Study of Compressible High Speed Gas Flow in Piping System : 2nd Report, Piping Systems with Sudden Enlargement

Abstract

Flow characteristics of piping systems with sudden enlargement at high subsonic region is studied in this in this report. Experiments are carried out with the area ratio as well as the flow Mach number varied. The effect of a change in the face pressure on loss characteristics is studied, and the following empirical formulas are obtained P_f/P₁=1.0-M₁^β, where P_f denotes the pressure at the face of the step, and the subscript 1 refers to the inlet value of the enlarged section, and α, β are constants dependent on the area ratio of enlarged parts. Flow patterns around the sudden enlargement parts are visualized applying the Schlieren method and the flow asymmetry or vibration down-stream of the enlarged part is discussed. Finally, a practical method of computing flow losses of high speed piping system is described.