Study on Large Droplet Impingement Characteristics of a Rotating Conical Spinner Model

Accurately predicting the motion and impingement of supercooled water droplets is crucial for analyzing ice accretion and anti-icing. This study designed and constructed an experimental setup to analyze large droplet impingement characteristics. Tests were conducted on a rotating conical spinner model using a dyeing method. Chrominance values relative to the stagnation point were obtained via colorimetric analysis and converted into the distribution of the relative local collection coefficient on the spinner surface. Calibrated against the experimental data, a corrected model for supercooled large droplet (SLD) impingement was derived from existing semiempirical models and applied to simulate impingement on the rotating spinner. The results show that the local water collection coefficient peaks in the spinner's stagnation zone and plunges to about 0.6 on the downstream conical surface, where it remains nearly constant with slight splashing or rebounding before dropping abruptly at the cone's tail. The local collection coefficients for median volumetric diameter (MVD) of 146 and 230 μm are very close across the surface, and both are higher than the coefficient for MVD = 71 μm. Under the conditions of this study, the distribution of local collection coefficients for large droplets is consistent across the three incoming velocities and their corresponding rotational speeds, showing no significant variation.