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Title Large-scale swept-wing ice accretion modeling in the NASA Glenn Icing Research Tunnel using LEWICE3D
Publication Date
Date Accessioned
Degree MS
Discipline/Department 4048
Degree Level thesis
University/Publisher University of Illinois – Urbana-Champaign
Abstract The study of aircraft icing is necessary to ensure the safety of commercial, military, and general aviation aircraft. The certification of modern commercial transports requires manufacturers to demonstrate that these aircraft can safely operate during icing conditions consistent with the standards set forth by the Federal Aviation Administration (FAA). While some of these tests are performed on actual aircraft in flight, this is often very expensive and does not provide an adequately controlled matrix of test conditions. Computational tools are used throughout the design and certification of anti-ice systems. However, computational methods alone are not sufficient for aircraft certification. Icing wind tunnels are used for aircraft certification to reduce costs, provide a controlled test matrix of conditions, and validate computational icing tools. The size of aircraft models that can be tested in icing wind tunnels is limited by the size and capability of existing facilities. Large wings, such as those found on modern narrow and wide-body commercial transports, cannot fit in existing test sections without being dramatically scaled. Two methods of scaling exist. The first involves geometrically scaling a section of the reference wing to fit inside the tunnel test section and then scaling the icing conditions in order to maintain icing similitude. The second method maintains the full-scale leading edge of the reference geometry but replaces the aft section of the wing with a tail that is designed to produce similar flow around the leading edge but with a considerably shorter chord length, reducing model size and blockage. This type of model is called a hybrid and is used to generate full-scale ice shapes so that, in the simplest cases, no icing scaling is necessary. However, the methods can be combined so that the hybrid model design is used to maintain geometric similitude while icing scaling is employed to account for differences in pressure, velocity, or other conditions. Modern commercial transport aircraft have large, swept wings. While a broad set of experimental data exist in the literature for airfoil and straight wing icing, there is a distinct lack of data for large, swept wings. Such data is needed in order to better understand the 3D icing physics on swept wings and to allow computational tools to be developed and validated for 3D ice features such as scallops. In this thesis, computational tools were used to better understand the flow over a large-scale, swept-wing, hybrid model mounted vertically in the NASA Glenn Icing Research Tunnel (IRT). Fluent, a commercial CFD code, was used to calculate flows around the flapped-hybrid model in the IRT, mounted with the root at the floor and the tip at the ceiling of the test section. Inviscid analysis reveals that the upwash ahead of the model causes the local lift coefficient to increase significantly across the swept model due to the effect of the floor and ceiling. This change in spanwise loading is shown to move the attachment line location farther…
Subjects/Keywords aircraft icing; icing; ice shape; Accretion; sweep; swept; wing; computational fluid dynamics (CFD); aircraft certification; hybrid; similitude
Contributors Bragg, Michael B. (advisor)
Language en
Rights Copyright 2013 Brock Wiberg
Country of Publication us
Record ID handle:2142/46609
Repository uiuc
Date Indexed 2020-03-09
Grantor University of Illinois at Urbana-Champaign
Issued Date 2014-01-16 17:56:05

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…chord sweep of 35 deg. The supercritical wing was designed for a cruise Mach number of M = 0.85. The aircraft body extends to 10% semispan with a yehudi break at 37% semispan and 8 deg. of washout from side-of-body to tip. The full configuration includes…

…fuselage similar to a modern wide-body aircraft with a transonic wing having a quarter-chord sweep of Λ = 35 deg. (see Table 1.1). The supercritical wing was designed for a cruise Mach number of M = 0.85 and lift coefficient of CL = 0.50 at a…

…Simple Sweep Theory . . . . . . . . . . . . . . . . 2.2.3 Wing Model Design . . . . . . . . . . . . . . . . . 2.3 3D Meshing and Flow Solutions . . . . . . . . . . . . . . . 2.3.1 IRT Mesh Topology . . . . . . . . . . . . . . . . . 2.3.2 Anisotropic…

…position to wing semispan, b/2 θ = ice horn angle Λ = wing sweep angle λ = wing taper ratio µ = dynamic viscosity ν = kinematic viscosity ρ = freestream air density τ = icing exposure time ω = specific turbulence dissipation rate Subscripts…

…Factor SST = Shear Stress Transport TWE = Total Water Exposure xiv UIUC = University of Illinois at Urbana-Champaign WB = Wing-Body xv Chapter 1 Introduction 1.1 Motivation The study of aircraft icing is critical to the safe operation of…

…understanding. 1.3 Large-Scale Swept-Wing Ice Accretion Project In order to better understand aircraft icing on large-scale, swept wings, NASA, the FAA, The French Aerospace Lab (ONERA), the University of Illinois at Urbana-Champaign (UIUC)…

…a swept-wing configuration that is representative of a modern transport aircraft was needed as a baseline for this project. Additionally, the model could not be proprietary or export controlled so that the work performed could benefit all parties…

…more effectively by both academics and aircraft manufacturers. The CRM was designed by Boeing as part of a collaboration with NASA [15]. The CRM features a fuselage similar to a modern wide-body aircraft with a transonic wing having a quarter…