In the present paper mathematical model of the deformation behavior of a liquid spherical particle upon its impingement onto a solid surface, including flattening and simultaneous solidification is developed. Particle-substrate interactions are investigated for typical thermal spray process. Numerical simulation for the complete Navier-Stokes equations is based on the finite-difference method on rectangular mesh in cylindrical coordinates. The energy equation is solved for both particle and substrate regions using the adjoint conditions for the temperature. In this paper main attention is paid to investigation of the temperature in contact of the particle with substrate. In connection with the oxide films effect on the surface substrate taking onto account thermal resistance of oxide is simulated. Heat transfer process in particle and substrate has been modeled by 2-D problem of heat conduction with influencing hydrodynamic processes into molten particle. Particle solidification and the movement of the solidification front have been described by means of one-dimensional Stefan problem. Numerical results for the heat transfer process and the effect of some important processing parameters such as particle diameter, viscosity, oxide films and temperature of plasma on the flattening and solidification of a single liquid particle have been discussed. Numerical algorithms were realized in the form of applied programs complex.

In this paper, the flattening and the simultaneous solidification of a liquid particle when it hits a solid surface are described mathematically and numerically simulated in cylindrical coordinates on the basis of the Navier-Stokes equations. The heat transfer in the particle and in the substrate is simulated by solving the 2-D heat conduction problem, whereby hydrodynamic processes in the melted particle as well as pressure forces are taken into account. The particle solidification is investigated using the one-dimensional Stefan problem, taking into account the contact heat conduction at the boundary between particle and substrate. For numerical calculations, computational algorithms were created on the basis of the difference method, which were implemented in the form of an applied program complex. Paper includes a German-language abstract.

This paper presents a mathematical model of the plasma-spray coating formation process that allows one to estimate bond strength energy, a parameter related to coating quality. Bond strength energy is defined on the basis of particle-substrate or system balance. Unknown quantities in the energy equation are obtained from nonstationary Navier-Stokes equations for velocity field and pressure and from thermoelasticity equations for temperature and stress. Complexities associated with particle spreading and nonlinear hydrodynamics have made it necessary to develop a stable numerical technique.