Advanced Particle Treatment in Modeling Rocket Exhaust Plumes

The proposed Phase I effort involves the formulation of improved models to accurately simulate the particles that are present in rocket exhaust plume flowfields with the goal of obtaining improved plume signature predictions. While the modeling of the exhaust plume flowfield is a relatively mature technology, the sub models that are utilized to describe the behavior of the particle phase are in need of improvement. In Phase I, methods will be investigated to replace the current"binning"approach that is utilized to approximate the particle size distribution and the practicality of employing a probability density function (PDF) method will be assessed. Another area where improvement is needed is in the modeling of soot produced in hydrocarbon based liquid propellant systems. The current modeling of the combustion of soot as a"pseudo gas"has been shown to be inadequate and models that treat the combustion in the solid phase will be investigated. The resulting product will be a first principles based CFD model that can capture these complex processes. This is a critical requirement for the accurate generation of active and passive signatures.