Experimental evaluation of flow distortion at NGCTR optimized air intake full scale model

Abstract

Within the Clean Sky 2 Fast Rotorcraft platform, a Next Generation Civil Tilt-Rotor (NGCTR) Technology Demonstrator is being developed. Within the related TRINIDAT project the key driving aerodynamic choices of the engine air intake configuration are being investigated. A wind tunnel model has been successfully designed and manufactured for full-scale intake testing of modular intake configurations. The model is comprised of a nacelle, modular intake duct, rotatable spinner hub (rotor head) and wing part including deflectable aileron. In order to assess the flow quality at the Aerodynamic Interface Plane (AIP), a novel highly instrumented rotary rake has been designed. The model also includes a large amount of static pressure taps on wing and intake duct surfaces. The results of a wind tunnel test with the basic intake configuration in the DNW-LLF have been published in an earlier paper and yield a large database containing basic intake performance and sensitivities for the full flight envelope [14]. The present paper presents the results of an optimized intake configuration which has been successfully tested in a second TRINIDAT entry at the DNW-LLF. The adopted scaling methodology is explained. The 6 x 6 m2 test section allowed to test the full-scale model at ????=0.40 which is nearly cruise Mach number. The test program included variations in angle of attack, sideslip angle, aileron deflection and suction mass-flow rate. Post-processing of the test data yielded a large database including flow distortion parameters based on the total pressure field and the velocity field in the AIP. A comparison of key flow distortion parameters and static pressure distributions between optimized and basic intake showed that the optimized intake overall features significant improvement of the flow quality. For the aircraft mode an averaged reduction in ????60?????? of 74% has been realized. The development of unsteady pressures along the optimized intake duct including AIP has been characterized as well.