燃油喷雾撞壁与油膜蒸发特性研究

A one-dimensional non-stationary spray impinging model was constructed. Several key factors like droplet evaporation, fuel film spreading and fuel film surface temperature were considered in this model. For fuel spray impingement, staged modeling was used. In the free penetration stage, the spray was described using a liquid phase penetration length prediction model and droplet evaporation model, then the impingement moment was determined. In the spray impingement stage, the spray was simplified to the spray impingement process of the micro-element droplets. Coupling the droplet evaporation model, the fuel film surface temperature model and the fuel film evaporation model, a one-dimensional unsteady normalized model was constructed to predict the fuel film across the spray impingement stage, the fuel film spreading stage and the fuel film evaporation stage with spreading radius of the fuel film as the characteristic parameter. The results show that the staged and discretized one-dimensional unsteady impingement spray model can accurately predict the spray penetration, near-wall spreading, fuel adhesion and evaporation processes under a wide range of ambient temperatures. It is found that increasing the ambient temperature and decreasing the ambient pressure can increase the maximum temperature of the fuel film surface and accelerate the evaporation rate of the fuel film.