Effects of Solid Propellant Cases on the Thermal Response of Nozzle Liner

The thermal response characteristics of nozzle liner for a solid rocket motor applying highly aluminized PCP or HTPB propellant with slotted tube grain have been investigated. The SEM photographs of aluminum oxide particles taken from nozzle liner show that the PCP propellant with the finer and less contents of oxidizer can offer greater possibility for increasing aluminum agglomeration than the HTPB propellant. The PCP propellant shows locally greater mechanical erosion at 4 circumferential areas of the nozzle entrance in line with grain slot due to the impingement of large particles, but the HTPB propellant shows greater thermochemical ablation at the nozzle blast tube, the throat insert and the exit cone because of relatively much more mole fraction of in combustion gases.