Super-cooled large droplet ice accretion reproduction and scaling law validation

Edward T. Rocco, Yiqiang Han, Jose Palacios, Richard Kreeger

Research output: Chapter in Book/Report/Conference proceedingConference contribution

7 Scopus citations


The simulation of icing conditions is sought for potential aircraft certification, and therefore test facilities that can generate conditions able to reproduce the ice accretion phenomena are necessary. The icing conditions that aircraft endure are outlined in FAA regulations – namely, FAR 14 Part 25 Appendix C and Part 33 Appendix O. Multiple icing facilities exist for FAR 14 Part 25 Appendix C conditions, however developing facilities that can replicate Super-cooled large droplet (SLD) related to Appendix O is difficult due to the shortcomings of horizontal wind tunnels when generating SLD particles. This research attempts to reproduce SLD icing conditions in the Adverse Environment Rotor Test Stand (AERTS) at Penn State University. The facility is formed by icing nozzles located above a rotor. The vertical spray configuration avoids gravitational effects that can bias large droplets towards the lower portion of a test section in a conventional icing wind tunnel. Data from three (3) test conditions conducted suggests that the AERTS facility can adequately produce SLD conditions. Research is on-going to further validate the AERTS cloud reproduction capability. Ice shape modeling software such as LEWICE currently exhibit uncertainty in the SLD regime. LEWICE, with and without an improved heat transfer model developed in prior research were compared to the three (3) test cases. Results suggest that the AERTS facility produces representative SLD shapes, and that the prediction models are valuable in the SLD regime, especially when using improved heat transfer models. The improved prediction consistently better predicted stagnation thickness (26.02±5.03% improvement) and horn formation when compared to legacy LEWICE heat transfer models. The ice shape scaling laws for SLD conditions were also investigated. Standard scaling laws applicable to Appendix C icing conditions were implemented to SLD regimes. These laws have been tested at NASA Glenn Icing Research Tunnel for SLD, but investigation of the scaling laws in other test facilities was requested to further validate the results. The results of this research, comparing three (3) scaling tests with the three (3) SLD tests previously mentioned, suggest that the ice scaling laws apply in the SLD regime as previously discussed in the literature.

Original languageEnglish (US)
Title of host publication8th AIAA Atmospheric and Space Environments Conference
PublisherAmerican Institute of Aeronautics and Astronautics Inc, AIAA
ISBN (Print)9781624104336
StatePublished - 2016
Event8th AIAA Atmospheric and Space Environments Conference, 2016 - Washington, United States
Duration: Jun 13 2016Jun 17 2016

Publication series

Name8th AIAA Atmospheric and Space Environments Conference


Other8th AIAA Atmospheric and Space Environments Conference, 2016
Country/TerritoryUnited States

All Science Journal Classification (ASJC) codes

  • Space and Planetary Science
  • Atmospheric Science


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