Actuator Duct Model of Turbomachinery Components for Powered-Nacelle Navier-Stokes Calculations

Abstract

An actuator duct model was installed into the WIND Navier-Stokes code. With this model, flow through fan rotors and fan exit guide vanes can be simulated without blade geometry. Flow turning, total pressure and total temperature changes across blade rows are controlled by body forces added to the Navier-Stokes equations. This model provides an affordable and relatively accurate prediction of a three-dimensional flow field through rotor and stator blade rows. A NASA Stage 35 compressor and a NASA 22 test rig flow were analyzed to quantify the ability of the actuator duct theory to represent blade rows. Favorable comparisons between predicted and measured total pressure, total temperature and swirl profiles indicated that the actuator duct logic was correctly installed in the WIND code. Comparisons of inlet separation angle-of-attack were made between test data and predictions using the actuator duct theory. The WIND code with the actuator duct model predicted higher separation angle-of-attack by an average of 2° for different fan speeds. The effect of the rotor on inlet flow separation was also determined by comparing the predictions of a flow-through nacelle with the predictions using the actuator duct to simulate the rotating fan. The comparison shows that the presence of the rotor increased separation free angle-of-attack over the flow-through nacelle which is consistent with the observation from the experiment. NOMENCLATURE