Experimental and computational fluid dynamic study of reacting gas jet in liquid: flow pattern and heat transfer

Abstract

The flow behavior of a jet reactor (consisting of a gaseous jet submerged in a molten-metal bath) is very complex. These are operated at high temperatures (1500-3000 K) and need to be contained within a heavy metal enclosure. The design of such reactors requires a prior knowledge of the jet dimensions, flow pattern and heat transfer characteristics. However, the fuel opaqueness and the high temperature of the jet create difficulties in observing the reaction mass visually and therefore the literature contains a very brief account of the experimental measurements of the flow pattern. Hence, a systematic study has been undertaken with a reaction pair (HCl gas jet submerged in aqueous NH₃), which has the potential for simulating the real systems. The present work is concerned with the CFD simulations by employing k-ε turbulence model and large eddy simulations (LES). The measurements and simulations have been carried out over a wide range of gas velocities (53-323 m/s) and these have been compared with the CFD simulations. A comprehensive comparison has also been made between the k-ε and the LES for the mean flow, temperature and the turbulent kinetic energy. An attempt has been made to understand the relative performance of these models. Further, complete energy balance has been established between the energy supply rate through the jet and the energy dissipation rate within the reactor. The plume characteristics obtained from CFD simulations have been compared qualitatively with the photographic images.