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Technical Paper

Immediate Impacts on Particulate and Gaseous Emissions from a T56 Turbo-Prop Engine Using a Biofuel Blend

2013-09-17
2013-01-2131
Adoption of hydro-processed esters and fatty acid biojet fuels is a critical component for the sustainability of the aviation industry. Aviation biofuels reduce pollution and provide alternatives to conventional fossil fuels. A study of the impacts of biofuels on emissions from a T56 turbo-prop engine was undertaken as a joint effort among several departments of the Government of Canada. In this study, particulate (including particle number and black carbon (BC) mass) and regulated gaseous emissions (CO2, CO, NO, NO2, THC) were characterized with the engine operating on conventional F-34 jet fuel and jet fuel blended with camelina-based hydro-processed biojet fuel (C-HEFA) by 50% in volume. Emissions characterization, conducted after 20-hour ground engine durability tests, showed immediate significant reductions in particle number and BC mass when the engine was operated on the C-HEFA blend.
Technical Paper

Measurement of Liquid Water Content for Supercooled Large Drop Conditions in the NRC’s Altitude Icing Wind Tunnel

2019-06-10
2019-01-2007
As a result of new regulations pertaining to the airworthiness of aircraft exposed to in-flight icing conditions where maximum water drop size is greater than 100 microns (referred to as Supercooled Large Droplet (SLD) conditions), updates are required to the test facilities and simulations that will enable manufactures to certify their products under these new rules. While a number of facilities report achieving some of the conditions specified in the new regulations, questions remain as to the suitability of the instrumentation used to measure the Liquid Water Content (LWC) and drop size distributions of the SLD icing cloud. This study aims to provide baseline LWC data through ice accretion measurement techniques on a NACA 0012 airfoil and rotating cylinders of varying diameters.
Technical Paper

Testing of Elastomer Icephobic Coatings in the AIWT: Lessons Learned

2019-06-10
2019-01-1994
A study has been conducted into icephobic properties of some highly durable “off-the-shelf” elastomer materials using a rotating ice adhesion test rig installed in the NRC’s Altitude Icing Wind Tunnel. This enabled the formation of ice at environmental conditions similar to those experienced during in-flight icing encounters. Initially, the tests indicated some very positive results with ice adhesion shear stress as low as 8KPa. On further examination, however, it became apparent that the test preparation process, in which the samples were cleaned with an ethanol alcohol solution, influenced the results due to absorption and prolonged retention of the cleaning fluid. The uptake of the ethanol alcohol solution by the elastomer was found to be a function of the surface temperature and remained absorbed into the coating during the ice accretion process changing the characteristics of the coating in such a way that led to a reduction in the ice/surface bond strength.
Technical Paper

Four Years of Testing to AS5562

2019-06-10
2019-01-1957
With the publication of SAE AS5562 in 2015, icing wind tunnel test facilities have upgraded their operating environments and instrumentation to meet the client demand to test to this new standard. Nearing four years of testing and development to this standard, numerous questions and challenges have arisen that industry has addressed on an individual basis but not in a common format for all. This paper addresses some of the known challenges in an effort to apply AS5562 consistently across industry and provide clarity to all users.
Technical Paper

Icing Test and Measurement Capabilities of the NRC’s Gas Turbine Laboratory

2019-06-10
2019-01-1943
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 Isokinetic Probe, Particle Shadow Velocimetry, the Particle Detection Probe, and a size-binned real-time thermodynamic evaporation model.
Technical Paper

Validation and Instrumentation of a Small Modular Multi-Stage Axial Compressor for Ice Crystal Icing Research

2019-06-10
2019-01-1940
The National Research Council of Canada (NRC) has undergone the development of a Small Axial Compressor Rig for modelling altitude ice accretion in aircraft engines. The rig consists of two axial compressor stages measuring approximately 150mm in diameter, an extension duct to allow residence time for partial melting of ice crystals and a test piece. The axial compressor stages are intended to provide realistic engine conditioning such as fracture, pressure rise, temperature rise and centrifuging of glaciated ice crystals entering the rig. The rig was designed for use in altitude icing wind tunnels such as the NRC’s altitude icing wind tunnel (AIWT), research altitude test facility (RATFac.), and those of other organization such as NASA Glenn and Technical University of Braunshweig. Previous development work [1] provided partial validation of the aerodynamic performance of just the first compressor stage at 90% power.
Technical Paper

