Validation of Actuator Disk Simulations of CROR Propulsion Systems at Low-Speed Flight Conditions

Kurzfassung

In the present investigation, a validation of the Actuator Disk (AD) model implemented in the DLR-TAU Reynolds-Averaged Navier-Stokes (RANS) solver is performed for the simulation of Contra-Rotating Open Rotor (CROR) propulsion systems. The analysis focuses on a 12x9 CROR in pusher con�guration at model scale and low speed conditions in isolated and semi-installed arrangements. The actuator disk computations are validated with unsteady computations (uRANS) of the system with rotating blades. For the modeling of the actuator disks, data bases of blade airfoils are computed in 2D to predict the forces produced by the blades at different radial stations of the disk. For this purpose, two approaches for the calculation of the blade forces are performed. The fi�rst approach considers the resulting velocity produced by the free stream velocity and the rotational speed, assuming that the free stream velocity is aligned with the rotor rotation axis. The second approach considers the e�ffect of a deviation of the oncoming flow approaching the rotor planes. For the validation of the model, rotor performance and wake velocity profi�les are extracted and a comparison of both numerical approaches is performed. The results obtained, show a very good agreement between the performance numbers obtained from both numerical methods uRANS and AD. Also a good representation of the flow in the propwake is obtained with the simulation using AD model compared with the uRANS simulation.