Determination of the Internal Ballistic Properties of Solid Heterogeneous Rocket Propellants

This paper describes the determination of the internal ballistic properties of tubular, solid heterogeneous rocket propellant (SHRP) charges based on hydroxyl terminated polybutadiene (HTPB) binder. The SHRP charges were screened (inhibited) on their external cylindrical surfaces and inserted into a laboratory rocket motor (LRM). These determinations originated from theoretical considerations and were developed using experimental measurements from static firings of SHRP charges in an LRM. Due to the design of the SHRP charge, its burning process began from the inner cylindrical surface and from both ends of the ring surfaces. The initial temperatures (Tp) of the SHRP charges tested were 233, 288 or 323 K in single static firing runs. On the basis of the pressure (p) of the combustion products of the SHRP vs. time (t) of the LRM operation, the dependence of the burning rates (rb) of the SHRP charges on (p) and on (Tp), and also the (rb) sensitivity to changes in (p) and (Tp), were determined by means of the indirect method.