Impact of a Jet A-1/HEFA blend on the performance and emission characteristics of a miniature turbojet engine

It is forecast that in the future, alternative fuels derived from non-petroleum sources will become the basic propellant for turbine aircraft engines. Currently, five types of aviation turbine fuel containing synthesized hydrocarbons are certified and accepted, and allow adding a maximum of 50% of synthetic component to conventional fuel. The experimental performance and the emission characteristics of a turbojet engine were investigated in this paper. The studies were conducted with the use of a miniature turbojet engine, which is the main component of a laboratory test rig. The test rig is an interesting solution for engine research, due to the fact that studies concerning full-scale aircraft engines are very complex and expensive. The literature of the subject contains many papers using small-scale turbojet engines for testing alternative fuels. However, most of them concern components of fuels, e.g. biodiesel, butanol, which do not have direct application in aviation. Two different fuel samples, a conventional Jet A-1 fuel and a blend of 48% synthesized paraffinic kerosene from hydroprocessed esters and fatty acids process with Jet A-1 were tested. This process is one of the routes of producing alternative fuel for aviation, approved by ASTM standard. The test rig studies were performed according to a specific profile of engine test, which models different modes of a turbojet engine's operation. The obtained results are compared in relation to the results for neat Jet A-1 fuel and then discussed.