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An experimental study was conducted to characterize the dynamic ice accretion process over the surface of a typical aeronautic Pitot probe model under different icing conditions. The experimental study was conducted in the Icing Research Tunnel available at Iowa State University. While a high-speed imaging system was used to record the dynamic ice accretion process, a three-dimensional (3D) scanning system was also used to measure the 3D shapes of the ice layers accreted on the test model. While opaque and grainy ice structures were found to accrete mainly along the wedge-shaped lip of the front port and over the front surface of the probe holder under a dry rime icing condition, much more complicated ice structures with transparent and glazy appearance were observed to cover almost entire surface of the Pitot probe under a wet glaze icing condition. While a flower-like ice structure was found to grow rapidly along the front port lip, multiple irregular-shaped ice structures accreted over the probe holder under a mixed icing condition. The characteristics of the icing process under different icing conditions were compared in terms of 3D shapes of the ice structures, the profiles of the accreted ice layers, the ice blockage to the front port, and the total ice mass on the Pitot probe model. The acquired ice accretion images were correlated with the 3D ice shape measurements to elucidate the underlying icing physics.
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Experimental Investigation on Ice Accretion Upon Ice Particle Impacting onto Heated Surface
An experimental study was conducted to examine the dynamic ice accretion process upon the impingement of microsized, airborne ice particles/crystals onto a heated test surface pertinent to aeroengine icing phenomena. The experimental study was conducted in a specially designed ice crystal icing test facility to generate and inject microsized ice particles into a frozen-cold airflow. The microsized ice particles were forced to impinge onto a heated test plate with controllable surface temperatures. Upon impingement of the ice particles onto the heated test surface, the dynamic ice accretion process was found to take place over the heated surface in three distinct stages: 1) an ice-melting stage at the beginning, followed by 2) an ice/water mixture formation stage, and then 3) a water refreezing stage, causing the formation of a solid ice layer accreted on the heated test surface eventually. After impinging onto the test plate, while small ice particles with spheric shapes were found to be more ready to bounce off from the test surface, large, nonspheric-shaped ice particles experienced a catastrophic fragmentation process and break up into smaller pieces with noticeable impingement residues remaining on the test surface. The formation of a liquid water film layer on the test surface due to the melting of the impinged ice particles was found to be very beneficial to make more impinged ice particles stay sticking on the test surface, resulting in a rapid growth of the water/ice layer accreted on the heated test surface. A comprehensive theoretical analysis was also performed to examine the unsteady heat transfer characteristics during the dynamic ice accretion process. The theoretic predictions of the collection efficiency of the impinged ice particles on the heated test surface and the temperature variations of the water layer at the initial ice-melting stage were found to agree well with the experimental measurement results.
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- Award ID(s):
- 1916380
- PAR ID:
- 10428917
- Date Published:
- Journal Name:
- AIAA Journal
- Volume:
- 61
- Issue:
- 7
- ISSN:
- 0001-1452
- Page Range / eLocation ID:
- 3019 to 3031
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.2514/1.J062425
