Browse Topic: Icing and ice detection

Items (847)
This SAE Aerospace Recommended Practice (ARP) provides recommended practices for the calibration and acceptance of icing wind tunnels to be used in testing of aircraft components and systems and for the development of simulated ice shapes. This document is not directly applicable to air-breathing propulsion test facilities configured for the purposes of engine icing tests, which are covered in AIR6189. This document also does not provide recommended practices for creating Supercooled Large Drop (SLD) or ice crystal conditions, since information on these conditions is not sufficiently mature for a recommended practice document at the time of publication of ARP5905A. Use of facilities as part of an aircraft’s ice protection Certification Plan should be reviewed and accepted by the applicable regulatory agency prior to testing. Following acceptance of a test plan, data generated in these facilities may be submitted to regulatory agencies for use in the certification of aircraft ice
AC-9C Aircraft Icing Technology Committee
Crawler Dozers play a critical role in global construction, mining and industrial sectors, performing essential tasks like pushing the material, grading, leveling and scraping. In the highly competitive dozer market, meeting the growing demand for increased productivity requires strategies to enhance blade capacity and width. Dozer operations involve pushing the material and dozing, where blade capacity significantly influences performance. Factors such as mold board profile, blade height, and width impact the blade capacity which are crucial for productivity in light weight applications such as snow removal and dirt pushing. Blade width is also pivotal for grading and leveling tasks. Traditional blade designs, like straight or fixed U-type blades, constrain operator flexibility, limiting overall productivity. The integration of hydraulic-operated foldable wings on both sides of the blade offers the adaptability to adjust blade capacity which also helps to reduce material spillage
Sahoo, Jyoti PrakashSarma, Neelam Kumar
This SAE Aerospace Standard (AS)/Minimum Operational Performance Specification (MOPS) specifies the minimum performance requirements of remote on-ground ice detection systems (ROGIDS). These systems are ground based. They provide information that indicates whether frozen contamination is present on aircraft surfaces. Section 1 provides information required to understand the need for the ROGIDS, ROGIDS characteristics, and tests that are defined in subsequent sections. It describes typical ROGIDS applications and operational objectives and is the basis for the performance criteria stated in Sections 3 through 5. Section 2 provides reference information, including related documents, definitions, and abbreviations. Section 3 contains general design requirements for the ROGIDS. Section 4 contains the Minimum Operational Performance Requirements for the ROGIDS, which define performance in icing conditions likely to be encountered during ground operations. Section 5 describes environmental
G-12HOT Holdover Time Committee
Ice build-up on aircraft and wind turbines can impact the safety and efficiency of their systems.
Protecting against atmospheric icing conditions is critical for the safety of aircraft during flight. Sensors and probes are often used to indicate the presence of icing conditions, enabling the aircraft to engage their ice protection systems and exit the icing cloud. Supercooled large drop icing conditions, which are defined in Appendix O of 14 CFR Part 25, pose additional aircraft certification challenges and requirements as compared to conventional icing conditions, which are defined in Appendix C of 14 CFR Part 25. For this reason, developing sensors that can not only indicate the presence of ice, but can also differentiate between Appendix O and Appendix C icing conditions, is of particular interest to the aviation industry and to federal agencies. Developing detectors capable of meeting this challenge is the focus of SENS4ICE, a European Union sponsored project. While participating in the SENS4ICE Project, Collins Aerospace has developed an ice detection and differentiation
Hamman, MatthewGelao, GiancarloRidouane, El HassanChabukswar, RohanBotura, Galdemir
Ice prediction capabilities for Unmanned Aerial Systems (UAS) is of growing interest as UAS designs and applications become more diverse. This report summarizes the current state-of-the-art in modeling aircraft icing within a computational framework as well as a recent U.S. Army DEVCOM AvMC effort to evaluate ice prediction models for current use and future integration into the Computational Research and Engineering Acquisition Tools and Environments (CREATE) Air Vehicle (AV) framework. U.S. Army Combat Capabilities Development Command, Redstone Arsenal, Alabama Historically, smaller Unmanned Aerial Systems (UAS), such as Class 2 RQ-1B Raven and Class 3 RQ-7Bv2 Shadow, have been restricted to not be approved to fly in icing conditions under the assumption that any ice accretion would cause an unacceptable risk of loss of the aircraft. However, interest exists in better understanding potential icing accretion on UAS to determine if less extreme icing conditions could result in only
