INFLUENCE OF GEOMETRIC AND KINEMATIC FACTORS ON COMBUSTION PERFORMANCE.

The influence of geometric and kinematic factors on changing flame configuration is studied for liquid fuel burners. Areas investigated include the effect of fuel spray angle, swirl impeded secondary air flow and incorporating a backward-facing step in the burner tunnel geometry. Wider spray angles produce a more uniform air/fuel distribution with an apparent shortening and widening in flame shape. For increased swirl number, turbulent mixing is enhanced, thereby creating a shorter flame in the combustion chamber. Comparison between a cylindrical and a conical tunnel shows that droplet evaporation is greater when the tunnel geometry contains a sudden expansion, due to the heat transfer issuing upstream from this region, which contains hot recirculating combustion products. The findings indicate that the influence of these variables on the combustion process allows better control of the flame shape and more effective utilization of combustion properties.