Theory for Heat Transfer with Phase Change
Heat Transfer with Phase Change
Heat transfer and phase change are inter-related processes:
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Matter exists in a certain phase, liquid, solid or gas, at equilibrium under a given condition of pressure and temperature. The phase transition occurs when the temperature and pressure of the system come across a critical condition at which the material changes phase. The critical value of temperature at which the transition occurs for a given reference pressure can be computed through statistical physics or tabulated from experiments. In the following, we assume that the phase change is driven by the temperature, neglecting all other factors that may affect phase change, as equilibrium time, or purity of the material.
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At the macroscopic and mesoscopic level, phase change costs or releases a certain amount of energy which is called latent heat of phase transition, which is an input of the model. Because there is a balance between sensible and latent heat, phase change induces temperature variations.
The dedicated features for phase change simulation that are available in the Heat Transfer module handle models were it is assumed that the different phases are non miscible so that each phase is located in a distinct domain. The simulation predicts the position of the phase change interface and the associated thermal effects. The following sections present the two numerical methods available to do the modeling:
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Stefan Condition
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Apparent Heat Capacity Method