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A Three-Layer Thermodynamic Model for Ice Crystal Accretion on Warm Surfaces: EMM-C

Rolls-Royce Plc-Geoffrey Jones, Benjamin Collier
University of Oxford-Alexander Bucknell, Matthew McGilvray, David Gillespie
Published 2019-06-10 by SAE International in United States
Ingestion of high altitude atmospheric ice particles can be hazardous to gas turbine engines in flight. Ice accretion may occur in the core compression system, leading to blockage of the core gas path, blade damage and/or flameout. Numerous engine powerloss events since 1990 have been attributed to this mechanism. An expansion in engine certification requirements to incorporate ice crystal conditions has spurred efforts to develop analytical models for phenomenon, as a method of demonstrating safe operation. A necessary component of a complete analytical icing model is a thermodynamic accretion model. Continuity and energy balances are performed using the local flow conditions and the mass fluxes of ice and water that are incident on a surface to predict the accretion growth rate. In this paper, a new thermodynamic model for ice crystal accretion is developed through adaptation of the Extended Messinger Model (EMM) from supercooled water conditions to mixed phase conditions (ice crystal and supercooled water). A novel three-layer accretion structure is proposed and the underlying equations described. The EMM improves upon the original model for…
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Simulations of Thin Film Dynamics on a Flat Plate and an Airfoil

Baylor University-Jordan Sakakeeny, Stephen T. McClain, Yue Ling
Published 2019-06-10 by SAE International in United States
The goal of the present study is to investigate the dynamics of a thin water film on a flat plate and an airfoil using direct numerical simulation (DNS). The first case for a wetted flat plate is used to model former experiments and investigate the dynamics of a wind-driven water film. The second case for a thin film on a NACA 0012 airfoil of chord length 0.5 m is used to investigate the dynamics of a wind-driven water film on a curved surface. Particular attention is paid to the interaction between the liquid film and the air shear-layer above the film. As the incoming airflow moves over the thin water film, instability is triggered at the gas-liquid interface. Interfacial waves develop and are advected downstream. The interaction between the air flow and the interfacial waves induces shedding vortices near the interface, which in turn perturb the liquid film farther downstream. Simulations are performed using the open source multiphase flow solvers, Gerris and Basilisk. Both solvers employ a finite-volume approach and the interface is captured using…
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Separating-Reattaching Flows Over an Iced Airfoil

Diakon Solutions LLC-Ezgi Oztekin
Federal Aviation Administration (FAA)-James Riley
Published 2019-06-10 by SAE International in United States
Delayed Detached Eddy Simulations (DDES) of separating-reattaching flows on the suction side of an ice-contaminated airfoil were conducted. A single-section straight-wing NACA23012 airfoil with leading-edge ice was studied. The geometry represents a realistic glaze horn-ice contamination obtained during the icing test campaigns described in [1], which has aerodynamic data for comparison. The three-dimensional transient flow behavior was simulated using the open-source flow solver OVERFLOW, version 2.2l [2] developed by NASA Langley Research Center. Configurations at three angles of attack that exhibit unsteady flow behavior starting with the bursting angle were examined at Mach number of 0.18 and Reynolds number of 1.8x106. As the stall angle was approached the aerodynamic performance parameters displayed large-scale unsteadiness where periods of attached and separated flows were observed. The time-averaged results show good agreement with the aerodynamic test data. The calculated Strouhal number for the self-sustained low-frequency oscillations is consistent with the previous experimental research.
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Numerical Simulation of Aircraft and Variable-Pitch Propeller Icing with Explicit Coupling

ANSYS Inc.-Isik Ozcer, Guido S. Baruzzi, Miraj Desai, Maged Yassin
Published 2019-06-10 by SAE International in United States
A 3D CFD methodology is presented to simulate ice build-up on propeller blades exposed to known icing conditions in flight, with automatic blade pitch variation at constant RPM to maintain the desired thrust. One blade of a six-blade propeller and a 70-passenger twin-engine turboprop are analyzed as stand-alone components in a multi-shot quasi-steady icing simulation. The thrust that must be generated by the propellers is obtained from the drag computed on the aircraft. The flight conditions are typical for a 70-passenger twin-engine turboprop in a holding pattern in Appendix C icing conditions: 190 kts at an altitude of 6,000 ft. The rotation rate remains constant at 850 rpm, a typical operating condition for this flight envelope. Two icing conditions are simulated: air static temperature -23 °C, LWC 0.2 g/m3 and MVD 20 microns resulting in rime ice, and air static temperature -16 °C, LWC 0.3 g/m3 and MVD 20 microns resulting in mixed ice with rime to glaze transition in the radial direction. The ice shapes in both conditions are assumed to remain intact and…
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A Penalization Method for 2D Ice Accretion Simulations

