Effect of ring and porous plate gas sparger on injection cooling

Short term storage of cryogenic liquid is possible by injection cooling. In this process the liquid is subcooled by injecting a gas through the liquid. Evaporation of liquid into the gas causes subcooling of the liquid, thereby reducing the boil-off loss of the liquid. The rate and extent of subcooling depends on the bubble dynamics and, heat and mass transfer between gas and liquid. Sparger design (type of sparger, number of holes and hole diameter) is an important parameter which dictates the bubble hydrodynamics and hence, the heat and mass transfer between gas and liquid. The effect of sparger type (Porous and ring sparger) on cooling performance of injection cooling has been studied at different gas superficial velocities. A mathematical model based on lumped parameter approach has been developed and simulated for this purpose. Liquid subcooling was achieved for both the types of sparger. However the rate and extent of liquid subcooling was higher for porous plate sparger. Increase in superficial velocity up to a certain value caused the subcooling rate to drop for ring sparger.