High-Lift Propulsive Airfoil with Integrated Crossflow Fan

Abstract

A concept for embedding a crossflow fan into a thick wing for lift enhancement and thrust production is proposed. The design places a crossflow fan propulsion system with raised inlet near the trailing edge of the wing. Flow is drawn in from the suction surface, energized, and expelled out the trailing edge. The integration of a crossflow fan within a modified Gottingen 570 airfoil section with 34% thickness to chord ratio is developed and simulated using the commercial CFD software Fluent. Unsteady sliding mesh calculations are used to visualize the flowfield and calculate fan performance and airfoil lift coefficient. The results of the CFD work show that the jet leaving the fan fills up the wake behind the airfoil, whereas the suction effect produced by the fan virtually eliminates flow separation at high angle of attack, yielding very high-lift coefficients. A system level analysis demonstrates the benefits of using an embedded crossflow fan for distributed aircraft propulsion. The system analysis yields tradeoffs between various design parameters and provides a basis for preliminary crossflow fan airfoil design.