The significance of drop non-sphericity in sprays

Abstract

This paper presents a new framework to model drop dynamics in Lagrangian sprays. The framework builds on the Taylor Analogy Breakup (TAB) model. Real-fluid (gas-liquid) thermodynamics applicable to multicomponent systems are combined with Gradient Theory to facilitate detailed calculations of drop surface tension forces, oscillations, and breakup processes. This is combined with a more detailed treatment of deforming drop dynamics to construct more accurate representations of the local interfacial exchanges of mass, momentum, and energy. The framework is derived using an energy balance equation that explicitly enforces drop momentum conservation during the breakup process. This facilitates development of a refined set of drop equations that address current shortcomings in the prediction of drop properties over a wide range of relevant breakup conditions. The resulting drag forces, evaporation, and heating rates deviate significantly from the predictions given by contemporary drop models used in modern simulations. These deviations are quantified using Large Eddy Simulation (LES) with a Lagrangian-Eulerian modeling approach. The analysis demonstrates how the model improvements in the new framework provides a more detailed representation of physical complexities that are largely neglected in modern studies.