Thermal mathematical model of a two-phase circuit with mechanical pump and thermal hydraulic accumulator

Abstract

Growing heat release in spacecraft accompanied by simultaneous increase in its amount set the task of developing thermal control systems using the two-phase boiling coolant. It accumulates heat in the form of latent vaporization heat making it possible to transfer much larger amount of heat per the coolant unit mass flow rate than at using a single-phase coolant. In addition, introduction of heat transfer at boiling allows maintaining the object temperature in almost the entire circuit close to the boiling temperature of the selected coolant. All heat transfer processes that occur, when the substance aggregation state changes, are much more intensive than with the conventional convective heat transfer; therefore, the mass of heat exchangers, fittings and control elements of the two-phase circuit would be significantly lower than their mass in a single-phase coolant circuit. Capillary or mechanical pumps should pump the coolant in two-phase systems to ensure the thermal regime. At high power, it is more advantageous to use the two-phase boiling coolant with a mechanical pump. Creation of thermal control systems based on the two-phase circuit should be preceded by elaboration of an adequate mathematical model of the two-phase boiling coolant. Mathematical model is proposed that could be used to analyze operation of the two-phase boiling coolant and calculate hydrodynamic, heat and mass transfer processes.