Ultra pure ammonium perchlorate T-burner pressure coupled response at 500, 1000 and 1800 psi

Abstract

This paper contains initial results of pressure coupled combustion response T-burner measurements for pressed pellets of ultra pure ammonium perchlorate. Photos of the 200 micron AP particles before pressing and from a crumbled pellet are shown. AP particles do not shatter when pressed but deform to fill the voids. Pellets were pressed with a donut die to allow 0.453 inch hole in center required for pressure pulsing. The pellets were inserted in custom sample holders with tight tolerances. The pellets were tested at frequencies from 130 to 2500 Hz at pressures of 500, 1000, and 1800 psia. Although some tests were pulsed, the oscillations were spontaneous under many conditions. Spontaneous oscillations are preferred because of a smaller disturbance of the combustion zone. At 1000 psi the AP oscillated spontaneously with growth rates of 3 1/s near 1000 Hz, and at 500 psi the spontaneous growth rates were 1 1/s near 140 Hz. At lower pressures of 300 and 400 psi samples would occasionally extinguish, so testing was discontinued at low pressures. At 1800 psi, growths and decays were similar below 900 Hz, although the data appears rather scattered. The general trend from 500 to 1000 psi agrees with Beckstead's model calculations that the response magnitude decreased from 4 to 2.5 and the resonant frequency increased from 150 to 1000 Hz. The AP data is compared with HMX and RDX.