Numerical prediction and evaluation of ice accretion and its impact on aerodynamic performance in aircraft design

Aircraft icing presents a critical challenge in aviation, profoundly affecting aerodynamic performance and flight safety. Beyond increasing drag and reducing lift, icing alters stall margins, disrupts control surface effectiveness, and increases the risk of boundary layer separation. The complex dynamics of ice accretion, the transition between forms like rime and glaze ice, and the influence on anti-icing heat transfer systems further complicate its prediction and mitigation. Existing methods for predicting the relationship between ice accretion and aerodynamic degradation are constrained by high costs, computational demands, and reliance on qualitative assessment, resulting in critical gaps in their applicability to complex three-dimensional scenarios and advanced aircraft designs. This thesis addresses this gap by introducing a novel, low-cost, validated methodology to estimate aircraft design performance under various icing conditions, enabling more efficient decision-making during the early stages of aircraft design. The cornerstone of this research is an innovative non-dimensional ice boundary perimeter parameter that quantifies changes in wing surface profiles due to ice accretion and assesses the resultant aerodynamic impacts. The study spans 2D and complex 3D icing scenarios, including horn, streamwise, and spanwise ridge formations. The effects of initial surface roughness, mesh resolution, and multi-shot icing methods on accreted 2D and 3D ice shapes are evaluated based on a commercial swept wing. Advanced numerical simulations, incorporating multiphase modelling, conjugate heat transfer, and mesh displacement techniques, are used to validate the proposed ice boundary perimeter parameter against existing experimental data and newly developed computational results. Additionally, the study examines runback ice formation on composite materials, analysing the impact of power density under varying icing and flight conditions. The findings establish a strong correlation between the ice boundary perimeter and aerodynamic penalties, providing a scalable and accurate means of assessing icing severity. By improving measurement techniques for complex ice shapes, this research enhances the development of efficient anti-icing systems and offers valuable insights for regulatory frameworks, contributing to improved aviation safety. This thesis significantly advances the understanding of icing phenomena and their aerodynamic effects, paving the way for future research, including parameter refinement for intricate icing scenarios and the application of machine learning models to predict aerodynamic penalties. The outcomes promise to contribute to safer, more efficient, and economically sustainable aviation operations.