Performance of a Trapped Vortex Spray Combustor

Abstract

The performance of a liquid-fueled trapped vortex (TV) combustor is analyzed both experimentally and computationally. The TV cavity, formed between a forebody and an afterbody, is placed coaxially inside a combustor shell. Fuel and primary air are injected from the inside face of the afterbody. The flame holding capability of this trapped vortex configuration is evaluated for different primary equivalence ratios. Very low overall lean-blow-out (LBO) equivalence ratios are obtained for the TV combustor over a wide range of annular and primary airflow rates. It is found that by injecting the primary air with a tangential velocity component the circumferential mixing is improved without disrupting the vortex trapped in the cavity. The performance of the TV combustor is also evaluated through emissions measurements at the exit of the combustor and temperature distribution inside the cavity. Numerical simulations are performed for the TV configuration with a k-ε turbulence model coupled with a PDF combustion chemistry model for simulating liquid spray combustion. The predicted results are in reasonable agreement with the measurements and provide an assessment of the flow distribution in the cavity region.