STUDIES ON OPTIMIZATION OF A LIQUID FUEL BASED LOW EMISSION COMBUSTOR

This paper presents experimental and numerical results on a single stage burner configuration with flameless/MILD combustion with liquid fuel. The proposed burner configuration is designed for 20 kW thermal input with heat intensity of 5 MW/m(3) using kerosene as fuel and air at ambient conditions as the oxidizer. Air is injected through four tangential injection holes near the bottom of the combustor results high swirl flow in the combustor helps to enhance the internal recirculation of the combustion products. Computational and experimental analysis is carried out simultaneously for optimization of combustor configuration. In swirl combustor configurations the reactants dilution ration (recirculation) is function of combustor geometry, exit diameter and inlet velocity of air. In the first step of study four different combustor configurations are considered, one cylindrical and three conical combustors with diverging angles of 30 degrees, 45 degrees and 60 degrees. In the second step the effect of exit port diameter on the recirculation and quality of flameless combustion is studied. The exit port diameter varied from 80 mm to 25 mm. In the third step the inlet velocities of air varied by inserting different inlet diameters of 2 to 7 mm in a step of 1mm. Based on combustion completeness and emission analysis, the 60 degrees diverging angle combustor with air inlet diameter of 4 or 5 mm and 25 mm exit diameter is considered as optimistic configuration to obtain flameless combustion mode with liquid fuels. The acoustic emissions and the emissions of CO and NOx are measured for different configurations.