Historically, smaller Unmanned Aerial Systems (UAS), such as Class 2 RQ-1B Raven and Class 3 RQ-7Bv2 Shadow, have been restricted to not be approved to fly in icing conditions under the assumption that any ice accretion would cause an unacceptable risk of loss of the aircraft. However, interest exists in better understanding potential icing accretion on UAS to determine if less extreme icing conditions could result in only partial degradation and not total loss of the vehicle for the purpose of expanding approved flight envelopes. Icing accretion can be tested during a flight test, which is considered unacceptable due to lack of controlled conditions and risk to the UAS or in a controlled experiment, by using wind tunnel testing to evaluate a single icing condition. Cryogenic wind tunnel tests, such as those conducted at the National Aeronautical and Space Administration (NASA) Glenn Icing Research Tunnel (IRT), Cleveland, OH, as shown in figures 1 and 2, are prohibitively expensive
Brake squeal is a common phenomenon across all types of vehicles. It becomes prominent in the absence of other noise sources, as in the case of electric vehicles. Earlier simulation attempts date back to late nineties and early 2000s. Identification of unstable modes of the coupled system of brake rotor and pads, and occasionally some caliper components, was the primary goal. Simulating the rotation of the rotor along with squeezing of the pads was attempted in a multi-body dynamics tools with flexible representation of rotor and pads. Though this gave some insights into the dynamics of stopping mechanism, squeal required capturing the nonlinearities of the contact in a more rigorous sense. Also, efforts were made to capture noise from vibrations using boundary- and finite- element methods [1]. In this attempt at digitalizing a brake dynamometer, the author used a nonlinear implicit solver to mimic the dynamics and transient vibro-acoustic solver to convert transient vibrations to
Kappagantu, Ramana
The European Union’s Horizon 2020 programme has funded the SENS4ICE (Sensors for Certifiable Hybrid Architectures for Safer Aviation in Icing Environment) project [1], an innovative approach for the development and testing of new sensors for the detection of supercooled large droplets (SLD). SLD may impinge behind the protected surfaces of aircraft and therefore represents a threat to aviation safety. The newly developed sensors will be tested in combination with an indirect detection method on two aircraft, in two parallel flight programs: One on the Embraer Phenom 300 in the U.S. and one on the ATR-42 in Europe. In this framework the Deutsches Zentrum für Luft- und Raumfahrt (German Aerospace Center) is in charge of the airborne measurements and data evaluation of the microphysical properties of clouds encountered during the SENS4ICE field campaigns in February, March and April 2023. We present the instrumentation that is used in the flight experiments for the characterization of
Jurkat-Witschas, TinaLucke, JohannesSchwarz, CarstenDeiler, ChristophSachs, FalkKirschler, SimonMenekay, DenizVoigt, ChristianeBernstein, BenJaron, OlivierKalinka, FrankZollo, AlessandraLilie, LyleMayer, JohannaPage, Centre Europeen de Recherche et de, ChristianVié, BenoitBourdon, AurelienLima, Rogerio PereiraVieira, Luiz
A new optical array imaging probe, called the 1D2D probe, has been developed by Science Engineering Associates, with features added to improve the real-time and post-analysis measurements of particle spectra, particularly in the Supercooled Large Droplet size range. The probe uses optical fibers and avalanche photodiodes to achieve a very high frequency response, and a Field-Programmable Gate Array that performs real-time particle rejection and processing of accepted particles with negligible inter-particle dead time. The probe records monochromatic two-dimensional images, while also recording the number of individual particle pixels at a second grey scale level. The probe implements flexible features to filter recording of highly out of focus particles to improve the accuracy of particle size determination, or to reject small particles to improve the statistics of measurements of larger particles. A real-time one-dimensional particle spectrum is computed similarly to the original
Lilie, LyleBouley, DanielSivo, ChrisEsposito, BiagioBansemer, AaronHeller, RomyStrapp, J. Walter
The EU Horizon 2020 project SENS4ICE addresses reliable detection and discrimination of supercooled large droplets (SLD) icing conditions. These conditions are considered as particularly safety-relevant and have been included in airplane certification specifications. The SENS4ICE project comprises technology development, icing wind tunnel upgrading/testing and flight testing. A novel hybrid approach for icing detection combines direct sensing (atmospheric conditions / ice accretion) with an indirect technique based on changing aircraft characteristics. The first part of the project was devoted to the development and maturation of icing detection technologies, with a focus on Appendix O (of 14 CFR Part 25 and CS-25) icing conditions. Furthermore, several icing wind tunnel facilities have improved capabilities to represent Appendix O conditions. Icing wind tunnel testing (including Appendix O) of several icing detection sensors developed in the SENS4ICE project concluded the first part
Schwarz, Carsten
This paper presents experimental ice accretion measurements alongside numerical simulations, using the National Research Council Canada’s morphogenetic approach, on a pitot probe geometry at varying icing conditions. In previous publications, the morphogenetic approach for the numerical simulation of ice accretion has shown promise for pitot probe applications, potentially reducing the number of wind tunnel entries, and therefore cost, of the development cycle. An experimental campaign has been completed, providing ice shapes on a representative pitot probe model. Comparison of the experimental and numerical ice shapes indicate that the morphogenetic model is able to generate the complex ice shapes seen experimentally for real-world icing conditions on a fully 3D geometry, closely matching both ice features and total ice thicknesses.
