Study On Stability And Endothermic Capability Of Hydrocarbon Fuels

As fuels used in aircrafts, they should had high stability and heat sink. The majorfactor influencing the stability of fuels is the formation of solid deposits throughthermal oxidization or thermal cracking. With the development of higher Mach engine,the physical heat sink of fuels cannot meet the demands of high super-Mach fight,which need the chemical heat sink to satisfy the requirements for the cooling ability offuels. In this paper, high-pressure differential scanning calorimeter (PDSC) is used tostudy the stability and chemical heat sink of hydrocarbons, with the effect of additivesconsidered.After calibration, PDSC is used to study the anti-oxidation ability ofhydrocarbons. The results show that the ability of anti-oxidation decrease as the order:cyclohexane>normal alkanes >JP-10>decalin>MCH >butyl benzene>tetralin. As fornormal alkanes, the ability of anti-oxidation decrease with carbon chain increases.The results of research on hydrocarbon thermal cracking show that thermalcracking temperatures decrease as the order: tetralin> cyclohexane> JP-10≈normalalkanes≈decalin>butyl benzene. Methylcyclohexane has the largest chemical heatsink, while butyl benzene has smallest chemical heat sink.The use of anti-oxidation additives such as BHT and TPP, can improve thethermal oxidation stability of hydrocarbon fuels by increasing oxidative temperatureand decreasing oxidative deposits.In order to study the effects of initiators on cracking temperature and crackingendotherm, six initiators of three types are chosen to be used in n-Octane. Theinvolvements of initiators decrease the cracking temperature, while increase the heatsink that leads to fewer deposits and better thermal stability and cooling ability. In allsix initiators,Cumyl-peroxide(CP) has the best performance. With 2% concentrationof CP, the cracking temperature decrease by 68°C and chemical heat sink increase by385J/g.Products distribution of thermal cracking is studied, the results of which showthat products distribution varies at different cracking temperature.