Design of Solid Propellant Grain for Boost-Sustain-Boost Rocket Motor Profile Using Different Propellants

Abstract

Research conducted starts from the basics of Solid fuel rocket motors (SRM). As SRM are used for various applications for their high reliability and simplicity. Shaped mass of solid fuel is known as propellant grain. As the design of a propellant grain plays vital role in solid rocket motor operation. In this study grain configurations are designed to produce boost-sustain-boost (thrust-time) profile. Three different configurations are used to obtain the required thrust-time profile. Boost-sustain-boost profiles of grain configuration using grain having different burning areas with internal burning and grain configuration in which burning takes place in two steps are compared using four type of propellants (DB, MDB, CMDB, Composite) and a grain configuration in which a grain producing dual level of thrust is used with the combination of six different burning rate propellants. In this study the 3-D grain burn back analysis of the propellant grain is performed. Solid modeling of the 3-D propellant grain is chosen as the design methodology for predetermined burn steps. Pro Engineering, Wildfire 4.0, CAD software is used as parametric modeling tool. By changing parameters (grain length, inner diameter, fin length etc) for each web step, new grain model is created and surface area is obtained which is used to compute chamber pressure and burn rate to predict performance. Results show that grain configurations with two step burning and grain producing dual level of thrust with different burning rate propellants combination are preferable. Comparison of propellants shows CMDB propellant is more efficient than DB, MDB, composite propellants and MDB-CMDB combination is preferable.