Effect of Fluorides Coated Nano-Aluminum Powder on Combustion Properties of HTPB Based Fuels

To study the effect of fluorides coated nano-aluminum powder on combustion properties of hydroxyl-terminated polybutadiene (HTPB) based fuels, two kinds of HTPB based fuels with fluorides coated nano-aluminum powder and without additives were prepared by a vacuum casting method and their combustion properties in gaseous oxygen flow were measured. The theoretical specific impulse and adiabatic flame temperature of fuels were calculated using NASA-CEA program. The results show that the regression rates of two kinds of fuels increase with increasing the oxidizer mass flux, the relationship of regression rate vs. oxidizer mass flux for two kinds of fuels can be described by a power function and the exponents of power function for two kinds of fuels are 0.704±0.003 and 0.688±0.002, respectively. The fluorides coated nano-aluminum powder has certain promoting effect on the regression rate of the fuel and this effect is not changed along with the change of the oxidizer mass flux. In the whole studied range of oxygen mass flux, the regression rate of the fuel with fluorides coated nano-aluminum powder is about 13% higher than that of the fuel without additives. The theoretical specific impulse in vacuum and adiabatic flame temperature for two kinds of fuels reach to the largest value when the mass ratio of oxygen and fuel equals to 2.0. The addition of aluminum powder does not increase specific impulse of fuel in vacuum obviously when mass ratio of oxygen and fuel is in the range of 0.4-8.