A conservative framework for primary atomization computation and application to the study of nozzle and density ratio effects

The present work focuses on the application of two recent developments of the volume-of-fluid method to the computational study of primary atomization: a second-order unsplit volume-of-fluid algorithm and a conservative monotonicity preserving discretization of the two-phase Navier-Stokes equations. This novel combination is motivated in the context of primary atomization at arbitrary density ratios. A validation of this framework is first carried in a controlled yet complex numerical experiment, a turbulent two-phase temporal jet. An analysis of the conservation errors and the convergence of the drop-size distribution under grid refinement is provided, and was found to substantiate the ability of the method to resolve small droplets. Finally, a comparison of the performances of a simplified yet realistic injector with the breakup resulting from a fully turbulent cylindrical pipe in similar conditions is provided for varying density ratios (40 and 800). The framework is shown to be able to yield quantitative trends regarding the atomizer performances.