Multiphase Modeling of Solid Rocket Motor Internal Environment

Solid rocket motor (SRM) design requires thorough understanding of the slag accumulation process in order to: predict thrust continuity, optimize propellant conversion efficiency, predict coning effects from sloshing, and assess potential orbital debris (slag) hazard. Current state-of-the-art models for SRM environment do not have the capability to simulate the accumulation and dynamics of slag in SRMs as they rely on a Lagrangian particle approach that is only capable of predicting the location of accumulation. In this STTR effort, CFDRC will team up with Mississippi State University and Tetra Research to develop models for quantifying the effects of slag accumulation and dynamics on SRM performance. To enhance current slag modeling capabilities, an Eulerian-Lagrangian approach to accurately model a slag-phase is proposed, in which Lagrangian particles can be converted to an Eulerian description and vice-versa. The Phase I project aims at developing the basic numerical model for the transport and accumulation of a slag-phase in Loci/CHEM. The multiphase framework, comprising of gas-phase, a dense slag-phase, and Lagrangian particles representing aluminum and alumina, will be developed and demonstrated in the Phase I effort with a TRL starting at 2 and ending at 3. In Phase II, the models will be extended and validated to provide an accurate numerical approach for slag dynamics that incorporates many of the physical phenomena present during SRM operation, including the transfer from Eulerian to Lagrangian description of slag at burnout, increasing the technology readiness level by the end of a Phase II project from 3 to 5.

The proposed physics-based multiphase model for the SRM environment will find a multitude of applications at NASA and for DoD and industry customers. The applications include: (1) Accurate modeling of slag accumulation during the operating of an SRM, (2) Quantitative analysis of the effect of slag accumulation on propellant conversion efficiency (3) Analysis of sloshing and the potential effects on SRM conning, (4) Assessment of slag as a potential debris hazard, and (5) Assessment of new concepts for SRM design and trade studies. At the end of Phase II, a well-validated suite of tools will be available to NASA and its government contractors to better understand SRM combustion and dynamics in large-scale solid rocket motors.

Companies such as Aerojet-Rocketdyne and Lockheed Martin can benefit from the advanced SRM modeling capabilities in the same way NASA can. The potential of understanding slag accumulation/dynamics in SRM can aid in designing high performance-cost ratio systems. In addition, the proposed slag model will have the capability to account for slag after SRM burnout, time at which slag poses as a potential hazard. This is of particular interest to the Missile Defense Agency (MDA). The transport of slag during operation of the SRM and after burnout are of critical importance to MDA to understand the radiation signature of the plume at burnout. The developed tools will be directly apply to these applications.

This is early/mid-stage (TRL 3) — the most realistic path in is NASA SBIR/STTR, which funds small businesses and research institutions to develop technology aligned with NASA's needs (equity-free, phased funding). Check whether a current SBIR/STTR solicitation topic overlaps with this project's technology area, or contact the project directly (above) to ask.

None of these are guaranteed paths for this specific project — TechPort itself doesn't have an "apply" button. Reaching out to the contact(s) above with a specific question is usually the fastest way to find out what's actually open.