An Experimental Study Concerning the Pressurization and Stratification of Liquid Hydrogen

Abstract

The so-called temperature stratification phenomenon, which has been observed in containers of cryogenic fluids under certain conditions, is of sufficient interest in the field of cryogenic engineering to warrant special investigation. Areas in which the results of such research may be applied profitably include those concerning the transfer of liquefied gases by pres sur ization, the transfer of liquefied gases by pumping, and the sealed storage of liquefied gases. In the first case, the stratification of contents in a vessel used to supply transfer fluid permits the utilization of subcooled liquid, whose properties are desirable from the aspect of single-phase flow characteristics. In the second case, stratification provides a means to attain, and sustain, net positive suction head for transfer by pumping, the absolute magnitude of NPSH required here depending upon both fluid and pump characteristics. For the final case, the effect of stratification is undesirable, generally, due to the accompanying promotion of an excessive rate of pressure rise in the storage vessel ullage space; the unde sir ability is pronounced for sealed “no-ioss” transport containers in which the maximum time permissible in transit is a direct function of the container design pressure.

This work was supported by the U. S. Atomic Energy Commission.