Abstract:

The fluid temperature distribution is experimentally studied with the working fluid R123, based on the ground thermodynamic vent system experimental rig. The present experiment is conducted under the initial liquid height of 0.595 m and the heat load of 800 W during the tank pressurization, mixing injection depressurization, throttling refrigeration and free cooling phases. Experimental results show that the fluid temperature stratification is greatly developed during the pressurization phase. During the mixing depressurization process, the increase rate of the thermal layer development is 1.54 mm/min with the circulation volume flow of 96 L/h. While the circulation volume flow increases to 152 L/h, it is about 1.07 mm/min for the thermal layer development. For the present experiment, it consumes 5.48 h for the whole development of the thermal stratification. The liquid temperature is limited within 1.98 ℃, while the vapor has the maximum temperature reduction of 13 ℃, during the throttling refrigeration phase. In the free cooling part, the effect of the injection cold fluid disappears 15 min later. Under the cooling of the external air, a linear vapor temperature distribution finally has a tendency of the minimum value in the top and the maximum value in the interface. While for the liquid temperature, it reduces parallel to the direction of the temperature decrease with the constant rate.

Key words: Cryogenic propellant, Thermal stratification, Thermodynamic vent, Pressure control mode