Numerical Simulation of Ice Crystal Accretion Inside a Turbofan Core Stator 2019-01-2017
A CFD simulation methodology to calculate blockage due to ice crystal icing of the IGV passages of a gas turbine engine is presented. The computational domain includes the nacelle, full bypass and the air induction section up to the 2nd stage of the low-pressure compressor. The model is a geared turbofan whose fan rotates at 3800 rpm and the compressor rotor at 8000 rpm. The flight conditions are based on the FAA FAR25 Appendix-D for a cruising altitude of 28000 ft., where the static temperature is 240 K, crystal MVD is 50 microns, ICC is 3.82 g/m^3 and the relative humidity is about 40%. The air speed is set at 0.78 Mach. Crystal bouncing and re-impingement is considered in the calculations, along with variable relative humidity and crystal melting due to the temperatures rise within the engine core. Crystal sticking and erosion effects are modeled using analytical methods. Total time of icing is set at 10 minutes. The ice shapes that accrete on the IGV passage are calculated in a multi-shot, multistage approach, with frequent updates of the computational grid to reflect the changes in the surfaces and blockage in the domain. The starting number of grid points in the entire system is around 8 million and increases with the remeshing of the iced surfaces.
Shezad Nilamdeen, Vinod Singh Rao, David Switchenko, Jeyatharsan Selvanayagam, Isik Ozcer, Guido S. Baruzzi
International Conference on Icing of Aircraft, Engines, and Structures