Experimental and numerical study on large droplets impingement characteristics of an aeroengine strut

To accurately characterize Supercooled Large Droplet (SLD) impingement on the windward surfaces of engine components, this study designed and constructed an impingement experimental system for an aeroengine strut. Using a dye tracing technique, the surface chroma distribution on a plaster test article was extracted and converted into relative water collection efficiency via colorimetric analysis. Based on the experimental data, a modified SLD impingement model was developed from the LEWICE and Honsek models and employed to numerically simulate the impingement characteristics. Subsequently, the effect of droplet diameter on the relative water collection efficiency was analyzed. Across all Median Volumetric Diameters (MVDs), the relative water collection efficiency consistently reaches a peak at the stagnation point. Downstream of the stagnation point, the droplet mass loss on the strut surface increases rapidly, while the relative water collection efficiency drops sharply, gradually decreasing to zero within the leading-edge region. Near the stagnation point (z/c <= 0.04), the mass loss coefficient increases with increasing MVD. Governed by splashing and rebounding, the relative water collection efficiency in this region reaches its maximum at MVD = 104 μm. Further downstream (z/c >= 0.04), droplet inertia dominates, maximizing both the relative water collection efficiency and the impingement limit at MVD = 230 μm. Across all conditions, the root-mean-square error between the numerical and experimental results remains below 15%. These results validate the accuracy of the modified model in predicting SLD impingement characteristics involving splashing and rebounding.