Study On Direct Numerical Simulation Method Of Droplet Collision Wall Problem

The phenomenon of free surface flow is widely found in our life and industrial technology.There is a strong mass heat exchange process in the phenomenon of droplet collision thermal wall surface,which involves many fields such as chemical industry and metallurgy.Studying the process of droplet collision hot wall,the distribution of heat flux density on the wall and its influence on the heat transfer process are of great guiding significance for improving the quality of drip printing molding and reducing the pollution gas emission by improving the quality of fuel atomization of internal combustion engine.Taking the heat transfer mechanism in the process of droplet collision hot wall as the research focus,this paper combines the numerical simulation idea of smooth particle fluid dynamics method with the experimental method,and the concrete work is as follows:First of all,this paper expounds the basic principle of SPH method from the theoretical aspect,and deduces the basic equation.The smooth function is constructed by the smooth function construction method,and the applicability analysis of the smooth function used in this paper is carried out,and the fluid control equation in Lagrange form,which adheres to the three laws of mass conservation,momentum conservation and energy conservation,is obtained,and the control equation is discretized.The thermodynamic model of this paper is put forward,the SPH method is combined with the heat conduction equation,and the control equation suitable for the research content in this paper is deduced,and the thermal conductivity discrete heat conduction equation is obtained.Secondly,according to the research content of this paper,this paper expounds the programming process,and designs the SPH method,including the design of initialization program,main program and parallel program.Then,through the SPH method program to simulate the dynamic process and heat conduction process of droplet collision hot wall,the applicability and convergence of this model in the dynamic research process are verified by analyzing the internal pressure and density of droplets.By analyzing the change of heat transfer process and heat flux density inside the droplet,the change of temperature field and the distribution law of heat flux density inside the droplet are demonstrated.By calculating the Rayleigh-Taylor instability example,the rationality of the numerical calculation in this paper is verified.Finally,by changing the Weber number and wall temperature of droplets,the influence of Weber number,wall temperature and droplet spreading diameter on the heat transfer process of droplet collision thermal wall is analyzed,and the influence of Weber number and wall temperature on two droplet generation is discussed.The results show that the larger the number of Weber,the greater the wall temperature,the greater the heat transfer of droplets,the heat transmission intensity of droplets and wall is affected by two droplets;the larger the number of Weber,the greater the wall temperature,the more two droplets are generated.