Icing characteristics of full-scale multi-element configurations of large aircraft: Computation and experiment

A study on ice accretion characteristics of the full-size tri-element airfoil of typical large airplane was conducted using a combined approach of numerical and experimental methods. Numerical techniques specifically developed for simulations of icing on multi-element airfoil structures were implemented on the NNW-ICE software platform. These techniques include a highly efficient Lagrangian method for droplet collection, an icing simulation method featuring the unsteady flow of water film, and a reconstruction method for calculating the evolution of volume grids and ice layers in multi-shot icing simulations. Then, the full-size tri-element airfoil was utilized in simulations using the NNW-ICE software, as well as in experimental tests conducted in the 3 m × 2 m large-scale icing wind tunnel at the Chinese Aerodynamics Research and Development Center. A detailed analysis was performed on the icing characteristics of the back of the slat wing. The results indicate that ice can unexpectedly accumulate on the lower side of the flap wing and the back of the slat wing, in addition to the accumulation observed on the windward leading edge of both the slat wing and the main wing. This study revealed for the first time that the ice on the back of the slat wing exhibits a unique double-ridge ice shape, and the formation mechanism of the ice shape was interpreted through numerical analysis. The results and findings can provide valuable references for the design of high-lift and anti-/de-icing devices in the aircraft.