Flow performance evaluation and structural optimization of the dividing manifold systems using multi-attribute decision analysis

Abstract

Dividing manifold systems with parallel pipe arrays (DMS-PPA) are commonly used in building engineering for fluid transmission and distribution. However, it is often difficult to ensure a uniform flow distribution for each branch pipe in engineering applications, and the flow performance of manifold systems has seldom been evaluated considering both flow distribution and resistance characteristics. Therefore, this study aims to improve the flow performance and optimize the manifold configuration of the dividing manifold systems using a multi-attribute evaluation approach. The results show that the flow non-uniformity coefficient (Ф) and the dimensionless pressure drop (ΔPj/Ppref) indicator have an equivalent degree of influence on the flow distribution (minF=0.5×Φ+0.5×ΔPj/Ppref). The optimal design interval of the inlet/outlet area ratio (AR) for DMS-PPA is recommended as [1.4400, 1.7778] under the numbers of branch pipe N = 2, 3, 4, and 5. In addition, a novel spherical dividing manifold system with bifurcated pipe arrays (SDMS-BPA) was proposed for structural optimization, which can effectively improve flow performance under the condition of equal manifold volumes. The flow distribution uniformity has been improved by nearly 10 times compared to DMS-PPA when the branch pipe angle θ = 15°, spherical diameter ratio φmanifold, s/φin = 4.53, and the radius of spherical manifold l/R = 1. Despite introducing additional flow-turning losses, the total pressure drop in the system increased by approximately 25 %. This study provides an innovative solution and scientific guidance for achieving flow performance improvement and design optimization for dividing manifold systems in building engineering.