Eulerian multiphase model of fragmenting flows

Fragmentation of liquids is widely applied in many industrial and agricultural applications to increase efficiency of reaction and evaporation processes. In these applications, the mean particle size and the particle size distribution play an important role. In particular, in combustion applications, the presence of excessively large drops or small drops has an adverse effect on the system performance in terms of the exhaust pollutants. In addition droplet evaporation is an essential physical process in creating a fuel and oxidizer mixture. In order to gain a fundamental understanding of the underlying physics, it is necessary to develop generalized numerical models that describe the fragmentation and evaporation phenomena occurring simultaneously.;The current work proposed a multiphase model coupled with the population balance methodology to predict the spatial evolution of particle size distribution alongside such other physical processes as evaporation and transport. The advantage in this model lies in the fact that it requires only two user-defined parameters namely, the breakage frequency constant and a breakage kernel parameter to model the mean particle size and particle size distribution, which can be obtained from empirical data. The applicability of this model was tested on two different atomizers with different geometries and with different flow variables. From comparing the results from these simulations with experimental data, it can be concluded that this model is able to predict various spray parameters such as axial volume flux, mean particle size, and local particle size distribution. In addition two different methodologies of incorporating drop evaporation alongside the aforementioned fragmentation model are proposed. The combined fragmentation and evaporation model is exercised for the case of a slug flow in a pipe to demonstrate the competition between these two physical processes.