Numerical Simulation of Aircraft and Variable-Pitch Propeller Icing with Explicit Coupling 2019-01-1954
A 3D CFD methodology is presented to simulate ice build-up on propeller blades exposed to known icing conditions in flight, with automatic blade pitch variation at constant RPM to maintain the desired thrust. One blade of a six-blade propeller and a 70-passenger twin-engine turboprop are analyzed as explicitly-coupled stand-alone components in a multi-shot quasi-steady icing simulation. The thrust and swirl produced by the propellers provide the loading distribution for their actuator disk surrogates mounted on the aircraft. The thrust that must be generated by the propellers is obtained from the drag computed on the aircraft. The total icing exposure time is subdivided into 30-second shots. The flight conditions are typical for a 70-passenger twin-engine turboprop in a holding pattern in Appendix C icing conditions: 190 kts, altitude 6,000 ft, air static temperature -16 ˚C, LWC 0.3 g/m3 and MVD 20 microns. The iced geometries are automatically remeshed at each shot using ANSYS FENSAP-ICE and Fluent Meshing tools. Solutions for the 2-meter blade are computed in a periodic domain to reduce computational costs. The pitch variation is a semi-automated process where a limited pitch sweep is computed at each shot to find the appropriate blade angle. The rotation rate is set at 850 rpm, a typical operating condition for this flight envelope. The preliminary results show a variation from rime to glaze ice with prominent horns at the blade tip, and a 5.4% loss of thrust after 4 minutes of icing (8-shots).
Isik Ozcer, Guido S. Baruzzi, Miraj Desai, Maged Yassin
International Conference on Icing of Aircraft, Engines, and Structures