Feasibility analysis and application consideration of a rapid method to obtain subcooled cryogenic propellants

Subcooled cryogenic propellants that can significantly improve its own thermodynamic performances have attracted more and more attentions. To shorten subcooled time, a rapid method to obtain subcooled degree is proposed. To illustrate the thermodynamic essence of the method proposed as a whole process system, the thermodynamic analysis is carried out to explain the throttle cooling process. To quantitatively compare and explain the rapid feature, the thermodynamic model of cooling rate is developed to calculate the subcooled time and liquid consumption, and nonlinear equations are solved numerically. The effects of several key parameters are then analyzed. The results show that the method presented in this paper is feasible and effective. Compared with the conventional pumping decompression method, the subcooled time used the rapid method can drastically shorten, and even cut down on more than one half in some cases. The cooling way is changed from a conventional type of passive cooling to the novel type which combines active cooling with passive cooling. Subcooled time and liquid consumption are inversely proportional to the pumping speed, linearly positively correlated to the inlet pressure of the throttle valve, and exponentially positively correlated to the inlet temperature of the throttle valve. The proposed method can be applied at the launch site of large cryogenic launch vehicles in the future.