Numerical studies on unstable oscillatory direct contact condensation (DCC) of oxygen vapor jets in subcooled flowing liquid oxygen

Abstract

At the booster turbopump exit of a high pressure staged combustion cycle based cryogenic rocket engine, hot gaseous oxygen after driving the booster turbine mixes with subcooled liquid oxygen from the booster pump leading to a complex phenomena of direct contact condensation of hot oxygen gas. The aim of the present investigation is to numerically study the condensation of oxygen vapor jets in subcooled liquid oxygen using a two-fluid two-phase model in the Eulerian framework to understand the mixing process at the booster turbopump exit. The unstable nature of the oxygen plume shapes at cryogenic temperatures have been examined and the stable to unstable transition in an unstable direct contact condensation cycle have been analyzed. A detailed parametric study has been conducted using the Box-Behnken design and suitable correlations are developed for the critical design parameters viz., overall averaged heat transfer coefficient and dimensionless maximum vapor penetration length. Finally, the maximum pressure oscillation amplitudes associated with unstable oscillatory oxygen direct contact condensation are characterized. The results of the present investigation will be helpful in designing experimental set-up for studying the unstable direct contact condensation at cryogenic temperatures and will serve as preliminary guidelines for the design of an oxygen direct contact condenser, which hitherto is unavailable in the open literature.