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Type IV Anti-icing Fluid Subjected to Light Freezing Rain: Visual and Thermal Analysis

UQAC - AMIL-Jean-Denis Brassard, Caroline Laforte, Christophe Volat
  • Technical Paper
  • 2019-01-1971
To be published on 2019-06-10 by SAE International in United States
Deicing the aircraft using fluid, prior takeoff is mandatory; since a thin layer of ice or snow can compromise the safety. With the same idea, to use anti-icing fluid during a frozen precipitation to protect the aircraft is also essential. Commercialized anti-icing fluids all pass the process of qualification as described in the SAE documents. One of these documents specifies a set of tests that reproduce freezing precipitation to obtain endurance time and then the holdover timetables. The endurance time is determined by visual inspection: when 30% of the plate is covered with frozen contaminants, the failure is called. With the evolution of technology and the venue of new tools, it may simplify the process, and at least confirm the observations. This paper proposed a thermal and visual analysis of the behaviour of a Type IV fluid subjected to light freezing rain. During the precipitation the plate temperature is recorded using thermocouples and recorded using a visual camera and an IR camera. The results show that the fluids have an interesting thermal behaviour. The use…
 

Simulations of Thin Film Dynamics on a Flat Plate and an Airfoil

Baylor University-Jordan Sakakeeny, Stephen T. McClain, Yue Ling
  • Technical Paper
  • 2019-01-1938
To be published on 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 previous experimental results and numerically 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 numerically 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 solver, Gerris. The Gerris solver employ a finite-volume approach and the interface is…
 

Flight in Icing Regulatory Evolution and the Influence on Aircraft Design

Boeing Co.-David Leopold
  • Technical Paper
  • 2019-01-1958
To be published on 2019-06-10 by SAE International in United States
Flight in icing for transport category aircraft certification presents a particularly challenging set of considerations to establish adequate safety commensurate with the associated risk while balancing design complexity and efficiency. A review highlighting important aspects of the regulatory evolution and guiding principles for flight in icing certification is presented including the current standards and recent rulemaking activity. While historical icing certification relied on a simple yet subjective requirement to demonstrate that an aircraft is capable of operating safely within the prescribed icing envelopes, the certification requirements associated with demonstrating an adequate level of safety have progressively evolved into more explicit quantitative performance and qualitative handling qualities standards now scattered throughout the Federal Aviation Administration (FAA) Title 14 Code of Federal Regulations (CFRs) Part 25 Subpart B Flight standards largely harmonized with other regulatory agencies. Recent rulemaking activity including the introduction of a new icing certification envelope and a potential branching of the regulatory structure to address modern fly-by-wire aircraft not envisioned at the inception of the original flight standards have firmly engrained flight in icing…
 

Influence of Freestream Temperature on Ice Accretion Roughness

Baylor University-Stephen T. McClain
NASA Glenn Research Center-Mario Vargas, Andy Broeren
  • Technical Paper
  • 2019-01-1993
To be published on 2019-06-10 by SAE International in United States
The influence of freestream static temperature on roughness temporal evolution and spatial variation was investigated in the Icing Research Tunnel (IRT) at NASA Glenn Research Center. A 53.34 cm (21-in.) NACA 0012 airfoil model and a 152.4 cm (60-in.) HAARP-II business jet airfoil model were exposed to Appendix C clouds for fixed exposure times and the resulting ice accumulation parameter. For the base conditions, the static temperature was varied to produce different stagnation point freezing fractions. The resulting ice shapes were then scanned using a ROMER Absolute Arm system and analyzed using the self-organizing map approach of McClain and Kreeger. The ice accretion prediction program LEWICE was further used to interrogate the ice accretion point clouds using the predicted surface variations of local collection efficiency. The resulting equivalent sand-grain roughness heights predicted using the correlation of Flack and Schultz are compared to the roughness correlation employed in LEWICE for roughness convection enhancement predictions. The results demonstrate the influence of the stagnation point freezing fraction on the maximum sand-grain roughness height. A new function is developed…
 

A Study of Droplet Breakup in the Vicinity of an Airfoil

INTA-Suthyvann Sor, Adelaida Garcia-Magariño
UPM-Angel Velazquez
  • Technical Paper
  • 2019-01-2000
To be published on 2019-06-10 by SAE International in United States
Supercooled large droplets can breakup before imping on aerodynamic surfaces and this should be taken into account in the icing codes. A study of droplets breakup in the vicinity of an airfoil has been conducted. Experiments for streams of droplets that were allowed to fall in the path of an incoming airfoil attached to a rotatory arm were conducted at the INTA facility. Droplets radius ranged from 500 µm to 1.5 mm and two airfoils models of leading edge radius of 70 mm and 103 mm moving at velocities of 70 m/s, 80 m/s and 90 m/s were tested. Two subsets of experimental data for both bag and stamen breakup and shear breakup modes were used in this investigation. For these cases a numerical trajectory and deformation model was applied to obtain the evolution of the horizontal position, and the droplet maximum and minimum diameter. Breakup onset was determined from experimental data. Though previous works considered that breakup starts when there is a minimum in the minimum diameter, such minimum was not found in the…
 

A Continuing Investigation of Diurnal and Location Trends in an Ice Crystal Icing Engine Event Data Base

