19910001553 · Progress Toward the Development of an Airfoil Icing Analysis Capability

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Z L %.__ ¢._ Profess Toward the Development of an Airfoil Icing Analysis Capability M.G. Potapczek C.S. Bidtoeli NASA Lewis Research Center, Cleveland, Ohio B.M. Berkowitz 5verdrup Technology, Inc., Middleburg Hrs., Ohio The NASA-Lewis aircraft icing analysis program is composed of three major sub-programs.

These sub-programs are ice accretion simulation, performance degradation evaluation, and ice protection system evaluation. These topics cover all area of concern related to the simulation of aircraft icing and its consequences. The motivation for these activities is twofold, reduction of time and effort required in experimental programs and the ability to provide reliable information for aircraft certification in icing, over the complete range of environmental conditions. In addition to the analytical activities associated with development of these codes, several experimental programs are underway to provide verification information for existing codes. These experimental programs are also used to investigate the physical processes associated with ice accretion and removal for improvement of present analytical models. The NASA-Lewis icing analysis program is thus striving to provide a full . • r range of analytical tools necessary for evaluation of the consequences of icing and of ice protection systems.

Recently, two of these tools were used to produce a computational evaluation of the ice accretion process and resulting performance changes for a NACA0012 airfoil. The ice accretion code, LEWICE, provided the ice shape geometry at several points in time during the simulated icing encounter. The predicted shapes are a function of several environmental input parameters, including airspeed, temperature, water droplet size and distribution, liquid water content, and duration of the encounter.

These ice shape geometries are then used as input for a Navier-Stokes analysis code, ARC2D, which calculates the flowfield and determines changes in performance characteristics of the airfoil. Presently, there is no direct link between the two codes and all interfacing is done by the user. One of the objectives of the icing analysis program is to combine codes such as these into a comprehensive icing analysis method. Work in this area is currently underway via a number of grant supported activities.

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