NRC Particle Detection Probe: Results and Analysis from Ground and Flight Tests

2019-06-10
2019-01-1933
High altitude ice crystals are causing in-service events in excess of one per month for commercial aircraft. The effects include air data probes malfunctioning (pitot pressure and total air temperature in particular), and uncommanded engine power loss or flameout events. The National Research Council Canada (NRC) has developed a particle detection probe (PDP) that mounts on the fuselage of aircraft to sense and quantify the ice crystals in the environment. The probe is low-power and non-intrusive. This paper presents the results of ground and flight testing of this probe. Results are presented for ground testing in a sea level ice crystal wind tunnel and an altitude icing tunnel capable of generating both ice crystal and super-cooled liquid. The PDP was operated on several flight campaigns and the results of two will be presented.
Technical Paper

Ice Crystal Icing Test Design and Execution for the ALF502 Vane Segment in the NRC RATFac Cascade Rig

2019-06-10
2019-01-1925
Understanding the behaviour of ice crystal ice (ICI) accretion and shedding inside an aircraft engine is important for safe and reliable engine operation in flight and to meet new airworthiness regulations. A significant advancement in this understanding came from two engine test campaigns carried out on a Honeywell ALF502 turbofan, led by the Ice Crystal Consortium (ICC) and NASA. However, it is often desirable to conduct smaller scale component level tests to both decrease costs and increase the amount of data obtainable, given a component is more accessible when removed from an engine and therefore easier to instrument and observe. That was the purpose of the work discussed in this paper where a segment of an ALF502 low pressure exit guide vane ring was installed in the NRC RATFac ICI cascade rig. The existing cascade rig was modified to accommodate the vane segment which allowed for the instrumentation already available on the rig to be used to characterize the ICI environment.
Technical Paper

Evaluation of Visual Failure versus Aerodynamic Limit for a Snow Contaminated Anti-Iced Wing Section during Simulated Takeoff

2019-06-10
2019-01-1972
Under contract to Airlines for America (A4A), APS Aviation Inc. (APS), in collaboration with the National Research Council of Canada (NRC), completed an aircraft ground icing exploratory research project at the NRC 3 m × 6 m Wind Tunnel in Ottawa in January 2019. The purpose of this project was to investigate the feasibility of using aerodynamic data to evaluate the performance of contaminated anti-icing fluid, rather than the traditional visual fluid failure indicators that are used to develop Holdover Times (HOTs). The aerodynamic performance of a supercritical airfoil model with anti-icing fluids and snow contamination was evaluated against the clean, dry performance of the airfoil in order to calculate the associated aerodynamic penalty. The visual failure of the fluid was also evaluated for each run, and the visual and aerodynamic results were compared against each other for each contamination exposure time.
Technical Paper

Technique for Ice Crystal Particle Size Measurements and Results for the National Research Council of Canada Altitude Ice Crystal Test System

2015-06-15
2015-01-2125
This paper describes the equipment, analysis methods and results obtained for particle size measurements based on a particle imaging velocimetry (PIV) system in which a short duration laser pulse is used to backlight airborne particles. This produces high quality and high resolution images of fast moving airborne particles in a non-intrusive manner. This imaging technique is also used to examine particle morphology and 2D particle trajectory and velocity. The image analysis methods are outlined and validation test results discussed which show the measurement of reference glass beads between 20 and 400 microns were generally to within their stated size. As well, validation testing using known icing wind tunnel droplet distributions were compared with Spraytek 2000 Malvern droplet size measurements and showed agreement of the MVD's to be within ±5% for distributions having nominally 20, 40 and 80 micron MVD's.
Technical Paper

Development and Application of an Impedance-Based Instrument for Measuring the Liquid Fraction and Thickness of Ice Crystal Accretions

