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Biofuels as alternative fuels in today’s world are becoming increasingly important for the reduction of greenhouse gases. Here, we present and evaluate the potential of a new alternative fuel based on the conversion of medium-chain fatty acids to biojet (MBJ), which was produced from coconut oil using hydrotreated processes. MBJ is produced by using both deoxygenation and isomerization processes. Several blends of this type of biojet fuel with Jet A-1 were run in a gas-turbine engine (Rover 1S/60, ROTAX LTD., London, England) for the purpose of investigating engine performance and emissions. Performance results showed almost the same results as those of Jet A-1 fuel for these fuels in terms of thermal efficiency, brake-specific fuel consumption, turbine-inlet temperature, and exhaust-gas temperature. The results of exhaust-gas emissions also showed no significant effects on carbon monoxide, unburned hydrocarbon, and nitrogen oxides, while a decrease in smoke opacity was found when blending MBJ with Jet A-1. MBJ performed well in both performance and emissions tests when run in this engine. Thus, MBJ brings hope for the development of aviation biofuels in tropical regions that have an abundance of bioresources, but are limited in technology and investment capital.

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This Annular combustion Chamber is designed for micro turbo jet engine. Combustion chamber is positioned in between compressor and turbine of turbojet. Combustion chamber is designed to increase enthalpy without significant pressure loss. Existing combustion chamber is designed by conventional method of trial and error. To further increase its performance then a optimization is needed. The geometry of the combustion chamber is optimized to maximized efficiency, minimized Pattern Factor, minimized pressure loss and lower temperature on the combustion wall. Varying Parameter is chosen based on Sensitivity Analysis with Spearman Correlation method to choose influential changes on geometry. After sampling process with Latin Hypercube Sampling (LHS) method and followed by interpolation with Kriging method, the combustion chamber then optimized using Multi Objective Genetic-Algorithm (MOGA). Performance of the combustion chamber then evaluated by numerical simulation. The combustion chamber will be chosen if it fulfilled pressure loss and temperature on wall criteria. Final design give better performance with a little increase in efficiency and good Pattern Factor.