Effects of aluminum powder additives on deflagration and detonation performance of JP-10/DEE mixed fuel under weak and strong ignition conditions

As a high-density hydrocarbon fuel with good comprehensive properties, JP-10 is widely used in scramjets and detonation engines. Previous work has improved the ignition susceptibility and reduced incomplete combustion product concentration of JP-10 liquid fuel by blending diethyl ether (DEE). However, the density and bulk calorific value of hydrocarbons do not increase indefinitely with the increase of the ring structure, and the low temperature properties of the fuel gradually deteriorate with the increase of density. Therefore, adding metal dust with higher combustion calorific value to improve the energy density of mixed fuel is a new solution. In the present work, the deflagration and detonation properties of multiphase mixed fuels obtained by adding three aluminum powders with different morphologies and particle sizes (flake aluminum powder, small spherical aluminum powder, large spherical aluminum powder) to the JP-10/DEE mixed fuel were investigated. Under weak ignition conditions, the addition of aluminum powder increases the average burning rate of the multiphase mixed fuel and flame intensity significantly. The increase rate of the flame intensity when spherical powders are added is lower than that of the flake aluminum powder. The addition of aluminum powder is conducive to the early acceleration of deflagration, and the flame intensity reaches a high level earlier. Although the aluminum powder increases the energy of the reaction system, it also aggravates the incomplete combustion of JP-10/DEE in the oxygen-depleted state, and generates a large amount of soot. Under the strong ignition conditions, the DDT process of JP-10/DEE/aluminum powder can be divided into four stages: the slow propagation stage, shock wave formation stage as a result of compression wave superposition, coupling evolution stage of shock wave and flame front, and the detonation stage, respectively corresponding to four different pressure wave pattern. The strong ignition method greatly accelerates the evaporation of JP-10/DEE and the melting of the aluminum core in the initial stage, so that the multiphase mixture quickly changes from a slow propagation mode to a strong defla-gration mode.

Automated summary

In this study, the deflagration and detonation properties of multiphase mixed fuels obtained by adding different morphologies and particle sizes of aluminum powder to the JP-10/DEE mixed fuel were investigated. Under weak ignition conditions, adding aluminum powder significantly increases the average burning rate and flame intensity of the multiphase mixed fuel. However, the addition of aluminum powder also leads to incomplete combustion and the generation of a large amount of soot in the oxygen-depleted state. Under strong ignition conditions, the DDT process of JP-10/DEE/aluminum powder can be divided into four stages, corresponding to four different pressure wave patterns.