Experimental study on time-resolved 3D ice accretion shape measurements in large-scale icing wind tunnel

Aircraft icing can cause severe aerodynamic and flight mechanical effects, thus threatening aircraft flight safety. Understanding of aircraft icing, e.g., geometry shape of the ice accretion, is significant for its aerodynamic analysis, control methodologies, and continued design. In this study, a laser sheet scanning approach is developed to achieve the time-resolved geometry shape measurements of the ice accretion. By using the tridimensional calibration board consisted of two special checkerboard plates, all laser plane coefficients during laser sheet scanning could be obtained in advance. Then, based on the two-stage laser line extraction scheme that combined the Steger method with gradient centroid calculation, accurate positioning of the laser lines projected on the ice accretion surface was realized. The proposed approach is demonstrated in the large-scale icing wind tunnel tests of an airfoil model, conducted at the 3 m × 2 m Icing Wind Tunnel of China Aerodynamics Research and Development Center. Temporal evolution of the rime, mixed, and clear ice accretion shapes on the leading edge of the airfoil model was measured throughout the tests, respectively. The measurement at the end of ice accretion was compared with the results by a commercial 3D laser scanner, which showed highly consistent.