Structure of Turbulent Reacting Gas Jets Submerged in Liquid Metals

Abstract

A model for predicting the turbulent, multiphase, diffusion-flame structure of a gaseous oxidizer jet submerged in a molten-metal fuel is described. Axisymmetric flow was considered using the locally homogeneous flow approximation of multiphase flow in conjunction with a well-calibrated k-e-g model of turbulence properties. Effects of buoyancy were considered in the governing equations for mean properties. The model was evaluated using existing data for vertical chlorine jets submerged in dilute-Na/NaCl molten baths at atmospheric pressure. Combustion products for these reactants are condensible; therefore, the portion of the flow containing gas has a finite penetration length—somewhat analogous to flame lengths in gaseous single-phase diffusion flames. Predicted and measured penetration lengths and mean temperatures along the jet axis were in fair agreement using conventional turbulence model constants established for single-phase flows. The predictions indicate a complex flow structure containing several solid and liquid phases due to the large temperature range of the process and the miscibility properties of the reaction products Computations for injection of chlorine into pure sodium showed that while reaction is completed near the injector, the gas phase persists for a considerable penetration length since vapors formed in high temperature portions of the flow must recondense.