Analysis of Experimental Ice Accretion Data and Assessment of a Thermodynamic Model During Ice Crystal Icing 2019-01-2016
This paper evaluates a thermodynamic ice crystal icing model that has been previously presented to describe the possible mechanisms of icing within the core of a turbofan jet engine. The model functions between two distinct ice accretions based on a surface energy balance: freeze-dominated icing and melt-dominated icing. Freeze-dominated icing occurs when liquid water freezes and accretes on a surface along with the existing ice of the impinging water and ice mass. Melt-dominated icing occurs as unmelted ice on a surface accumulates. Experimentally observed ice growth rates suggest that only a small fraction of the impinging ice remains on the surface, implying a mass loss mechanism such as splash, runback, bounce, or erosion. This mass loss parameter, however, along with the freeze fraction (related to freeze-dominated) and melt fraction (related to melt-dominated icing) are the only experimental parameters that are currently not measured directly. Using icing growth rates from ice crystal icing experiments, a methodology that has been previously proposed is used to determine these unknown parameters. This work takes ice accretion data from tests conducted by the National Aeronautics and Space Administration (NASA) at the Glenn Research Center in 2018 that examined the fundamental physics of ice crystal icing. Those research efforts sought to generate icing conditions representative of those that occur inside a jet engine when ingesting ice crystals, and were conducted in the Propulsion Systems Laboratory. This paper continues evaluation of the thermodynamic model from a previous effort.
Tadas P. Bartkus, Jen-Ching Tsao, Peter M. Struk
Ohio Aerospace Institute, NASA Glenn Research Center
International Conference on Icing of Aircraft, Engines, and Structures