Ignition delay study of next generation alternative jet fuels in a rapid compression machine

Abstract

Alternative fuels have been widely and actively investigated recently to alleviate an impending energy crisis. Rising environmental, economical, and political concerns requires employments of alternative sources of energy other than conventional fossil fuels. Alternative aviation fuels from diverse bio-feedstock have been introduced to reduce dependency on fossil fuels and environmental effects. However, combustion characteristics and properties of the newly developed fuels are not yet comprehensively understood. Recent studies have been examined to obtain combustion characteristics of alternative aviation fuels, as well as physical and chemical properties. The primary goal of this study is to determine the ignition delay time of jet fuels of interest; conventional, alternative, and surrogate blends. By measuring the pressure trace of autoignition in rapid compression machine, ignition delay time is captured through the pressure derivative. Category A fuels represent conventional jet fuels. Three of the category A fuels of interest are Jet A(Jet A-2), the nominal commercial aviation fuel, JP-8(Jet A-1) and JP-5(Jet A-3), both of which are conventional military jet fuels. Fuels in category C are the surrogate fuels with specific targeted physical properties, or chemical composition. They are either produced from bio feedstock, or blend of them with conventional fuels or surrogate components. Amyris Farnesame, Gevo ATJ(C-1), blend of tetradecane and trimethylbenzene (C-2), blend of JP-5 and farnesane (C-3), blend of Sasol IPK and Gevo ATJ (C-4), blend of decane and trimethylbenzene (C-5) are tested through the study. A rapid compression machine at the University of Illinois at Urbana-Champaign is used for testing, with the direct test chamber charge preparation method. DTC configuration has advantages in avoiding thermal decomposition and controllability