Heat-Transfer Device

Abstract

The invention includes a micro porous layer and a plurality of heat-transfer enhancing structures on a surface of the heat transfer tube in contact with the cold fluid. The heat-transfer enhancing structures have a height H that satisfies a relationship to a flow characteristic length D of 0.05>H/D≧0.01, and a relationship to an installation clearance L between the heat-transfer enhancing structures in a flow direction of 40<L/H≦300.

1 . A heat-transfer device including a heat transfer tube arranged inside a shell, the heat transfer tube being configured to allow a hot fluid to flow inside thereof and a cold fluid to flow outside thereof for heat exchange through convective heat transfer, the device comprising a micro porous layer and a plurality of heat-transfer enhancing structures on a surface of the heat transfer tube, the surface being in contact with the cold fluid, wherein the heat-transfer enhancing structures have a height H that satisfies a relationship to a flow characteristic length D of 0.05>H/D≧0.01, and a relationship to an installation clearance L between the heat-transfer enhancing structures in a flow direction of 40<L/H≦300. 
     
     
         2 . The heat-transfer device according to  claim 1 , wherein each of the heat-transfer enhancing structures is secured at both ends to an inner surface of the shell. 
     
     
         3 . The heat-transfer device according to  claim 1 , wherein the micro porous layer has asperities thereon with an average height not more than 10 μm.