2015-06-15
2015-01-2134
Ice crystals ingested by a jet engine at high altitude can partially melt and then accrete within the forward stages of the compressor, potentially causing performance loss, damage and/or flameout. Recent research into this ice crystal icing (ICI) phenomenon conducted at the National Research Council of Canada suggests that the liquid water content vliq of an accretion significantly affects the accretion's susceptibility to erosion by ice crystals, and therefore accretion growth. This paper describes the development and application of an instrument for measuring vliq, potentially providing a method for correlating erosion behavior (e.g. as ductile or brittle) and properties. The instrument measures the complex admittance Y* of a mixed-phase deposit bridging a pair of electrodes, which is modeled as a resistor and capacitor in parallel, and calculates the deposit's relative permittivity εr from the capacitance.
Technical Paper

Progress towards a 3D Numerical Simulation of Ice Accretion on a Swept Wing using the Morphogenetic Approach

2015-06-15
2015-01-2162
We have developed an original, three-dimensional icing modelling capability, called the “morphogenetic” approach, based on a discrete formulation and simulation of ice formation physics. Morphogenetic icing modelling improves on existing ice accretion models, in that it is capable of predicting simultaneous rime and glaze ice accretions and ice accretions with variable density and complex geometries. The objective of this paper is to show preliminary results of simulating complex three-dimensional features such as lobster tails and rime feathers forming on a swept wing. The results are encouraging. They show that the morphogenetic approach can predict realistically both the overall size and detailed structure of the ice accretion forming on a swept wing. Under cold ambient conditions, when drops freeze instantly upon impingement, the numerical ice structure has voids, which reduce its density.
Technical Paper

Ice Accretion Measurements on an Airfoil and Wedge in Mixed-Phase Conditions

2015-06-15
2015-01-2116
This paper presents measurements of ice accretion shape and surface temperature from ice-crystal icing experiments conducted jointly by the National Aeronautics and Space Administration (NASA) and the National Research Council (NRC) of Canada. The data comes from experiments performed at NRC's Research Altitude Test Facility (RATFac) in 2012. The measurements are intended to help develop models of the ice-crystal icing phenomenon associated with engine ice-crystal icing. Ice accretion tests were conducted using two different airfoil models (a NACA 0012 and wedge) at different velocities, temperatures, and pressures although only a limited set of permutations were tested. The wedge airfoil had several tests during which its surface was actively cooled. The ice accretion measurements included leading-edge thickness for both airfoils. The wedge and one case from the NACA 0012 model also included 2D cross-section profile shapes.
Technical Paper

Simulation of Ice Particle Melting in the NRCC RATFac Mixed-Phase Icing Tunnel

2015-06-15
2015-01-2107
Ice crystals ingested by a jet engine at high altitude can partially melt and then accrete within the compressor, potentially causing performance loss, damage and/or flameout. Several studies of this ice crystal icing (ICI) phenomenon conducted in the RATFac (Research Altitude Test Facility) altitude chamber at the National Research Council of Canada (NRCC) have shown that liquid water is required for accretion. CFD-based tools for ICI must therefore be capable of predicting particle melting due to heat transfer from the air warmed by compression and possibly also due to impact with warm surfaces. This paper describes CFD simulations of particle melting and evaporation in the RATFac icing tunnel for the former mechanism, conducted using a Lagrangian particle tracking model combined with a stochastic random walk approach to simulate turbulent dispersion. Inter-phase coupling of heat and mass transfer is achieved with the particle source-in-cell method.
Technical Paper

Development of a Supercooled Large Droplet Environment within the NRC Altitude Icing Wind Tunnel

2015-06-15
2015-01-2092
Simulations of supercooled large droplet (SLD) icing environments within the NRC's Altitude Icing Wind Tunnel (AIWT) have been performed in which broad band mass distribution spectra are achieved that include a distinct pattern of liquid water content (LWC) over a range of droplet sizes (i.e., bi-modal distribution). The mass distribution is achieved through modification of the existing spray system of the AIWT to allow two spray profiles with differing LWC and median volumetric diameter (MVD) to be simultaneously injected into the flow. Results of spray profile distributions measured in the test section have demonstrated that freezing drizzle conditions, where MVD is either less than or greater than 40 μm, can be achieved.
Journal Article

