Evaluation of the Water Film Weber Number in Glaze Icing Scaling

Icing scaling tests were performed in the NASA Glenn Icing Research Tunnel to evaluate a new scaling method (Ref. 1), developed and proposed by Feo for glaze icing, in which the scale liquid water content and velocity were found by matching reference and scale values of the nondimensional water-film thickness expression and the film Weber number. For comparison purpose, tests were also conducted using the constant We L method for velocity scaling. The reference tests used a full-span, fiberglass, 91.4-cm-chord NACA 0012 model with velocities of 76 and 100 knot and MVD sizes of 150 and 195 m. Scale-to-reference model size ratio was 1:2.6. All tests were made at 0° AOA. Results will be presented for stagnation point freezing fractions of 0.3 and 0.5. Introduction The ability to conduct icing tests with subscale aircraft components in an icing wind tunnel depends critically on our understanding of physical mechanisms that affect the ice accretion process and our ability to measure and control test conditions in an icing tunnel. The need to develop appropriate scaling methods has been long recognized, and research efforts have begun as early as in the 1950s and continue to the present. Recently, Anderson (Ref. 2) and Anderson and Tsao (Ref. 3) have completed two NASA reports that provide a detailed technical review of recommended scaling methods for ice accretion on unprotected, unswept aerodynamic surfaces in Appendix C and super-cooled large droplets (i.e., SLD) conditions, respectively. It was concluded from those two references that acceptable scaling results could be achieved by matching the