Experimental and Numerical 3D Ice Accretion on Generic Test Model

In-flight icing can pose a significant risk to aircraft safety. For this reason a mix of numerical tools, wind tunnel tests and flight tests is generally applied during an aircraft or system development and certification process. In the past 50 years, extensive 2D data from wind tunnel tests have been generated, which is highly beneficial for code validation. The 2D simulation tools are reliable and accepted by certification agencies when applied correctly, but they cannot be applied to regions where significant 3D effects are present. Thus, there is also a need for high quality 3D standardized wind tunnel data specifically generated for numerical code validation. The 3D-ICESIM project aims to create an experimental database from icing wind tunnel tests to be used in 3D icing code development and validation. A generic test model was designed to include 3D features such as water impingement shadow and enhancement zones, complex curvature and abrupt geometry changes. The model was tested in icing conditions from the CS-25 Appendix C envelope and Freezing Drizzle conditions from CS-25 Appendix O. All ice shapes were photographed and 3D scanned. The data were then further applied as an assessment tool to improve the in-house icing code from AeroTex GmbH. This paper provides selected results from the experimental test campaign, together with simulated results from the latest version of the code. Rime ice accretions across a range of components show a good match to the experimental data, including in overall ice distribution, thickness and mass. For the larger glaze ice shapes the current single-step accretion process does lead to a larger difference to the experimental data, although general features are still well matched.