Physics-Based Aeroanalysis Methods for Open Rotor Conceptual Design

Operating costs and fossil fuel consumption of civil transports can be reduced through use of efficient counter rotating open rotor (CROR) propulsion systems, thereby addressing both key industry needs and long-term NASA technical goals. To develop such next-generation systems, multiple design variables must be assessed efficiently within a conceptual design software environment. A blend of physics-based, mid-fidelity tools featuring low CPU and ease of setup can provide this capability. Phase I built on an established, highly efficient lifting surface free wake model, the CDI CHARM analysis, and also began initial development of a novel variant of the CDI Cartesian Grid Euler (CGE) model to yield fast-turnaround, low- mid fidelity tools well suited to this requirement. Phase I involved several key upgrades to CHARM and preliminary validation on representative CROR designs. Regarding CGE, formulation of the new rotating frame and multirotor capability has been largely completed, and demonstrations of single rotor modeling are complete. Phase II will entail: additional upgrades to the CHARM rotor blade and airfoil models for improved fidelity; completion of implementation of the CGE analysis for CROR cases; integration of the two models into a unified CHARM-CGE AeroAnalysis (C2A2) architecture; and extensive validation and operational testing.