Convection from ice roughness surfaces using scaled Reynolds numbers for larger NACA 0012 airfoils.

Ice accretions that develop on aircraft surfaces during flight adversely impact performance by increasing weight and drag, while also decreasing lift and stall margin. Previous studies at Baylor University characterized the convective heat transfer for roughness surfaces exposed to accelerating flow similar to that experienced by a 21-in. NACA 0012 airfoil. The current study characterizes the convective heat transfer using the same roughness surfaces but exposed to flow scaled to that of a larger NACA 0012 airfoil by increasing wind tunnel velocity and thus scaling the Reynolds number. This scaling is appropriate based on previous studies performed in the Icing Research Tunnel (IRT) at the NASA Glenn Research Center that determined relative roughness in the collection region of a 21-in. and a 72-in. NACA 0012 airfoil, with similar collection efficiencies, scales geometrically with airfoil chord. The convective heat transfer coefficients on rough surfaces under scaled Reynolds number conditions were measured.