HMX and RDX T-burner pressure coupled response from 200 to 1000 psi

This paper contains initial results of pressure coupled combustion response T-bumer measurements for pressed pellets of HMX and RDX. Pellets of pure oxidizers were pressed with a donut die to allow 0.45 inch hole hi center required for pressure pulsing. The pellets were burned in T-burner pipes of length 10, 15, 22, 36, and 50 inches at pressures of 200, 500 and 1000 psi. The data from RDX and HMX show similar high frequency response at 1000 psi, but HMX had higher response at 200 psi and low frequency. As the pressure decreased, HMX oscillated spontaneously with growth rates of 1 to 4 sec" at 200 psia. RDX was slightly stable at 200 psi with growth rates of 0.7 sec". At 1000 psi for HMX the growth rates ranged from -1.6 to +4 sec", while for RDX they ranged from -8 to 9.5 sec". The RDX positive values were at 2000 Hz, which was unexpected. This data is of special interest to instability modelers, especially those doing transient monopropellant modeling as there has not previously been any pure ingredient pressure coupled response data.