Effects of geometric structures on flow uniformity and pressure drop in dividing manifold systems with parallel pipe arrays

Dividing manifold systems have been extensively used in the areas of energy transfer and conservation. The design of uniform flow distribution is a critical issue for the enhancement of performance of the manifold system. In this study, the effects of the inlet Reynolds number and structural parameters (area ratio (AR), pipe pitch (Δl), height of convex head (hhead) and number of outlets (n)) on flow uniformity and pressure drop in the DMS-PPA have been numerically investigated and validated with experiment data. The non-uniform distribution in the manifold system has been quantified using the dimensionless parameter βi (flow ratio) and Φ (non-uniformity coefficient). The results indicate that the flow rate increases along the longitudinal direction of the manifold and becomes close to the average value in the 2nd and 3rd outlets. It is found that the Ф slightly drops with the Re rising, while the ΔPj would dramatically increase owing to the increasing inlet flow rates. The AR has the greatest influence on flow uniformity, and lower AR corresponds to a more uniform distribution. The corresponding Φ values increases from 0.00351 to 0.3885 when AR varies from 0.2844 to 4. Under the same inlet flow rate, the increase of n will lead to obvious flow non-uniformity. The superiority of flow performance in the DMS-PPA can be ascribed to the anti-parallel flow direction, and the 'plenum chamber-like' structure of the manifold. The optimsed geometric structures with 1 < AR < 1.5, and Δl=(ϕoi+ϕo(i+1)+120) mm are recommended, considering the synergetic effect of flow uniformity and pressure drop. This study can provide a reference for engineers in designing dividing manifold systems.