Investigation of flow distribution and geometric parameter optimization in continuous manifold systems under unsteady flow conditions

Continuous manifold systems (CMS) are widely used for energy and mass transfer. The flow distribution of the branch ports directly affects the flow pattern of the chamber. However, the current understanding of the flow distribution in CMS under unsteady flow conditions and the optimization of their geometry is still limited. In this study, three-dimensional numerical simulations were performed to investigate the flow distribution of branch ports under unsteady flow conditions. Moreover, this study analyzed the effects of the geometric parameters of CMS on the non-uniformity coefficient (α) and total pressure drop (ΔP) under the maximum inlet flow condition (Q = 23.40 L/s). The results show that (i) from 0 to 12 s, the flow ratio (β) at the branch ports decreases in the direction of the fluid flow and then increases in the same direction from 12 to 90 s; (ii) as flow growth coefficient (η) increases, α for the maximum inlet Reynolds number (Re) increases slightly, and the difference in α corresponding to the same Re at different time points decreases; (iii) the increase in area ratio (AR) causes the flow rate of the first branch port to rise and the flow of the terminal branch port to decrease. The value of α increases linearly with AR: α = 0.23AR−0.11; (iv) The most economical approach involves adopting a linearly tapered branch ports width design with b1/b10 = 1.50, which decreases α by 65.04% while increasing the ΔP by 9.93% compared to the original design. This study can provide a reference for engineers in designing CMS with unsteady flow.