Validating a Novel Theoretical Expression for Burn time and Average Thrust in Solid Rocket Motor Design

Abstract

A major application of solid propellants is in gun propulsion systems and rockets. The performance of a rocket depends greatly on the design of the solid propellant that meets a specific mission. Performance characteristics such as the burn time, burn rate, average thrust, specific impulse, characteristic velocity, etc., are basic design parameters that will determine the nature of the trajectory and maximum altitude attained by such rocket. The main objective of this study, is to derive a novel analytical expression for burn time  and average thrust as a function of grain length and web thickness and compare experimental results from a static test bed with that of the analytically formulation. Here, a Sugar propellant (SP), sorbitol (C6H14O6) consisting of an oxidizer, potassium nitrate (KNO3), is locally propounded. In this study, five Solid Rocket motors (SRM) are under investigation, bate grain geometry were implemented and were subjected to a static thrust test. Data from the static thrust tests were acquired via a Digital Acquisition System (DAQ) and imported into MATLAB environment for the time verse thrust profile plot and other computations. The mathematically derived formulations for the burn time and average thrust gave a good correlation with experimental values for all the SRMs, with errors of less than 10 per cent.