Pressure deflagration limit of solid rocket propellants: Experimental results

Abstract

The burning of solid rocket propellants at pressures above and below the pressure deflagration limit (PDL) has been studied experimentally to obtain more details about the propellant combustion behavior in this critical pressure range. This work essentially is devoted to devising an experimental procedure to measure the PDL value with good reproducibility and to check its dependence on the operating conditions and propellant nature. Comparisons between different go/no-go techniques are presented, showing the chosen procedures to yield different results. Several solid rocket propellants have been tested (metalized and nonmetalized composite propellants, catalyzed double-base propellant). The results show a strong decrease of PDL for increasing cross-sectional area of the propellant sample and the trend, for higher sections, evinces an asymptotic PDL value depending only on the propellant nature as its intrinsic property. The external energy addition tends to decrease the PDL, but a minimum pressure value below which burning regime is not possible was still found. The experimental evidence shows that any operating conditions or physical-chemical propellant properties which increas the propellant burning stability yield a lower PDL. Comparisons with results obtained by other researchers validate this trend.