THE EXPERIMENTAL STUDY OF HEAT TRANSFER ENHANCEMENT AND PRESSURE DROP CHARACTERISTICS WITH WING-TYPE VORTEX GENERATORS FOR STAGGERED CIRCULAR TUBE BANK FIN COMPACT HEAT EXCHANGER

Compact heat exchangers are characterized by high heat duties per unit volume and high heat transfer coefficients. The heat enhancement of wing-type vortex generators (WVGs) with different heights, attack angles and distances between the fins were studied in this report. The staggered circular tube bank fin surface was investigated in detail by changing the angle of attack with θ = 25°,35°,45°, the height of wing-type vortex generators with H=6mm, 7mm, 8mm, the distance between the fins with Tp=6mm, 8mm, 10mm, the diameter of tube is 40mm. The result shows that the friction factor and Nusselt number increased with the increasing of attack angle, height of WVGs and distance of fins, but the Nusselt number does not change much with the attack angle. The WVGs have little heat enhancement to the tube surface; the WVGs have the influence to the other surface forming the channel. In the local mass/heat transfer study, the results show that the heat transfer reverse on the fin behind the tube can be avoided through WVGs.