PREDICTIONS OF RADIATIVE-TRANSFER FROM A TURBULENT REACTING JET IN A CROSS-WIND

Predictions of the structure and received thermal radiation around a turbulent reacting jet discharging into a cross-flow have been made using a finite-difference scheme for solving the fluid dynamic equations. The model employs a two-equation, k-epsilon turbulence model. The gas-phase, non-premixed combustion process is modeled via the conserved scalar/prescribed probability density function approach using the laminar flamelet concept, whilst soot formation and consumption is included through balance equations for mass fraction and particle number density which admit finite-rate kinetic effects. Both flamelet and sooting prescriptions are derived from a global reaction scheme for hydrocarbon combustion. Levels of radiation received around a flame are obtained using the discrete transfer method coupled to a narrow band model of radiative transfer. In order to assess the usefulness of the model for predicting the consequences associated with atmospheric venting and flaring operations, solutions are compared with experimental data from laboratory and field scale studies of natural gas flames. Predictions are shown to be in good agreement with measurements of received radiation made around all the flames examined. In particular, results for a number of sooting strain rates indicate that a single rate suffices for predicting the radiation received about a wide range of flame sizes.