Thermal Mathematical Model of a Two-Phase Circuit with Mechanical Pump and Thermal Hydraulic Accumulator

The increase in heat release in spacecraft, along with their increasing size, has posed the challenge of developing thermal regulation systems that utilize a two-phase boiling coolant. In this system, heat is accumulated in the form of latent heat of vaporization, which allows for the transfer of significantly larger amounts of heat per unit mass flow rate of the coolant compared to the use of a single-phase coolant. Furthermore, the use of heat exchange during boiling enables the temperature of objects to be maintained close to the boiling temperature of the chosen coolant throughout almost the entire circuit. All heat-transfer processes that occur during changes in the state of matter take place significantly more intensively than in conventional convective heat exchange; therefore, the mass of the heat-exchange equipment, valves, and control elements in a two-phase circuit will be considerably less than their mass in a circuit with a single-phase coolant. The circulation of the coolant in two-phase thermal management systems should be carried out by capillary or mechanical pumps. For high-power applications, it is more advantageous to use a two-phase boiling coolant with a mechanical pump. The development of thermal regulation systems based on a two-phase circuit should be preceded by the creation of a mathematically adequate model of the two-phase boiling coolant. A mathematical model has been proposed that allows for the analysis of the operation of the two-phase boiling coolant and the calculation of the hydrodynamic and heat- and mass-transfer processes.