Three-Dimensional Analysis of Liquid Hydrogen Cryogenic Storage Tank

*† This paper presents a study of fluid flow and heat transfer in a cryogenic storage tank for liquid hydrogen using a three-dimensional model for numerical simulation. The model includes a tank with cylindrical wall and oblate spheroidal top and bottom, a heat pipe located along the axis of the tank, and a pump-nozzle unit that collects fluid at the suction inlet and discharges at its nozzle face onto the cool tip (evaporator) of the heat pipe in order to prevent the fluid to boil off. A steady state condition was assumed. Simulations with different normal speeds of fluid discharged at the nozzle face were run for a parametric analysis. Typical distributions of velocity and temperature are presented. Average speed and maximum temperature for each case are evaluated for assessing mixing and boiling effects, respectively. Simulations using an axi-symmetric model, which represents the case of an array of many pump-nozzle units installed around the heat pipe, were also carried out with the same fluid discharge speeds as those of the three-dimensional cases for comparison. For both models, the results show that as the normal fluid speed at the nozzle increases, the average fluid speed increases whereas the maximum temperature decreases. It is also found that with the same fluid speed discharged normally from the nozzle face the axi-symmetric model gives higher average speed and higher maximum temperature compared to the threedimensional model.