Heat and mass transfer in melt and porous material
The quality of given product essentially depends in metalurgy. The necessary constitution of material can be obtaied by doping. The homogenity of doping elements depends on various factors such as:
- their physical and chemical properties;
- form of fluxes;
- the distribution of temperature in melt.
Principially different conditions for homogenity can arise in various methalurgical equipments, because of their geometrical shape and regions of heating and adding of doping elements. Various vortexes are characteristic for the flux of melt, and the structure of flux is turbulent. Hence, the analysis of transfer processes is complicated. Moreover, the possibilities of experiments in real conditions are limited. Therefore, it is necessary to make
- investigations of temperature and fluxes in model equipments;
- mathematical models of transfer processes.
The laboratory has an expieriency in such kind of model-experiments and numerical 2D, 3D simulations. On basis of 2D k-e model for turbulence, a new approach is made that allows to include the macroscopic pulsations of flux. Therefore, the results well coincides with experiment data. The investigations allows to predict heat and mass transfer processesin various kinds of metalurgical equipments (crucible and channel furnaces, thermal furnaces of ore, etc.).
The lifetime of metalurgical equipment and its efficiency depends essentially on
- diffusion of metal vapour and infiltration of vapour in porous refractory;
- deposition of metal oxides on porous material contacting with melt.
Thus, we need to investigate the diffusion, infiltration, phase transition that determines accumulation of metal in pores and on surface. For this reason mathematical model is made using the principles of physical kinetics, diffusion and filtration, and hydrodynamics. The model can describe the processes in porous material and the visinity of surface. The original software is made on the basis of the model. The model is examined by carrying out experiments with induction melting furnace with high frequency.
Basing on this approach, the deposition of oxides is investigated, e.g., from steel and aluminium melts, and also zinc accumulation in pores of ceramics from brass and steal melts. The numerical simulations show the dynamics depending on essential parameters (temperature, properties of doping elements and porous material, inetnsity of flux, etc.). The obtained results explains the situations occured in praxis and coincides with practical observations.