Numerical investigation of thermohydraulic performance on wake region in finned tube heat exchanger with section-streamlined tube

Abstract

This paper proposes the section-streamlined tubes to explore the effect of wake region on thermohydraulic performance in the finned tube heat exchangers. Tube configurations and the angle θ have been numerically investigated. Firstly, simulation by k-ω has been validated by Arafat's simulation and experimental results. It shows good agreement by 7.78% j factor and 6.4% f factor. Then two groups of numerical simulations have been done to research the effect of heat transfer tube on thermohydraulic performance. One of them is focused on the effect of different geometry configurations (circle tube, ellipse tube, rhombic tube, hexagon tube and fusiform tube). It can be concluded that wake region has negative influence both on the heat transfer performance and the flow characteristics behavior, and the section-streamlined tubes can improve the overall performance. The other one is aimed at the effect of rhombic tube and hexagon tube with different angles ( θ = 40°, θ = 60°, θ = 80°). The results show that separation angle has great influence on the formation of wake region due to the fluid inertia. Besides, the angle θ has great positive influence on the comprehensive performance. On the whole, the hexagon tube in the finned tube heat exchanger with the angle θ of 40°, which has 19.4% higher j factor and 12.4% lower f factor, eventually resulting 24.8% higher JF factor than the circle tube, has the best performance. • Circle tube, ellipse tube, rhombic tube, hexagon tube and fusiform tube have been investigated. • Rhombic tube and hexagon tube with different angles are studied to analyze the effect of wake region behind tube on thermohydraulic performance. • The influence of fluid inertia on the separation angle and the formation of wake region has been analyzed.