Steam Jet Condensation in a Pool: From Fundamental Understanding to Engineering Scale Analysis

The phenomena of direct contact condensation (DCC) of steam jet submerged into a water pool occurs due to the actuation of steam discharging devices in many industrial processes and there are practically two kinds of technical concerns to consider. The one is a concern on the thermal mixing in water pool. The other concern is on thermo-hydraulically induced mechanical loads on the structures of relevant systems. Both concerns may be inter-related with each other in terms of thermally-induced hydrodynamic loads on the relevant system. There are two kinds of viewpoints in terms of DCC-induced thermal mixing in a pool: the local hot spot, which may affect the stability of condensation phenomena, and the thermal stratification, which usually exists over the whole pool region. Both aspects can be well described only if the local behaviour of condensing steam jet and the resultant turbulent jet in a pool are well understood. In this paper, the DCC-related thermo-fluid dynamic features are discussed, based mainly on our experiences of developing the relevant engineering systems over the past years. Fundamental characteristics of condensing steam jets are discussed, including the local behaviour of condensing jets and the resultant turbulent jet to importantly affect the macroscopic circulation in a pool. Then the local analysis of condensing jet behaviour and the global analysis of thermal mixing in a pool are discussed with practical application to engineering in mind.