Combustion of micron-aluminum and hydrogen peroxide propellants

Abstract

In this paper we report the burning rate characteristics of hydrogen peroxide and micron-aluminum propellants. Theoretical calculations show that the sea level specific impulse of this simple binary mixture is comparable to standard composite propellant. In addition, the aluminum particle size, hydrogen peroxide concentration, and mixture ratio can be adjusted over a flat peak performance regime to attain specific thrust profiles and durations. We measured the burning rates in a windowed pressure vessel at pressures ranging from 7 to 14MPa. Results show that mixture burning rates span from 0.5 to 4.5cm/s at 7MPa with power law burning rate pressure exponents ranging from 0.33 to 1.07. In this study, we focus a statistical analysis on the determination of the most influential variables affecting the burning rate and apply a thermal analysis to determine the combustion regimes of these mixtures. The statistical analysis provided a multivariate regression model for the logarithm of the burning rate with a correlation coefficient of 0.93. The model suggests aluminum diameter is the most important factor affecting the overall burning rate, and H2O2 concentration as the most influential variable on the burning rate pressure dependence. The burning rate dependence on theoretical combustion temperature shows two distinct combustion regimes attributed to kinetic and diffusion controlled combustion. A simple thermal analysis confirms the experimental burning rate pressure dependence observed for these two regimes.