Non-linear vapour—liquid phase separation including microgravity effects

Abstract

Vapour—liquid phase separation, by means of porous plugs, for He II vessels has been investigated with emphasis on the non-linear transport regime. The data are indicative of a normal fluid flow ‘bottleneck’ which controls in the pore size range of the order of 1 μm. The results are described by a phenomenological equation for large pores, suitably modified to take care of the pore-size dependent entropy transport. The latter is coupled, via a two-fluid model and first law constraints, to the mass throughput of the plug. Zero gravity constraints suggest that this mode is dominant once the terrestrial gravity force has been removed.