Feasibility Study on Space Reorientation for Liquid Hydrogen Tanks by Means of Evaporated Exhaust Gas

A thermal equilibrium model is established to investigate the heat leak of a space liquid hydrogen tank under different thermal adiabatic structures. The feasibility of the common bulkhead tank in realizing thrust or rotation reorientation by evaporated exhaust gas has been systematically studied. The results indicate that the space radiation heat leak is the primary heat leak in spray-on foam insulation (SOFI) adiabatic tanks. However, the common bulkhead heat leak is dominant in the tank with multilayer insulation (MLI) or self-evaporation vapor cooled shield (VCS). For the continuous stable adiabatic exhaust, the tank with SOFI (over 114 W/m(2)) could realize reorientation with the acceleration of over 5.5 x 10(-4) m/s(2) generated by the exhaust. Meanwhile, the tank that adopted MLI or VCS (below 18 W/m(2)) struggled to achieve gas-liquid separation with the acceleration below 8.7 x 10(-5) m/s(2) generated by exhausting. The rotational angular velocity of the tank through exhausting increases with the fill level dropping and exhaust pressure rising. Reorientation by a TVS intermittent exhaust may be possible in some cases, with sufficient exhaust time. This study provides a theoretical basis for reorientation using the exhaust gas of liquid hydrogen.