Significance of Truckenbrodt's Energy and Momentum Coefficients for Loss Calculation in Ramified Pipe Systems

Abstract

For one-dimensional simulation of flow in ramified pipe systems loss prediction in junctions is essential. In the standard literature (e.g.[1]) total pressure loss coefficients serve this purpose. Elementary formulas follow from the principle of momentum and some simple assumptions [2]. They yield rather crude estimates, often twice as large as experimental values. Modifications described by Idelchik [3] look nice, but after all turn out to be not more accurate. We explain deviations and propose improved loss formula based on Truckenbrodt's energy and momentum coefficients [4], thus paying regard to velocity distributions over pipe cross-sections. We further discuss extraction of the coefficient's values from experiments.