Novel Approach for Characterizing Solid Rocket Motor (SRM)

Abstract

To characterize SRM, the motor needs to be tested on a static test rig and certain performers indicators evaluated. In this study, the thrust with time from the SRM was acquired via a Digital Acquisition (DAQ) System and saved in Microsoft Excel^® format(.csv). These thrust and time of the tested motor were then imported into MATLAB^® for the purpose of computing burn time, maximum thrust, average thrust, total impulse, specific impulse and chamber pressure of the motor. The specific impulse and combustion chamber pressure for the SRM were computed in a novel approach which we call Pseudo-numerical approach (combination of experimental result with numerical computation). In this approach, first, we modelled the depleting propellant mass in the combustion chamber with a novel mathematical expression. This novel expression was then used in computing specific impulse of the SRM. Second, the total surface area of the propellant grain was modelled as a hollow cylinder with depleting dynamics during motor operation, in a similar manner with the propellant mass. Third, multiplying the reciprocal of the propellant grain surface area with the experimental force gave use the pseudo-numerically computed chamber pressure. The pressure trend of the SRM obtained was also compared to those in well-established literature, thus, the pseudo-numerical approach put forward proves to be effective.