Turbulence modification in gas–liquid and solid–liquid dispersed two-phase pipe flows

The ratio φ of the eddy viscosity induced by the dispersed phase to the shear-induced eddy viscosity was confirmed to be an appropriate parameter for correlating turbulence modification in gas–solid two-phase pipe flows in our previous study. The purpose of this study is to examine the applicability of φ to gas–liquid and solid–liquid two-phase dispersed upflows in vertical pipes. Experiments were, therefore, conducted under various conditions, in which liquid, gas and solid volumetric fluxes, particle diameter and pipe diameter were chosen as parameters. The velocities of continuous and dispersed phases and the phase fractions were measured by LDV and an image processing method. It was confirmed that measured turbulence modification is better correlated with φ than with the critical parameter proposed by Gore and Crowe. The critical point at which no modification occurs is close to φ=1, irrespective of the type of two-phase dispersed flow.