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Rime ice accretion and its effect on airfoil performanceA methodology was developed to predict the growth of rime ice, and the resulting aerodynamic penalty on unprotected, subcritical, airfoil surfaces. The system of equations governing the trajectory of a water droplet in the airfoil flowfield is developed and a numerical solution is obtained to predict the mass flux of super cooled water droplets freezing on impact. A rime ice shape is predicted. The effect of time on the ice growth is modeled by a time-stepping procedure where the flowfield and droplet mass flux are updated periodically through the ice accretion process. Two similarity parameters, the trajectory similarity parameter and accumulation parameter, are found to govern the accretion of rime ice. In addition, an analytical solution is presented for Langmuir's classical modified inertia parameter. The aerodynamic evaluation of the effect of the ice accretion on airfoil performance is determined using an existing airfoil analysis code with empirical corrections. The change in maximum lift coefficient is found from an analysis of the new iced airfoil shape. The drag correction needed due to the severe surface roughness is formulated from existing iced airfoil and rough airfoil data. A small scale wind tunnel test was conducted to determine the change in airfoil performance due to a simulated rime ice shape.
Document ID
19820016290
Document Type
Thesis/Dissertation
Authors
Bragg, M. B.
(Ohio State Univ. Columbus, OH, United States)
Date Acquired
September 4, 2013
Publication Date
March 1, 1982
Subject Category
Aerodynamics
Report/Patent Number
NASA-CR-165599
NAS 1.26:165599
Accession Number
82N24166
Funding Number(s)
PROJECT: RTOP 505-44-12
CONTRACT_GRANT: NAG3-28
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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