Dynamics of drop breakup in inhomogeneous turbulence at various volume fractions

Abstract

We report experimental and numerical determinations of the breakup probability of a drop travelling through inhomogeneous turbulent flow generated in a pipe downstream of a restriction. The model couples the Rayleigh–Lamb theory of drop oscillations with the Kolmogorov–Hinze theory of turbulent breakup. The interface deformation is modelled by a linear oscillator forced by the Lagrangian turbulent Weber number measured in experiments. The interface is assumed to rupture when either (i) the instantaneous Weber number exceeds a critical value or (ii) the predicted deformation exceeds a given threshold. Seven flow configurations have been tested, corresponding to various Reynolds numbers, damping coefficients and drop volume fractions. The history of the drop deformation proves to play an important role, and simulations assuming a critical Weber number fail to reproduce the experiments. Simulations assuming a critical deformation predict well the main features observed in the experiments. The linear oscillator appears able to describe the main feature of the dynamics of the drop deformation in inhomogeneous turbulence. Provided the oscillation frequency and the damping rate are known, the model can be used to compute the breakup probability in concentrated dispersed two-phase flows.