ATHENAI · Aerodynamic Testing of Helicopter Novel Air Intakes

The project is aimed on enhancing the aerodynamic performance of novel engine air intake concepts for helicopters by shape optimization. Comprehensive wind tunnel tests are performed on a full scale model of a helicopter fuselage section comprising engine cowling and air intake flow passages. The main effort is on two wind tunnel campaigns to analyze in detail the aerodynamic characteristics of three baseline air intake configurations and several design variants. The design modifications concentrate on flow guiding elements like fillets, vanes, spoilers and scoops. The measurements include total pressure and three component velocity fields at the aerodynamic interface plane (AIP) to quantify total pressure losses and inflow distortions. For optimum engine performance, such values have to be minimized by geometry adaptation. Setting up an extensive data base, steady and unsteady surface pressures on cowling and air intake regions are recorded simultaneously to the AIP measurements and correlated with field measurements of mean and fluctuating velocities documenting the incoming flow. A new wind tunnel model consisting of the extended fuselage cowling part and all air intake components and flow passages is designed, manufactured and instrumented to carry out the experiments. The model is of high modularity to easily exchange the various air intake components. Data analysis and evaluation will provide highly required guidelines for helicopter air intake design.