Ice Crystal Environment Modular Axial Compressor Rig: Characterization of Particle Fracture and Melt Across One Rotor Using Laser Shadowgraphy
Jennifer L. Chalmers, Michael Wiebe, Martin Neuteboom, Craig R. Davison
Abstract
The National Research Council of Canada (NRC) has developed the Ice-Crystal Environment Modular Axial Compressor Rig (ICE-MACR) for simulating altitude ice crystal icing of aircraft engines in altitude facilities. Commissioning of the rig under altitude icing conditions was conducted in the NRC’s altitude icing wind tunnel (AIWT) in May-June 2019. The rig consisted a single working compressor stage with a downstream accretion test article representative of a compressor s-duct. Measuring fragmented ice particle size downstream of the working stage is critical to understand the icing conditions at the accretion test article. Particle break-up data across the stage will also be important for validation of numerical icing models. Details of a laser shadowgraph technique used to quantify ice particle size and subsequent results are presented. Results include particle size as a function of rotor speed, and radial distribution of particle size downstream of the rotor. In addition, a process to develop and assess a method of determining the particle melt fraction from the backlit microscopic (shadowgraph) images is presented. The shadowgraph derived melt ratio is compared to Multi-Element probe melt ratio measurement for validation. For the test conditions studied, the melt ratio calculated for the small particle bins (<26 µm) was found to correlate well with the Multi-Element melt ratio. As the shadowgraph data has the ability to quantify the melt ratio of different particle size ranges, it could provide a powerful complement to melt and fracture modeling.