Boeing Co-Melissa Bravin
Met Analytics, Inc.-J. Walter Strapp
  • Technical Paper
  • 2019-01-1964
To be published on 2019-06-10 by SAE International in United States
This paper is an update of the analysis of Boeing weather related ICI engine power loss events presented by Bravin et al. (SAE 2015-01-2130). The update will provide summaries of events since 2015, including the geographical and time of day distributions, and an analysis of any overall differences in the meteorological properties during events relative to pre-2015 events. In this paper, continental events in the event data base are studied in more detail. In particular, events over continental landmasses will be individually examined to determine the nature of the clouds in which they occurred. Detailed studies of events over continental Africa and South America will be examined. The intention will be to determine if the frequency of continental events has increased since the earliest studies, to quantify the fraction of cases which can be categorized as vigorous continental convection, to examine when in the evolution of the cloud the event occurred and in what proximity to regions of active cells, and to identify any fundamental differences of engine events in continental versus oceanic clouds. The…
 

Photogrammetric Frost Roughness Measurements in Cold-Soaked Conditions

Baylor University-Taber Miyauchi, Stephen T. McClain, Tongxin Zhang, Dennis L. O'Neal
Federal Aviation Administration (FAA)-James T. Riley
  • Technical Paper
  • 2019-01-1970
To be published on 2019-06-10 by SAE International in United States
Cold-soaked fuel frost (CSFF) is a form of aircraft wing contamination that occurs when a vehicle caries sufficient fuel for multiple trips or take-offs and landings. Following the first trip, which may reach altitudes above 10,000 m (33,000 ft), the fuel for the subsequent trips is carried in the wing tanks and may reach temperatures below -25 C. In certain times of the year at some airports, temperatures and humidity levels will form CSFF on the aircraft wing surfaces over the fuel tanks. Unless an exemption is granted for the aircraft model, aircraft are not allowed to takeoff if the wing surfaces are contaminated by frost. Because aircraft operators desire to minimize vehicle time spent at airports, aircraft manufacturers are expected to pursue designs that safely operate with CSFF at takeoff and to pursue certification exemptions for aircraft models enabling CSFF takeoffs. To assist manufacturers in the design of future aircraft and to assist regulators in evaluating certification exemption requests, more information about frost roughness characteristics and evolution in CSFF conditions is required. However, because…
 

Runway Deicing Product Anti/Deicing Performance Assessment: Review and Future Directions

UQAC - AMIL-Jean-Denis Brassard, Caroline Laforte, Marc Mario Tremblay, Christophe Volat
  • Technical Paper
  • 2019-01-1974
To be published on 2019-06-10 by SAE International in United States
Every winter, northern airport operations are disrupted by heavy snowstorms and freezing precipitations. A simple snow accumulation or a thin layer of ice can affect aircraft operations (take-off, landing and taxi), and increase the risk for passengers and crew members, by rendering the runway slippery. Any defects in deicing operations can also lead to flight delays and even cancellations that cost a lot to the industry. In order to maintain the runway and taxiway safe and practicable, airport authorities use mechanical tools but also chemical products. Chemical products available on the market for use in airports are principally in solid forms and liquid form, and are denominated as Runway Deicing Product (RDP). All of the products used in airport should meet the technical requirements of one of the two Aerospace Materials Specifications (AMS) documents: the AMS1431D Compound, Solid Runway and taxiway Deicing/Anti-icing and the AMS1435C Fluid, Generic, Deicing/Anti-icing Runways and Taxiways. Most of the products are used as freezing point depressants and are apply on snow, ice or packed snow covers to create holes and…
 

Icing Test and Measurement Capabilities of the National Research Council's Gas Turbine Laboratory

National Research Council Canada-Jennifer Chalmers, Craig Davison, James MacLeod, Martin Neuteboom, Dan Fuleki
  • Technical Paper
  • 2019-01-1943
To be published on 2019-06-10 by SAE International in United States
The National Research Council’s Gas Turbine Laboratory provides industry leading icing facilities that allow manufacturers to develop, validate and certify new products for flight in adverse conditions. This paper shows how NRC measurement techniques are used across the facilities, and presents a literature-review of recently developed capabilities. The overview includes new details on some facilities, and future capabilities that are in development or planned for the near future. Methods developed at the NRC for characterizing inclement conditions are discussed and include the Iso-Kinetic Probe, Particle Shadow Velocimetry, the Particle Detection Probe, and a size-binned real-time thermodynamic evaporation model. These are used to deliver accurate icing water content in facilities like the sea-level ice crystal generator, the Rotating Icing Rig, the Research Altitude Testing Facility, and liquid water test facilities in Ottawa and Thompson, Manitoba (Global Aerospace Centre for Icing and Environmental Research - GLACIER).
 

How Dual Polarization Technique May Improve Weather Radar on Commercial Aircraft

NOVIMET-Jacques Victor Testud, Emmanuel Moreau, Erwan Le Bouar
  • Technical Paper
  • 2019-01-1982
To be published on 2019-06-10 by SAE International in United States
The airborne weather radar on a commercial aircraft is essential to ensure flight safety. It is able to detect severe weather, probable areas where presence of hail may be suspected, and thanks to its Doppler capability, the wind shears that may be dangerous when landing. However, because it operates at X-band, the picture that it offers to the pilot may be seriously biased in situation of severe weather, in reason of the attenuation of the radar wave. The adoption of the dual pol technique in this weather radar would be most beneficial for the quality of the information delivered to the pilot for the following reasons: 1- Dual pol technique allows to operate a classification of the precipitation: distinguishing rain, melting layer, snow, hail, small ice particles. 2- Dual pol technique allows correcting the return signal for attenuation in rain. The paper aims to report recent advances in the exploitation of dual pol data, based of the concept of normalisation of the particle size distribution (PSD) and on ZPHI® algorithm for precipitation retrieval. Their combination…