, wherein the second outflow surface forms provides a second outflow angle between 0° and 45° to a main channel direction of the flow channel. 
     
     
         12 . The heat exchanger arrangement according to  claim 10 , wherein the first heat exchanger module and the second heat exchanger module are designed configured and arranged to be surface-symmetrical to a common reflector surface lying between the first and second heat exchanger modules, which runs parallel to a main channel direction of the flow channel. 
     
     
         13 . The heat exchanger arrangement according to  claim 7 , wherein a part of the flow channel provides a cold channel traversing past the heat exchanger. 
     
     
         14 . A turbomachine comprising a bypass channel and a heat exchanger arrangement according to  claim 7 , wherein the flow channel is a bypass channel and the low-temperature grille is in fluid connection with the bypass channel and/or the high-temperature grille is in fluid connection with the main flow channel. 
     
     
         15 . The turbomachine according to  claim 14 , wherein a plurality of heat exchanger arrangements are distributed in the circumferential direction in the bypass channel.