Wind Tunnel Measurements of Simulated Glaciated Cloud Conditions to Evaluate Newly Developed 2D Imaging Probes 2019-01-1981
The instrumentation that has been used for characterization of mixed-phase and glaciated conditions in the past is not considered to be adequate for the high ice water content (IWC) environments judged to represent a significant safety hazard to propellers and turbofan engine operability and performance. For this reason, within the frame of EU FP7 HAIC project, the instrumentation was considered a major key element for successful execution of flight tests campaigns. This is true also because the instrumentation has to assess the reproducibility of clouds with high ice water content in icing tunnels, where is requested to measure the conditions with a sufficient level of accuracy for the purposes of the testing. There is a basic uncertainty of a factor of 2-5 may be worse for thunderstorm core regions, because of the importance of the poorly measured ice particle sizes below 100 μm with current instruments. Measurements below 100 μm are especially difficult for ice particles. In order to limit this measurement issue, an innovative approach for imaging droplets and ice crystals was considered in this work. This method is based on Artium Technologies Inc. High Speed Imaging (HSI) and utilizes a unique multi-beam illumination approach to control the depth of field and to minimize noise effects due to out-of-focus small particles. Rather than utilizing a linear array to acquire the images, a CMOS two-dimensional array imaging system is used. The lasers used for producing bright field shadow images are pulsed synchronously and have pulse duration of as little as 12.5 ns to “freeze” the particle motion. The response of the HSI will be reviewed on the basis of comparison with SPEC 2D-S by means of wind tunnel measurements for glaciated cloud conditions.
Biagio M. Esposito, William D. Bachalo, Delphine Leroy, Alfons Schwarzenboeck, Tina Jurkat, Christiane Voigt, Stephan Bansmer
CIRA, Italian Aerospace Research Centre, Artium Technologies Inc, CNRS, LaMP, Laboratoire de Météorologie Physiq, DLR, German Aerospace Center, Technische Universität Braunschweig
International Conference on Icing of Aircraft, Engines, and Structures