Development of inert propellant to simulate different properties of HD1.3 class large size Solid Rocket Motors

Abstract. The processing of solid rocket motors is hazardous and expensive. The development of propellant compositions that replaces oxidizers with inert material will enable the development of efficient, safe, and sustainable propulsion systems. However, it presents significant challenges in meeting essential rheological, mechanical, structural and physical properties required for propulsion applications. Selection of Inert material is done which is having comparable physical properties i´e particle size distribution (PSD), density and hardness. Potassium chloride (KCL) with a special chemical coating (fert flow) is selected to develop the inert propellant for simulation of HTPB/TDI based HD 1.3 class propellant. Different experiment is done to resemble the parameters like viscosity of the slurry, modulus, % elongation, density and hardness of propellant. Achieving the desired viscosity is vital to ensure proper flow characteristics of propellant slurry, particularly in processing of large size rocket motor as the total quantity of the propellant is to be casted within penetrametric pot life to get defect-free quality propellant grain. Density of the inert formulation is controlled to ensure that it achieves the required energy density for effective propulsion. This is achieved by optimizing PSD of KCL. Mechanical strength of the propellant is required to sustain different types of loads like transportation and acceleration loads. Present study is to optimize Inert propellant Composition which should contains 85%-86% solid loading and 14%-15% binder system. Factors which are predominantly tailoring the mechanical and rheological properties are the weight percentage of Plasicizer, Crosslinker, Binder (HTPB) and Curator (TDI). In this study composition of inert propellant is successfully optimized to meet all the rheological, mechanical, structural and physical properties. The resulted composition has extensive use in space exploration and defence systems.