Manifold Flow in Pressure-Distribution Systems

Abstract

Manifolds are used extensively in pipeline engineering applications. They may be classified as combining-flow in which the flow rate increases along the length of the manifold, and dividing-flow in which the flow rate decreases along the manifold length. The present paper addresses dividing-flow manifolds with the emphasis on pressure-distribution systems. The seminal theoretical and experimental work of McNown on discrete tee takeoffs, applicable to pressure-distribution-system manifolds, is discussed and elaborated upon for flow across the run of the tee and into the tee branch. Pertinent theoretical and experimental work for discrete orifice takeoffs is summarized. The information thus presented facilitates discussion of certain concepts presently incorporated in pressure-distribution-system design. Certain erroneous concepts are identified. A perspective is provided and improvements in related aspects of manifold design are suggested. A separate paper, presented at the ASCE/EWRI World Environmental and Water Resources Congress 2010 Conference, builds on the present paper by specifically addressing wastewater pressure-distribution systems.