Cross-functional Icing Particle Characterization using Optical, Resistive and Mechanical Measurement Techniques in a Wind Tunnel

Aircraft engine icing is one of the major safety-of-flight concerns in aviation industry. Number of engine icing events are reported each year, emphasizing the importance of continued research, testing, and risk mitigation. As modern aircraft engines are developed to be lighter, more fuel efficient and cost competitive, their designs may become more susceptible to engine icing risks. To mitigate these risks, icing wind tunnel testing plays a critical role in evaluating engine performance and safety under icing conditions. A successful icing wind tunnel test requires a clear understanding of particle size distribution, particle shape, and particle density. The particles used in testing may include steam-condensed droplets, atomized water spray, and snow or ice crystals.

To develop the capability to characterize icing particle size distribution, particle shape, and particle density, the test setup will incorporate multiple measurement systems. The proposed setup includes a
1) Particle Image Velocimetry (PIV) system to measure particle size, shape, and spatial distribution
2) Wire-resistance-based system to measure particle density
3) Flow-collection device with a particle trap.
Each of these systems can operate independently; however, when used together, they provide a means to calibrate and validate the overall measurement approach. The PIV and wire-resistance measurement data will require software-based post-processing to convert the raw data into meaningful results, including particle size distribution, particle shape, and particle density metrics.