Abstract:
This paper presents a three-dimensional simulation of the ignition transients within the Space Shuttle Reusable Solid Rocket Motor (RSRM) using the Rocstar 3 simulation code, a tightly coupled, multi-physics tool developed at the Center for Simulation of Advanced Rockets (CSAR). The simulation utilizes a detailed 3-D geometry of the RSRM, including its 11-point star grain, joint slots, and submerged nozzle. A simple heat transfer model is employed to calculate propellant heating from hot igniter gases, and a 1-D dynamic burn rate model is applied to capture transient behavior once the propellant reaches its critical ignition temperature.
The study focuses on a fluids-only simulation where the propellant is assumed to be rigid. The resulting head-end pressure history is compared against data from the TEM-6 test firing and the Space Shuttle Design Data Book, showing good agreement in capturing key features such as the ignition delay and subsequent rate of pressure increase. Similarly, the axial pressure profile along the motor's axis at 800 ms is compared favorably with experimental data from QM-7 and QM-8 test firings. Discrepancies, notably a longer simulated delay before pressurization, are attributed to the omission of radiative heating, which is expected to be a dominant heating source in certain regions. The paper concludes by noting that a fully coupled fluid/structure/combustion simulation is in progress.
