Prediction of Pressurant Mass Requirements for Axisymmetric Liquid Hydrogen Tanks

Experimental data from several test series are compared to an existing correlation that predicts the amount of pressurant gas mass required to expel liquid hydrogen from axisymmetric tanks. It was necessary to use an alternative dee nition of the tank equivalent diameter to accommodate thermal mass in the tank wall that is initially warm, and to accommodate liquid residuals in the tank after expulsion is stopped. With this modie cation, the existing correlation predicted mass requirements to within 14% of experimental results. Revision of the correlation constants using a nonlinear least-squares e t of the current experimental data has a minor effect, thus supporting the validity of the original correlation’ s form, its e tted constants, and the alternative dee nition of the tank equivalent diameter.