Prediction model and energy dissipation analysis of Taylor bubble rise velocity in yield stress fluid

In this study, a velocity field model around a Taylor bubble is established after the analysis of the disturbed region around the bubble. The model combines the continuity and yield stress fluid constitutive equations. Based on this velocity field model, an energy dissipation model for the work accomplished by each resistance of bubbles is proposed. In addition, based on an analysis of energy conservation, a new model for predicting the velocity of a Taylor bubble in a yield stress fluid is presented. The experiments of Taylor bubble through Carbopol solution migration in 50 and 60 mm diameter tubes were carried out. Results show that the yield stress has considerable influence on the rise speed of the bubble, improving the anti-disturbance ability of the fluid and further stabilizing the tail of the bubble. Combined with experimental data, the bubble velocity prediction model is verified, and the error value of the calculation result is found to be less than 6%. An energy analysis of the Taylor bubble rising process shows that the volume of the bubble increases, the proportion of work done by inertial force and surface tension decreases, and that done by viscosity force and yield stress increases. The work done by surface tension has little effect on the rise speed of bubbles, which can be ignored. The Taylor bubble velocity changes slightly with the volume, as the bubble volume increases, and the buoyancy work is consumed by the viscous and inertial forces in the film region.