Advanced Flow Analysis Tools for Transient Solid Rocket Motor Simulations

The challenges of designing, developing, and fielding man-rated propulsion systems continue to increase as NASA's mission moves forward with evolving solid propulsion requirements. Recent developments in simulating solid rocket motor environments include Lagrangian particle tracking, particle combustion models, dynamic particle drag and breakup models, and two phase impingement phenomena. These advances are demonstrating success in numerically simulating solid motor environments, but evolutionary innovations leading to more realistic simulations are required. In particular, transient ignition phenomena, such as grain surface heating, initiation of surface reactions, and transition to steady burning, have not yet been addressed. Consideration of these transient flow aspects is extremely important for analyzing ignition delay, pressure buildup, nonuniform grain recession, and overall combustion behavior. Our research will combine existing two phase flow tools for solid motors with a grain heating and ignition model to produce software tools for simulating transient ignition phenomena and the subsequent flow development. These products will ultimately provide NASA with the important capability to simultaneously analyze solid propellant ignition and combustion, heat transfer, and grain burnback within a unified framework. We will demonstrate feasibility using a two phase solid propellant ignition model for a simple grain shape in the TRL range of 3-4.