Multi-component effect and reaction mechanism for low-temperature ignition of kerosene with composite enhancer

Abstract

A composite additive design method was proposed in our previous study to improve the low-temperature ignition performance of a surrogate fuel, n-decane. For multi-component liquid hydrocarbons, the mechanism for low-temperature ignition enhancement should involve the combination of small-molecular hydrocarbons in the base fuel and the composite enhancer, i.e., the multi-component effect. In this study, the influence of the multi-component effect on low-temperature ignition performance of kerosene-based hybrid fuel (kerosene with the addition of various concentrations of 1:1 methoxydiethylborane/tetrahydrofuran solution) was experimentally investigated and the reaction mechanism was explored. To evaluate the vaporization and ignition characteristics, thermogravimetry analysis and droplet hot surface ignition experiments were systemically conducted. The results indicate that the ignition temperature of the kerosene-based hybrid fuel is reduced to 128 °C, which is over 500 °C lower than that of neat kerosene. With the same enhancer proportion, the ignition performance of the kerosene-based hybrid fuel is superior to that of n-decane-based hybrid fuel. The droplet-hot plate experiments of hybrid fuel with the addition of n-pentane show that the small-molecular hydrocarbon plays a significant role in the reduction of ignition temperature and ignition delay time. The multi-component effect has advantages of achieving a better low-temperature ignition performance. The effects of the composite enhancer on hydrocarbon reaction pathway were analyzed to give a further explanation of the ignition enhancement mechanism. Free radicals produced by methoxydiethylborane self-oxidation promote the reaction of hydrocarbons at low temperatures. The exploration of the mechanism for low-temperature ignition of kerosene with composite enhancer could shed light on the jet propellant design.