Ecole Polytechnique Montreal-Pierre Lavoie, Eric Laurendeau
ONERA-Ghislain Blanchard, Emmanuel Radenac, Philippe Villedieu
Published 2019-06-10 by SAE International in United States
Numerical tools for 3D in-flight icing simulations are not straightforward to automate when seeking robustness and quality of the results. Difficulties arise from the geometry and mesh updates which need to be treated with care to avoid folding of the geometry, negative volumes or poor mesh quality. This paper aims at solving the mesh update issue by avoiding the re-meshing of the iced geometry. An immersed boundary method (here, penalization) is applied to a 2D ice accretion suite for multi-step icing simulations. The suggested approach starts from a standard body-fitted mesh, thus keeping the same solution for the first icing layer. Then, instead of updating the mesh, a penalization method is applied including: the detection of the immersed boundary, the penalization of the volume solvers to impose the boundary condition and the extraction of the surface data from the field solution. Although the current work is intended for 3D simulations, the content of this paper is limited to 2D applications to show the feasibility of the method. Tests are performed on multi-step rime and glaze…
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As automotive climates shift, GKN ramps up its winter testing

Automotive Engineering: June 2019

Paul Seredynski
  • Magazine Article
  • 19AUTP06_13
Published 2019-06-01 by SAE International in United States

As the influx of electrification continues to roil the industry, seamlessly integrating the hardware and wealth of software it brings with it creates a far broader engineering challenge. Tier-1 companies that traditionally supplied “parts” are rapidly transitioning from a component-level mindset to system-level projects that include exponential investments in programming and control algorithms. Meshing innovative electrified propulsion systems while still meeting diverse and performance-hungry OEM integration criteria is making winter testing more crucial than ever.

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Standard for Safety Glazing Materials for Glazing Motor Vehicles and Motor Vehicle Equipment Operating on Land Highways - Safety Standard

Glazing Materials Standards Committee
  • Ground Vehicle Standard
  • J3097Z26_201905
  • Current
Published 2019-05-28 by SAE International in United States

Specifications, test methods, and usage provisions for safety glazing materials used for glazing of motor vehicles and motor vehicle equipment operating on land highways.

 

Coating Prevents Fogging on Transparent Surfaces

  • Magazine Article
  • TBMG-34409
Published 2019-05-01 by Tech Briefs Media Group in United States

Anyone who skis, wears glasses, uses a camera, or drives a car is familiar with the problem: Coming into a humid environment from the cold causes eyewear, camera lenses, or windshields to quickly fog up. Researchers have developed a new transparent material coating that greatly reduces this effect. A few nanometers thick, the durable coating is made of gold nanoparticles embedded in non-conductive titanium oxide.

 

Test Procedure for Determining the Resistance of Safety-Glazing Materials, of which One Surface is Plastic, to Simulated Weathering

Glazing Materials Standards Committee
  • Ground Vehicle Standard
  • J2081_201904
  • Current
Published 2019-04-11 by SAE International in United States
This SAE Recommended Practice determines whether plastic and glass-plastic safety glazing materials will successfully withstand exposure to simulated weathering conditions.
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Plastic Motor Vehicle Safety Glazing - Tolerances and Fabrication Details

Glazing Materials Standards Committee
  • Ground Vehicle Standard
  • J1691_201904
  • Current
Published 2019-04-11 by SAE International in United States
This SAE Recommended Practice is intended to cover plastic safety glazing for use in motor vehicles and motor vehicle equipment. Nominal specifications for thickness, flatness, curvature, size, and fabrication details are presented principally for the guidance of body engineers and designers. For additional information on plastic safety glazing materials for use in motor vehicles and motor vehicle equipment, please refer to SAE J673.
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