CFD simulation for flow distribution in manifolds of central-type compact parallel flow heat exchangers

This study numerically investigates the flow distribution of single-phase flow into central-type compact parallel heat exchanger through a cylindrical header having a circular cross section and circular tubes by using CFD (Computational fluid dynamics) simulations. Considering the interactive influence among geometrical parameters on their effect on the flow distribution, the influences of key geometrical parameters have been studied over a wide range such as the header diameter (50 mm < Dh < 200 mm), number of tubes (14 < N < 70), the inlet mass flow rate (2.662 kg/s < ṁ < 13.311 kg/s), the pitch between the tubes at the center (400 mm < Dpt < 800 mm) and the tube diameter (24 mm < Dt<44 mm). Besides, by analyzing the flow distribution, three types of flow distribution have been pointed out to help the designers to realize the interactive influence among geometrical parameters and decide the better design parameters faster. It can be concluded that for the type I distribution, the Dh should be increased and the Dpt should be decreased, for the type II distribution, the Dh should be decreased and the Dpt should be increased, for the type III distribution, the bigger the Dh and Dpt are, the more uniform the flow distribution is. Besides, the effect of AR (the flow area ratio) has also been investigated.