Investigations of thermohydraulic performance in heat exchanger tube with rectangular vortex generators

Abstract

To demonstrate the rationalization of multi-longitudinal swirls in heat exchanger tubes, this paper investigates the thermohydraulic performance of heat exchanger tube with rectangular vortex generator using numerical simulation. Comparative analyses of rectangular vortex generators and their different slotted structures are conducted, along with the investigation of the effect of the longitudinal pitch (P = 0.1 m, 0.2 m and 0.3 m) of the rectangular vortex generators on the thermohydraulic performance. The research reveals that the multi-longitudinal swirls induced by the vortex generator inside the tube accelerate the exchange of cold and hot fluids, improve the field synergies of velocity vectors and temperature gradients, and enhance the heat transfer efficiency of the heat exchanger tube. The slotted structure reduces the flow resistance and lowers the degree of disturbance to the fluid, which reduces the strength of the multi-longitudinal swirls, thus weakening the overall performance of the heat exchanger. The strength of the multi-longitudinal swirls has a direct influence on the overall performance of the heat exchanger tube. With the increase of P, the performance evaluation criteria (PEC) of the heat exchanger tubes decreases, and the maximum PEC = 1.44 is obtained for P = 100 mm at the studied Reynolds number range.