Method of Thermal Design of Branched Two-Phase Circuits of Thermal Management Systems

In this paper, we propose the construction of a thermal physico-mathematical model of a contour heat pipe with a mechanical pump, based on the results of experimental validation of which a model of a heat pipe with a branched contour is constructed. This model consists of 55 isothermal units and hydraulic resistances varying along the length of the pipe. The models have low sensitivity to errors in setting the heat-transfer coefficients and hydroresistance. With the help of this model, data are calculated by the Runge–Kutta method of the fourth order of accuracy. The correspondence of the experimental and calculated parameters is good. According to this method, calculations of the functioning of a two-phase experimental circuit which has been subject to thorough extensive ground and flight testing are carried out. Propylene is used as a coolant. The temperature difference between the calculated and experimental data is about 1.5°C (at a saturation temperature of 25.5°C); the difference in the pressure drops is about 0.05 atm (with a pressure drop at the pump of 0.7 atm and an absolute pressure in the circuit of 12.2 atm.).