Relaxation Models for Wave Phenomena in Liquid-Vapor Bubble Flow in Channels

Abstract

We examine wave characteristics of a liquid-vapor mixture in order to investigate certain features of the homogeneous relaxation model. The model is described by one-dimensional averaged mass, momentum, energy equations, and a rate equation. Since the homogeneous relaxation model delivers a qualitative incompatibility of numerical and experiment results of large wave propagation, it is extended so as to take into account the heat conduction in the liquid surrounding vapor bubbles. With this extension, the effects of spreading and damping of the waves in the numerical solutions are similar to those observed in the experiment. Thus, a new model is created, the homogeneous relaxation-diffusion model which contains two physical quantities—the relaxation time and macroscopic heat conduction coefficient. Both quantities are determined based on experimental data. It seems that the results obtained from the new model agree well qualitatively with the experiments.