Description: Key Technical Challenges: Modification of several physics-based and empirical models for unsteady flow combustors and connecting components for the specific conditions associated with the RDRE and linked together to form a single overall system modeling tool.\nApproach/Research Plan: Identify all sub-models to be included in overall model in consultation with partners; Complete initial validation of baseline RDRE CFD model; Complete development of sub-system models and validations; and, Complete overall system model and validation.\nDifferent/Complementary: AFRL-Edwards is the only organization to date that has tried to assemble a system level RDRE model. However, this model is still a work-in-progress as AFRL-Edwards does not have the modeling experience in unsteady flow combustion devices that is resident at NASA GRC. AFRL-Edwards has solicited GRC support in developing a performance model and anticipates being a significant user of the model after completion.\nNext Step: Contine ongoing relationship with our partners in the area of RDRE research and modeling.

Benefits: Goal: To develop a series of linked physics-based sub-component models to cover all the components of the RDRE engine.\nCapability Need/Knowledge Gap: Without such a model, it is not possible to calculate the overall vehicle-level benefits of the RDRE, nor is it possible to determine correct operating points for the combustor (inlet pressure, temperature, propellant phase) to direct ongoing experimental research activities.\nState-of-the-Art/Knowledge: While the RDRE combustor has been demonstrated by several organizations, there currently exists no cycle design tool that can estimate the performance of the entire propulsion system.