Combustion characteristics of butanol, butyl butyrate, and Jet A-1 in a swirl-stabilized combustor

Significant growth in the aviation industry has also raised concern on the impact of this sector in terms of environmental pollution. Bio-derived fuels are going to play an important role as potential alternative aviation fuels in the near future to mitigate the carbon footprint. Ethanol is a candidate biofuel which is widely used in many countries in the petrol-ethanol blend for S.I. engines. However, the interest in utilizing biofuels in aviation gas turbine engines is relatively recent. In comparison to ethanol, n-butanol possesses some better fuel properties such as higher energy density, less hygroscopic, lower vapor pressure, higher flash point. Butyl butyrate is another potential candidate which can fulfill the chemical property requirements of alternative aviation fuels. However, compatible substitutes for currently used aviation fuel (such as Jet A-1) are still at the early stage of development. The present study deals with experimental investigations of combustion characteristics of aviation kerosene (Jet A-1), butanol, butyl butyrate, and blends of the last two fuels with Jet A-1 in a swirl-stabilized gas turbine type combustor. Visualization of flame, measurement of temperature inside the flame, and exhaust emissions at the combustor exit are carried out to compare the performance of various fuels relative to Jet A-1. Spray penetration length, ligament length, droplet diameter, and spray cone angle of various fuels obtained using high-speed imaging technique are analyzed to understand the combustion characteristics. Fuel properties of individual fuels and blends are also measured and compared to probe the variation in spray and combustion performances.