0D Homogeneous Simulation of Droplet Size Evolution in a Turbulent Stirred Tank

Abstract

Zero-dimensional (0D) homogeneous simulations with a novel breakup kernel were performed to predict droplet size evolutions in a turbulent stirred tank. The 0D homogeneous method takes account of the heterogeneous mixing by introducing the distribution of the turbulent energy dissipation rate but avoids intensive computations by the weak coupling between the population balance model and computational fluid dynamics. To validate the applicability of the method, time scales of the turbulent mixing and droplet breakup were analyzed. Results indicated that turbulent mixing is much faster than droplet breakup in the stirred tank, indicating that the prerequisite for the application of the 0D homogeneous method can be satisfied. Furthermore, appropriate simulation strategies were determined by analyzing the influence of the computational parameters on the predicted droplet size distributions (DSDs). Based on this, DSDs under various dispersed-phase viscosities were calculated and compared with the experimental results in the literature (Wang, C. Y.; Calabrese, R. V. AIChE J. 1986, 32, 667). The method constructed in this work was found to be general to low dispersed-phase viscosities.