Investigation of Flow Features in a Vertical Cryogenic Feedline During Non-Flow Conditions

In the present work, experiments and computational fluid dynamics (CFD) simulations are performed to investigate the flow behaviour in a cryogenic feedline under stagnant conditions using liquid nitrogen as the test fluid. The effect of heat-in-leak into liquid nitrogen, and feedline aspect ratio on the flow pattern are brought out. The various aspect ratios are achieved by varying the pipe diameter from 17 mm to 100 mm for a constant length of 2 m. In the experimental study, the pressure and temperature of the fluid is measured and the flow pattern in the feedline is visualized. It is found that for the conditions studied, the flow in a bottom-closed feedline ends up in the boiling regime and geysering does not occur. Further, studies show that for larger feedline diameter, the boiling is suppressed due to the free-convective currents formed in the feedline.