Two-way Flow Coupling in Ice Crystal Icing Simulation 2019-01-1966
Numerous turbofan power-loss events have occurred in high altitude locations in the presence of ice crystals. It is theorized that ice crystals enter the engine core, partially melt in the compressor and then accrete. This may lead to engine rollback, or shed induced blade damage, surge and/or flameout. The first generation of ice crystal icing predictive models calculate particle trajectories and accretion growth rates using a single flowfield for which there is no accretion on the test piece. Recent work completed at the University of Oxford has created an algorithm to automatically detect the edge of accretion from experimental video data. Using these accretion profiles, numerical simulations were carried out at discrete points in time using a manual meshing process. This work showed that flowfield changes caused by a changing accretion profile had significant effects on the collection efficiency of impinging particles, ultimately effecting the mass of accreted ice and its shape for certain operating conditions. The paper discusses the development of the ICICLE numerical ice crystal icing code to include a fully automated two-way coupling between the accretion profile and flowfield solution, to account for these effects. The numerical strategy; geometry redefinition, mesh update and flowfield solution is discussed, followed by a comparison to experimental ice accretion of a simple 2D geometry. Finally, the conditions at which flow field updating is required is discussed, along with other conditions at which the increased computational cost outweighs the increase in accuracy.
Jonathan Paul Connolly, Matthew McGilvray, David Gillespie, Alex Bucknell, Liam parker, Geoffrey Jones, Benjamin Collier
University of Oxford, Rolls Royce
International Conference on Icing of Aircraft, Engines, and Structures