Measuring Of Heat Sink Of Endothermic Hydrocarbon Fuels And Some Factors

It is very important progress that developing hypersonic flight in aerial history. Excellent fuel is the key factor in realizing hypersonic flight. Advanced fuels are the key technology among flight system, too. Today, it is necessary that fuels have not only high energy density, but also excellent heat-absorbed capacities. The traditional fuel can't meet the demands at hypersonic flight just using their physical heat-absorbed capacities. Therefore, developing chemical heat sink is a significant content on fuel study.The present work is to measure the heat sink of fuel at various conditions using our homemade high temperature heat conduction type calorimetric system according to Tian equation Ωi＝KΔi+ΛdΔi/dt. The instrument constant K was measured by electric heating; and to validate veracity of K through measuring the heat sink of nitrogen. The results show that the design of heat sink measuring instrument is reasonable and the data is accurate. We mainly study the effects of some factors on fuels heat sink:1. Studying on the effect of temperature on heat sink of n-hexaneHeat sink of hexane is increased at higher temperature. The total heat sink and chemical heat sink of n-hexane is increased by 453J/g and 388J/g respectively between 450~500℃; the total heat sink and chemical heat sink of n-hexane is increased by 325J/g and 294J/g respectively between 500~550℃.2. Studying on the effect of pressure on heat sink of n-hexane We mainly study supercritical pressure's effects on heat sink of n-hexane. Experiment result show that the change of heat sink is very remarkable at two sides of critical point. Heat sink of n-hexane is increased by 164J/g at 450℃, 121J/g at 500℃ at two sides of critical point. 3. Studying on the effects of initiators on heat sink of n-hexane We selected seven initiators and put them into n-hexane , the concentration of initiators are 0.5wt%,1.0wt% and 2.0wt% respectively. The experiment results suggest that tert-butyl peroxide is best initiator if we only consider it's the effect of initiation. The heat sink of n-hexane is increased by 400~500J/g when tert-butyl is put into at 450℃. 4. Studying the effects of compound initiators on heat sink of n-hexaneBecause of various initiators bring various effects. So that, we put compound initiators into n-hexane in order to study effects of these mixture on heat sink. The results show that compound initiators bring us the effects we desire.5.Measuring else fuels' heat sinkIn experiment, we selected n-octane, iso-octane, n-decane and cyclo-hexane. The results showed the effects of initiators on alkyl was more remarkable than on iso-alkyl and cyclo-alkyl. And various brought various effects on major gas products. The deposit during cracking was studied in term of deposit mechanism. Its appearance was analyzed in according to the detail that SEM photo provide. We discovered there are two shapes in deposit, carbon whisker and carbon particle.