AIChE Journal, Vol.41, No.1, 12-22, 1995
Phenomenological Model for Dispersed Bubbly Flow in Pipes
An analytical approach to the problem of steady-state, axisymmetrically dispersed, bubbly flow in pipes based on a zero equation turbulence model is discussed. The formulation incorporates recent experimental observations and introduces the effect of bubble size in a rudimentary way. The two-phase mixture is modeled as a variable-density single fluid assuming an empirical void distribution family. The turbulent shear stress is formed from the contributions of both the velocity and density variation, and the solution of the resulting Reynolds-type equation yields the velocity profile of the flow. Predicted void fraction and velocity distributions agree well with experimental measurements. The main objective of the model is to predict the friction multiplier with minimal computational effort. The velocity profiles of this model agree reasonably well with experiments. Predictions for the friction multiplier are compared to six known and widely used correlations, as well as to experimental data. All the correlations severely underpredict the friction multiplier in the dispersed bubbly flow regime, while the results of our model agree well with the measurements, within the range of its validity.