| Thermal cracking of hydrocarbon is an effective way to remove waste heat of aircrafts.To achieve effective cooling ability and provide enough propulsion energy,hydrocarbon fuels have to have high heat sink as well as high energy density.This paper compounds n-decane with decalin and JP-10 to produce hydrocarbon fuel with moderate density and heat sink.The objective of this paper is to study the influence of structure and composition of hydrocarbon fuels on the behavior of supercritical pyrolysis and construct quantitative relationships between structure and properties.The parameters of n-C10,decalin,JP-10,n-C10/decalin mixtures and n-C10/JP-10 mixtures thermal decomposition including conversion,products distribution,heat sink are studied under supercritical p hase(4 MPa,823 K-953 K).It is found that n-C10 has accelerating effect on the decomposition of JP-10 and decalin.The accelerating effect decreases with increasing temperature.The densities of mixtures are higher than that of pure n-C10.Mixing up n-C10 with cyclic compounds can improve the chemical heat sink of cycloalkanes.Coking of pure n-C10,JP-10,decalin and six binary mixtures in the electrically heated tubular reactor(EHTR)has been investigated.It is found that under same coking conditions(4 MPa,933.15 K,o.8 g/s),n-C10 has the highest amount of coke.Compared with the yield of coke formed from n-C10,the presence of decalin and JP-10 decrease the formation of coke.At the entrance of tubular,the amorphous carbon is dispersed on the surface of reactor.At the bottom of tubular,amorphous carbon and filamentous carbon may appear.At the end of tubular,there is compact amorphous carbon.Different reactants coking,the morphologies are different even at the same position of the tube.Structural index is used to distinguish hydrocarbons with different structure and composition.Physical and chemical properties are connected with structural indexes.The results show that there are good quantitative relationships between structural index and physical properties(density and C_p).These quantitative relationships may provide fundamental information for developing hydrocarbon fuels. |
