Numerical simulation of cooling of fine metal powder in various gaseous environment

Abstract

The article discusses the dispersion of metal powders in a plasma installation, and the cooling of metal particles in various gaseous environment such as argon, helium and their mixtures. The main interest in this study is the trajectory, flight range, the rate of crystallization and cooling of the obtained particles. The data obtained during this investigation are necessary for the development and creation of full-fledged plasma equipment. In order to calculate the distribution of the flow velocity and temperature when modeling the process, it is necessary to carry out an analysis of the conditions for the formation of spherical metal powders under the action of plasma jets on the basis of the accepted concept of the physical and thermal model of the arc. To obtain the non-stationary mathematical models correctly, it is also necessary to know the geometric characteristics of the plasma installation, the flow rate of the plasma-forming gas, the electromagnetic parameters of the arc, the composition and the properties of the molten metal, and a number of other factors. Initially, the problem of choosing of a plasma-forming and technical gas to fill the working chamber of a plasma installation was solved. The properties of gases were calculated, which are necessary for further mathematical modeling of the physical processes of interaction of metal particles with the gaseous environment of the working chamber. On the basis of the results of mathematical modeling of particle cooling, it can be unambiguously concluded that a gas environment with a predominance of helium is the most effective option for filling the process chamber, which serves to cool and collect the resulting metal powder, because cooling occurs 4 times faster than in argon.