Acoustic Wave Propagation In Bubbly Liquids With Vapor/Gas Bubbles

The research of the propagation of acoustic wave in vapor/gas bubbly liquids has important theoretical and practical significance,such as improving the rate of chemical reaction and optimizing the structure of reactor.The non-condensing gas dissolved in liquid form vapor/gas mixing bubble with vapor in which oscillation characteristic changes the inherent property of the liquid,affecting the wave velocity and dissipation of acoustic wave propagation.Due of the complexity of phase change in the vapor/gas-liquid multiphase flow,the propagation of acoustic waves in complex flow has not been solved systematically.The propagation of acoustic waves in vapor/gas bubbly liquids is employed in this paper.The main contents are as follows:Firstly,three regions of acoustic wave speed in vapor/gas bubbly liquids are put off according to the characteristics of wave speed with frequency,separated by high and low frequency cut-off frequency.In "region 2",the oscillation of wave speed is violent,while the variation of wave speed in "region 1" and "region 3" can be regarded as fixed values,which are expressed by high and low frequency constant wave speed respectively.Then the influence of two cut-off frequencies and constant wave speeds are analyzed and discussed.It is found that the high frequency constant wave speed is constant,which is the value of wave speed in pure liquid.Void fraction,mixing bubble radius and vapor mass fraction affect the two cut-off frequencies and the low frequency constant wave speed with varying degrees.Secondly,the minimum speed of acoustic wave propagation in vapor/gas bubbly liquid is studied.The behavior of acoustic propagation is divided into two categories according to the location of minimum wave speed.With the boundary of critical vapor mass fraction,when vapor mass fraction is large,minimum wave speed is near the resonant frequency region;on the contrary,minimum wave speed exists in the low frequency region.The effects of important parameters(void fraction,mixing bubble radius and vapor mass fraction)on minimum wave speed and critical vapor mass fraction are discussed in detail.