Experimental and Numerical Investigation of a Contra Rotating Open-Rotor Flowfield

Abstract

Contrarotating open rotor propulsion systems have seen renewed interest as a possible economic and
\nenvironmentally friendly powerplant for future transport aircraft. While the potential efficiency benefits are well
\naccepted, concerns persist regarding the probable rotor-to-rotor interaction-driven noise penalty this type of engine
\nwould have in comparison to modern ducted turbofan engines. This paper presents results of a collaborative
\nexperimental and numerical study to quantify and study in-depth the complex flowfield of a generic contrarotating
\nopen rotor model at wind-tunnel scale. The model has 10 front blades and 8 aft blades, with blade design similar to
\nmodern propellers for high-disk loadings. The comparison of flow visualization results obtained through the use of
\nmodern stereoscopic particle image velocimetry and unsteady Reynolds-averaged Navier–Stokes simulations helps
\nto improve understanding of the interactions of front-rotor-blade wakes and tip vortices with the aft rotor, which is
\nan important aspect to guide the design of future efficient and quiet contrarotating open rotor engines. The generally
\ngood match between the experimental and numerical slipstream results gives confidence in the utility for their
\nanalysis capabilities in this field.