Modeling of Processes of Heating and Cooling of Materials in a Solar Furnace

Resumo

The processes of heating and melting of materials in a concentrated high-density solar flux at the Large Solar Furnace are studied. The possibilities of calculating the rate of heating and cooling of molten materials are shown using the example of pyroxene rocks exposed to concentrated solar radiation. The influence of the main technological factors (the heating rate of the substance to the melting point and above, as well as the cooling rate) on the quality of the melt is studied. The equation of heating due to the absorption of solar radiation is constructed taking into account convective heat transfer and heat loss due to thermal radiation. The melt cooling process is described by the Newton–Richmann law taking into account thermal conductivity, convection, and radiation. Three different types of cooling of the melt at different rates were implemented. It is shown that by choosing the melt cooling method, various cooling rates can be achieved: 10², 10³, and 10⁴ K/s. The dependences of the grain size of the material on the cooling rate were obtained. The dependences of the microstructure of the material obtained from the cooled melt on the cooling rate of the melt were analyzed. It is shown that, within the context of the model, taking into account assumptions and initial conditions, it is possible to describe the processes of heating and cooling of pyroxene rocks under the influence of concentrated solar radiation of high density. It was revealed that the melt cooling rate, which has a strong influence on the dispersion of the obtained material, is determined by the method of melt cooling. To obtain a hardened material with nanosized particles, it is necessary to cool the melt at a rate above 10⁶ deg/s.