Numerical Demonstration of the Humidity Effect in Engine Icing 2019-01-2015
The importance of the variation of relative humidity across turbomachinery engine components for in-flight icing is demonstrated by numerical analysis. A species transport equation for vapor has been added to the existing CFD-Icing methodology for the simulation of ice growth and surface water flow on engine components that are subject to ice crystal and mixed-phase icing. This PDE couples the heat and mass transfer between droplets, crystals and air, adding the cooling of the air due to particle evaporation to the icing simulation, increasing the accuracy of the evaporative heat fluxes on wetted walls. Two validation cases are presented for the new methodology: one showing a 1.6 ˚C reduction in the outflow total temperature of the air in a wind tunnel due to the water spray at the inflow boundary. The second case shows improvements in the simulated ice shape compared with the NRC of Canada crowned cylinder experiment. For the simulation technology demonstration, turbofan icing scenarios with inflow relative humidity varying between 30 and 100% are simulated using a generic engine geometry that includes the nacelle and the first stages of the compressor. The inclusion of vapor transport and local relative humidity provide important additional modeling functionality and increased simulation accuracy.
Yue Zhang, Isik Ozcer, Shezad Nilamdeen, Guido S. Baruzzi, Jeyatharsan Selvanayagam
ANSYS Inc, ANSYS Inc.
International Conference on Icing of Aircraft, Engines, and Structures