The Effect of Gravitational Orientation on Cryogenic Forced Convective Boiling

Abstract

We investigated the heat transfer during tube quenching for developing an on-orbit cryogenic fluid management system. This paper describes the experimental results of tube quenching for two flow directions (upflow and downflow) under terrestrial conditions. Liquid nitrogen is used as the test fluid, and it is injected into a transparent heated tube at a mass velocity of 100-300 kg/m2s. The tubes are made of Pyrex glass, and have two kinds of inner diameter (10mm and 13.6mm). The thermal data reveals that the quenching time during which the inner wall temperature became equal to the liquid nitrogen temperature under upflow conditions is less than that under downflow conditions. The flow visualization data reveals that the droplet size and flow derangement under upflow conditions were greater than those under downflow conditions. This flow behavior leads to an increase in the cooling rate of the tube wall under upflow conditions.