Advances in Compound Techniques (Fourth Generation Heat Transfer Technology)

Experimental analysis of forced convective heat transfer of nitrate salt in a spirally grooved tube at high Reynolds numbers and temperatures

“…Passive methods to enhance the forced convective heat transfer in a tube have been employed in various industrial fields such as desalination or power plant condensers and have been widely investigated in the literature [10] . Two main passive approaches can be distinguished: 1) Methods implying the deformation of the tube (rough surfaces or extended surfaces trough transverse or helical ribs or fins); 2) insertion of structures into the tube that disturb the fluid flow (displaced enhancement devices or swirl flow devices, such as twisted tapes or wire coils) [ 11 ]. The main idea behind these approaches is the disturbance of the existing boundary layer, increase of heat transfer area, increased turbulence of the flow or a combination of all three, which leads to an increased heat-transfer performance.…”

“…The main idea behind these approaches is the disturbance of the existing boundary layer, increase of heat transfer area, increased turbulence of the flow or a combination of all three, which leads to an increased heat-transfer performance. The most successful technique, mainly because of its effectiveness and simplicity in application, has been augmentation through surface roughness [ 11 ]. Here the surface roughness of the tube is increased by forming repeated grooves in the tube.…”