At the heart of this COMSOL simulation is that in a high-temperature "vessel" (crucible), silicon carbide powder is heated to turn into a gas and is deposited on the surface of the crystal seed above to grow into a single crystal. Because the temperature distribution, gas flow and composition changes inside are invisible and unmeasurable, numerical simulations are used to predict how gases move and deposit under different temperature, pressure and structural conditions, and how fast the crystals will grow, thereby helping to optimize the preparation process of silicon carbide crystals.