Propulsive and combustion behavior of hydrocarbon fuels containing boron nanoparticles in a liquid rocket combustor

Abstract

Nano-sized energetic particle as fuel additives is of great significance for liquid hydrocarbon fuels that will exhibit high-density and high-calorific value in high-speed propulsion systems. An experimental investigation has been conducted to determine the propulsive and combustion behavior of hydrocarbon fuels containing boron nanoparticles. In this study, nano-sized boron particles with average diameter of 20 nm are added into the basic fuel JP-10 and quadricyclane, respectively. They are then referred as slurry fuels and burned in the rocket combustor using pure oxygen as the oxidizer. With a wide range of excess oxidizer coefficients, three parameters characterizing the propulsion performance are employed to evaluate the effect of boron nanoparticles on hydrocarbon fuels. It is found that the boron-based slurry fuel showed superior density specific impulse. It is increased by 1.18% and 1.44% when the addition of boron particles with 10% mass fraction are added into the basic fuel JP-10 and quadricyclane, respectively. Combustion depositions of the boron-based slurry fuel located at different positions are then collected for deep analysis by means of the energy dispersive spectrometer, X-ray diffractometer, and scanning electron microscope. Comprehensive microanalysis results demonstrate that boron particles first combine with the C-element in the hydrocarbon fuel to form the boron carbide with a reticular structure, and then the boron carbide oxidizes to form block-shaped boron oxide. However, the surface boron oxide hindered the further reaction of the internal boron carbide, which limits the energy release of the boron particles and ultimately leads to the unsatisfactory combustion efficiency of the slurry fuel.