Review of Canadian Flight Deck and Cabin Smoke and Fire Incidents: 2001-2010

2013-09-17
2013-01-2307
This paper presents a review of the flight deck and cabin fire and smoke incidents reported to the Canadian airworthiness authorities over a ten year span. The fire and smoke related diversions are categorized to identify areas where efforts could be increased to improve safety. The costs of diversions are estimated to identify areas where operators could reduce costs by seeking technologies to reduce the number of diversions without any impact on safety. Only twenty-eight investigation reports into fire and smoke incidents onboard aircraft have been published over the past three decades. These reports are not sufficient to identify areas where operators can reduce their operating costs. The Canadian airworthiness authorities received over 1,000 smoke and fire incidents from the years 2001 to 2010, of which, over 680 reported fire and smoke in the flight deck and cabin compartments for various makes and models of aircraft.
Journal Article

Characterization of the Ultrafine and Black Carbon Emissions from Different Aviation Alternative Fuels

2015-09-15
2015-01-2562
This study reports gaseous and particle (ultrafine and black carbon (BC)) emissions from a turbofan engine core on standard Jet A-1 and three alternative fuels, including 100% hydrothermolysis synthetic kerosene with aromatics (CH-SKA), 50% Hydro-processed Esters and Fatty Acid paraffinic kerosene (HEFA-SPK), and 100% Fischer Tropsch (FT-SPK). Gaseous emissions from this engine for various fuels were similar but significant differences in particle emissions were observed. During the idle condition, it was observed that the non-refractory mass fraction in the emitted particles were higher than during higher engine load condition. This observation is consistent for all test fuels. The 100% CH-SKA fuel was found to have noticeable reductions in BC emissions when compared to Jet A-1 by 28-38% by different BC instruments (and 7% in refractory particle number (PN) emissions) at take-off condition.
Technical Paper

Gaseous and Particle Emissions from a Turbo-Jet Engine Operating on Alternative Fuels at Simulated Altitudes

2011-10-18
2011-01-2597
Gaseous and particle emission assessments on a 1.15 kN-thrust turbojet engine were conducted at five altitudes in an altitude chamber with Jet A-1 fuel, pure Fischer Tropsch (FT), and two mixed fuels of JP-8 with FT or Camelina-based hydro-processed jet fuels. In general, lower emissions in CO₂, NOx, and particle number as well as higher emissions in CO and THC were observed at higher altitudes compared to lower altitudes. These observations, which were similar for all test fuels, were attributed to the reduced combustion efficiency and temperature at higher altitudes. The use of alternative fuels resulted in lower CO₂ emissions, ranging from 0.7% to 1.7% for 50% to 100% synthetic fuel in the fuel mixture at various altitudes. In terms of CO, the use of 100% FT fuel resulted in CO reduction up to 9.7% at 1525 m altitude and up to 5.9% at 9145 m altitude.
Technical Paper

Aircraft Performance Degradation - the Effects of Inflight Icing upon Lift, Drag and Propulsive Efficiency

2011-06-13
2011-38-0073
Data is presented from a number of flight research aircraft, which have been involved in the research of the effects of inflight icing, in a variety of atmospheric supercooled droplet and mixed-phase icing environmental conditions. The aircraft Types considered cover both Pneumatic and Thermal Ice Protection Systems (IPS). Icing includes supercooled droplet impact icing upon airframe and propeller blades and cold-soaked frost icing. The drag effects of inflight icing, from mixed-phase small and large droplets encountered during the course of SALPEX cloud physics research operations, upon a Fokker F-27 turboprop transport aircraft, have been analyzed. Furthermore, during the course of AIRS 1.5 and AIRS II inflight icing flight research operations, the NRC Convair conducted aerodynamic characterization maneuvers, following and during icing accretion in a wide range of environmental conditions of altitude, air temperature, LWC and droplet spectra.
Technical Paper

Development and Commissioning of a Linear Compressor Cascade Rig for Ice Crystal Research

2011-06-13
2011-38-0079
This paper describes the commissioning of a linear compressor cascade rig for ice crystal research. The rig is located in an altitude chamber so the test section stagnation pressure, temperature and Mach number can be varied independently. The facility is open-circuit which eliminates the possibility of recirculating ice crystals reentering the test section and modifying the median mass diameter and total water content in time. As this is an innovative facility, the operating procedures and instrumentation used are discussed. Sample flow quality data are presented showing the distribution of velocity, temperature, turbulence intensity and ice water concentration in the test section. The control and repeatability of experimental parameters is also discussed.
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