Semi-empirical Combustion Efficiency Prediction of an Experimental Air-Blasted Tubular Combustor

The preliminary gas turbine combustor design process uses a huge amount of empirical correlations to achieve more optimized designs. Combustion efficiency, in relation to the basic dimensions of the combustor, is one of the most critical performance parameters. In this study, semi-empirical correlations for combustion efficiencies are examined and correlation coefficients have been revised using an experimental air-blasted tubular combustor that uses JP8 kerosene aviation fuel. Besides, droplet diameter and effective evaporation constant parameters have been investigated for different operating conditions. In the study, it is observed that increased air velocity significantly improves the atomization process and decreases droplet diameters, while increasing the mass flow rate has a positive effect on the atomization—the relative air velocity in the air-blast atomizer increases and the fuel droplets become finer. Furthermore, experimental results gave a maximum deviation of 1.5% in the combustion efficiency using the revised correlations. Finally, in conclusion, the reaction rates are the main contributor to the inefficiency of the tubular combustor due to the high aerodynamic loads related to the combustor dimension and operating conditions.