Research on Wave Phenomena in Hydraulic lines : 1st Report, Unstteady Liquid Flow in a Uniform Pipe

Abstract

Three sorts of wave equations, i.e., (i) wave equations taking into account viscosity and radial velocity, (ii) wave equations assuming Hagen-Foiseuille flow and (iii) water hammer equations, are compared for unsteady flow in uniform lines. Both frequency and transient response experiments are carried out with use of a rotary sinusoidal flow generator and a quick closing valve, respectively. Experimental and numerical results make clear that the wave equations (i) can most accurately predict wave phenomena in hydraulio lines. The wave equations (ii) and (iii) are found to be applicable to sinusoidal excitations for the ranges of α²ω/ν<1.7 and α²ω/ν>4600, respectively. By utilizing "numerical inversion of the Laplase transform", transient responses can be calculated. Sample experimentations show that the procedure is considerably simpler and correcter than existing methods.