Modelling and Simulation of Mixed Phase Ice Crystal Icing in Three-Dimensions

High altitude ice crystals have led to instances of ice accretion on stationary compressor surfaces in aeroengines. Rollback, surge and stall events are known to have been instigated through such accretions due to aerodynamic losses related to ice growth, damage and flameout due to ice shedding. The prevalence of these events has led to a change in certification requirements for icing conditions. Development of accurate numerical models allows the costs of certification and testing to be minimised. An in-house computational code was developed at the Oxford Thermofluids Institute to model glaciated and mixed-phase ice crystal icing. The Ice Crystal Icing ComputationaL Environment (ICICLE) code, comprises a frozen 2D flowfield solution, Lagrangian particle tracking, particle heat transfer and phase change and particle surface interaction modelling. In this paper the ICICLE code is developed into a 3D modelling environment, including 3D particle tracking and modelling of particle wall interactions. This work is validated through comparison to ice crystal icing experiments conducted at the NRC Research Altitude Test Facility (RATFac), using an engine representative compressor stator vane as the test article. Capturing the spanwise secondary flows present on the stator vane is found to be necessary to quantify the distribution of ice accretion and erosion. Comparison with stator vane experimental results shows the effectiveness of 3D modelling. Further computational solutions are presented for a periodic end-walled and cantilevered stator vane solution to highlight the difference between quasi 3D flowfield modelling and representative full 3D cases.