Study On Direct Numerical Computation Of Droplet Impacting Wall Problem By SPH: Heat Transfer Analysis Between Droplet And Wall

The phenomenon of drop collisions with surface exists widely in nature and modern industry.The hydrodynamics and heat transfer problems involved in this phenomenon have attracted many researchers' interest.This paper mainly studies the heat transfer process between droplet and wall,which has important guiding significance for fuel atomization of engine,and lays a theoretical foundation for improving fuel utilization rate and reducing pollutant emissions.In this paper,the numerical simulation is used to study the heat transfer between the single droplet and the surface.The main work and conclusions are as follows:Firstly,SPH method is used to simulate the movement phase and the spreading phase of the collision between the droplet and the wall.The heat flux of the droplet and the cumulative heat transferred from the wall to the droplet are taken as the detection parameters.Comparing the simulation results with Batzdorf's calculation results,it is shown that there is a good agreement between the two without considering the influence of evaporation and density,which verifies the availability of the model.Then,the mechanism of heat transfer between droplet and wall is analyzed and the distribution law of temperature and heat flux inside the droplet is revealed.The influence of initial parameters on the heat transfer between the droplet and the wall is studied.The simulation results show that the larger the initial velocity of droplets,the smaller the viscosity coefficient,the more obvious the change of droplet temperature and heat flux density,And the initial velocity has more influence than the viscosity coefficient.Finally,the actual production is guided by the research results in this paper.In the engine,increasing the fuel injection speed can improve fuel efficiency and reduce emissions.In the3 D droplet printing technology,increasing the initial velocity of the metal droplets and choosing the metal material with a smaller coefficient of viscosity can increase the passing rate of products.And the coffee ring effect is explained by this study.