Pollution reduction from flares by swirl vanes in a cross-flow

The effect of swirl on the performance of a flare stack was experimentally investigated as a passive control technique for combustion in a cross-flow. The burner comprised a circular fuel nozzle with a co-annular airflow, swirled by a concentric vane swirler, with a crosswind of air at the flare tip. It was found that the flames issuing from swirl-vane flare tip were shorter and had wider flame stability limits than the flames issuing from a circular flare tip. Recirculation zones in the wake region of the flare stack were found to persist at relatively higher momentum ratios between the fuel jet and the crosswind. This enhancement was accompanied by an increase in the mixing/combustion efficiency.

Keywords: combustion, cross-flow, flame stability, gas flaring, non-premixed flames, swirl vanes, pollution reduction, environmental pollution, flare stacks