Computational Study of Biofuels Effect on Pressure and Temperature Changes Across Two-spool High Bypass Turbofan Engine Components at Various Engine Rotational Speeds

Abstract

This study evaluates the effect of biofuels on pressure and temperature changes across the CFM56-3 gas turbine engine components and the overall engine performance. The analysis was performed numerically using the Gas Turbine Simulation Programme (GSP11) at increasing high-pressure turbine (HPT) shaft speeds ranging from 8400 rpm to 10 400 rpm. The biofuels used in this work were Jatropha Bio-Synthetic Paraffinic Kerosene (JSPK) and Camelina Bio-synthetic Paraffinic Kerosene (CSPK). The fuels were tested as pure and as a blend with Jet-A. Results revealed linear increases in the temperature and pressure across the compressor outlet, combustor outlet, and turbine outlet as HPT speed increases. Temperature and pressure obtained from biofuels are lower than that of the Jet-A fuel. However, the pressure reduction becomes insignificant at increasing shaft speed and surpassed Jet-A at 10 400 rpm. Utilising biofuels causes temperature reduction across the entire gas turbine components. The reduction is beneficial particularly at the turbine blade, as the blade's primary failure is mainly associated with thermal related fatigue failure. At a lower shaft speed, the thrust produced from biofuels is lower due to the temperature reduction. However, the reduction became negligible as the shaft speed increases and exceeded Jet-A at 10 400 rpm due to pressure increment. At all speeds, fuel flow and thrust specific fuel consumption (TSFC) of biofuels is 1% to 3% lower than Jet-A. Therefore, it indicates that utilising biofuels improved the engine thrust while consuming less amount of fuel.