CFD Modeling and Simulation for Ducted Rotor Test Stand Design

The test-stand is designed to independently measure force and moment loads on the duct and the rotor of a ducted rotor system. The wake of the rotor interferes with the structural parts of the test-stand and is expected to impact the measurement of loads. Computational Fluid Dynamics (CFD) modeling of ducted rotor test-stand is carried out to estimate the effects of the test-stand structure and to determine configuration to minimize the impact. A 4-blade rotor of NACA0015 airfoil cross section in a representative duct was modeled along with the test-stand. Effects of the test-stand structure were estimated by comparison to an ideal configuration of isolated ducted rotor and with the ducted rotor mounted upside down on the test-stand. Comparing the results at several rotor speeds and blade pitch showed that the rotor thrust was increased by up to 6% due to the interference of the test-stand while the torque increased by up to 3%. The computed thrust for the inverted ducted rotor agreed better with the isolated rotor. The effects of the test-stand on the duct thrust were within the computational error margin.