Numerical Study of Fuel Droplet Impact on Heated Surfaces Using Smoothed Particle Hydrodynamics Method 2019-01-0291

The impact of fuel droplets on heated surfaces is of great importance in internal combustion engines. In engine computational fluid dynamics (CFD) simulations, the drop-wall interaction is usually considered by using models derived from experimental data and correlations rather than direct simulations. This paper presented a numerical method based on smoothed particle hydrodynamics (SPH), which can directly simulate the impact process of fuel droplets impinging on solid surfaces. The SPH method is a Lagrangian meshfree particle method. It discretizes fluid into a number of SPH particles and governing equations of fluid into a set of particle equations. By solving the particle equations, the movement of particles can be obtained, which represents the fluid flows. The SPH method is able to simulate the large deformation and breakup of liquid drops without using additional interface tracking techniques. In order to consider the effects of evaporation due to high temperature, an evaporation model was developed, in the context of SPH formulation, to simulate the phase change process at the liquid-gas interface. A film boiling model was also developed to predict the interaction of liquid and solid surfaces at high temperatures. The present method can predict different outcomes of drop-wall interactions, such as spread, splash, breakup, rebound, and the Leidenfrost phenomenon. Based on the numerical results, preliminary criteria to predict the outcomes of drop-wall interaction were derived.