Comparison of Numerical Simulations with Experimental Data for an Electrothermal Ice Protection System in Appendix O Conditions

This paper provides information on the comparison of numerical simulations with experimental data for an electrothermal ice protection system with a focus on Appendix O [1] Freezing Drizzle (FZDZ) and Freezing Rain (FZRA) conditions. The experimental data is based on a test campaign with a 2D NACA23012 wing section in the RTA Icing Wind Tunnel in Vienna. 22 icing runs (all either unheated or in anti-ice mode) were performed in total and all residual ice shapes were documented by means of high-resolution 3D scanning. Unheated FZDZ and FZRA reference as well as heated cases with different heater configurations are presented. The experimental results are compared to numerical predictions from two different icing codes from AeroTex GmbH (ATX) and the University of Applied Sciences FH JOANNEUM (FHJ) in Graz. The current capabilities of the codes were assessed in detail and regions for improvement were identified. Overall, the codes were able to predict the ice shapes of both the unheated and heated cases with reasonable accuracy but both codes overestimated the thickness of the runback ice ridges throughout all cases. The biggest deviations in terms of the position of the ice accretions were seen on the lower surface; on the upper surface a better match was observed.