Geometrical Effects of Flow Reversers on the Thermo-Hydraulic Performance of a Rotating Horizontal Spiral Heat Exchanger

This research numerically evaluates the effects of various geometric parameters on the optimization of flow reversers on a rotating spiral heat exchanger utilizing computational fluid dynamics. There were three important geometric parameters investigated to find their impact on thermo-hydraulic characteristics: (i) distribution frequency of reversers along the spiral channel, (ii) reverser turn diameter, and (iii) reverser tube diameter. Thermo-hydraulic characteristics of the proposed designs were studied according to the velocity and temperature distributions, average Nusselt number, pressure drop, and performance evaluation criterion. From all the evaluated designs, the reduction in reverser tube diameter resulted in the most desirable performance as the average Nusselt number increased about 44.6% while the pressure drop increased merely by 10% compared to the base design. Thus, the obtained design gave the best performance evaluation criterion of around 1.77. Decrease in reverser turn diameter led to an increase in Nusselt number about 6.3%, although with 40% increase in pressure drop, resulting in the worst performance evaluation criterion of approximately 1.20. Overall, the results show that proper geometric optimization of flow reversers is able to noticeably enhance the thermo-hydraulic performance of the heat exchangers.