Combustion performance with ap and boron addition in staged hybrid rocket

This study investigated the effect of ammonium perchlorate (AP) and boron addition on controllability of the combustion temperature in fuel-rich effluent and system specific impulse. In addition, a series of combustion tests was carried out to analyse and evaluate the effect of boron addition on fuel regression rate and radial temperature profiles. To keep the hybrid rocket engine advantages, upper limit of AP and boron contents in solid fuel was set to be 15 and 10wt% respectively. The results suggested that AP addition proved to be very effective in controlling the effluent temperature. Not only that, it also offers less injected oxidizer mass flow, and resulted in less O/F variation, and less combustion pressure while producing the same combustion in temperature fuel-rich effluent. With boron addition, it also provided more uniform radial temperature distribution. Also, boron addition increased specific impulse by 6.8-13.7%. Secondary combustion using different solid fuels showed a decrease in c* efficiency with increasing boron content in solid fuel. Combustor length and combustion pressure were introduced to improve the combustion of boron particles, however, combustion efficiency was decreased with increasing combustion pressure and combustor length for given test conditions.