Development of a Digital Inline Holography Technique to Characterize Airborne Supercooled Water Droplets and Ice Crystals for Aircraft Icing Studies

Atmospheric icing on aircraft surfaces represents a significant aviation hazard that compromises flight safety and aerodynamic performance in cold weather conditions. Precise measurement of supercooled water droplets and ice crystal characteristics in cold environments is essential for accurate ice formation prediction. This study presents a comprehensive experimental investigation to develop an advanced digital inline holography (DIH) system capable of differentiating and characterizing supercooled water droplets and ice crystals within an icing research tunnel. The DIH system measures critical particle characteristics including liquid water content (LWC), median volume diameter (MVD), ice water content (IWC), and particle size/shape distribution. System validation was performed using standard NIST particles. Additionally, we propose a novel method for distinguishing between supercooled water droplets and ice crystals based on DIH measurements.