Droplet collision and coalescence model and its application in the spray combustion simulation

Due to the fact that the droplet collision and coalescence model is very important and the models existed are time-consuming and mesh-dependent. Based on the principal idea of smooth particle hydrodynamics method, a new droplet collision and coalescence model was presented. The model assumes that a droplet can only collide with a given number of nearest droplets surrounding it. In this way the droplet collision probability was redefined. Numerical simulation shows that the model presented is mesh independent, highly efficient and accurate. Then Euler-Lagrangian method including droplet deformation, breakup and phase change, coupled with finite rate chemical reaction model was used and three dimensional turbulent spray combustion simulation was carried on the eject mode of RBCC. Comparison was made between computation and the experimental data and it is shown that in the eject mode of RBCC, the movement of injector downstream to some extent can increase the fuel combustion efficiency and thrust.