Forsyth, PeterSzilder, Krzysztof
The Current Icing Product (CIP; Bernstein et al. 2005) and Forecast Icing Product (FIP; Wolff et al. 2009) were originally developed by the United States’ National Center for Atmospheric Research (NCAR) under sponsorship of the Federal Aviation Administration (FAA) in the mid 2000’s and provide operational icing guidance to users through the NOAA Aviation Weather Center (AWC). The current operational version of FIP uses the Rapid Refresh (RAP; Benjamin et al. 2016) numerical weather prediction (NWP) model to provide hourly forecasts of Icing Probability, Icing Severity, and Supercooled Large Drop (SLD) Potential. Forecasts are provided out to 18 hours over the Contiguous United States (CONUS) at 15 flight levels between 1,000 ft and FL290, inclusive, and at a 13-km horizontal resolution. CIP provides similar hourly output on the same grid, but utilizes geostationary satellite data, ground-based radar data, Meteorological Terminal Air Reports (METARS), lightning data, and voice pilot
Rugg, AllysonHaggerty, JulieAdriaansen, DanielSerke, DavidEllis, Scott
To support an industry wide response to an EASA proposed Special Condition regarding the threat of in-flight supercooled liquid water icing conditions at altitudes above FL300, Boeing 777 fleet data were used to estimate the frequency and severity of such icing occurrences. The data were from the calendar year 2019 and included ~ 950,000 airline revenue flights from around the world by multiple operators. The unique architecture of the Primary Ice Detection System (PIDS) on that model, in addition to robust meteorological data that was able to be correlated, afforded an opportunity to conservatively estimate the Total Water Exposure (TWE) and thus the Liquid Water Content (LWC) of the icing encounters captured at FL295 and above. This paper will outline the key methods used and present the findings.
Sanford, JeromeBravin, MelissaClarkson, MatthewNatsui, Edward
The Collins Aerospace Optical Ice Detector is a short-range polarimetric cloud lidar designed to detect and discriminate among all types of icing conditions with the use of a single sensor. Recent flight tests of the Optical Ice Detector (OID) aboard a fully instrumented atmospheric research aircraft have allowed comparisons of measurements made by the OID with those of standard cloud research probes. The tests included some icing conditions appropriate to the most recent updates to the icing regulations. Cloud detection, discrimination of mixed phase, and quantification of cloud liquid water content for a cloud within the realm of Appendix C were all demonstrated. The duration of the tests (eight hours total) has allowed the compilation of data from the OID and cloud probes for a more comprehensive comparison. The OID measurements and those of the research probes agree favorably given the uncertainties inherent in these instruments.
Anderson, KaareRay, MarkJackson, Darren
Diagonalized alternating-direction implicit (DADI) method is implemented in the Eulerian hyperbolic droplet solver, ICEPAC, for efficient high-order accurate analysis of aircraft icing. Detailed techniques for implementing the DADI method considering hyperbolicity characteristics are discussed. For the Eulerian droplet equation system to be strictly hyperbolic, additional source terms regarding artificial droplet pressure are included. Validations of the present implicit solver are conducted using two- and three-dimensional steady benchmark tests: NACA0012 airfoil, NACA23012 airfoil, and a swept wing. Also, the oscillating airfoil SC2110 case was analyzed to verify the robustness and efficiency of the proposed solver. In addition, the computational cost of the current implicit solver is considerably lower than that of the explicit multi-stage solver.
Kim, YounghyoHong, YoonpyoShon, SoonhoYee, Kwanjung
In the course of the Horizon 2020 project ICE GENESIS of the European Union, an experimental database was developed to host documentation of icing experiments. The database serves as a source of information for numerical code development and validation as well as future test matrix design, IPS layout and development and wing design. Several legacy data icing cases have been included into the database, which are partly publicly available. Furthermore, the database will serve as the main platform for dissemination of public results of icing cases after and during the project ICE GENESIS. The database itself provides detailed information about the test configurations and the icing wind tunnel. More specifically, CAD data, ice protection system characteristics if applicable, installation in the test facility, instrumentation, test matrix, generated aero-icing conditions and test results are included. Within the ICE GENESIS project, the documentation of the resulting ice accretion is done
Neubauer, ThomasPuffing, Reinhard
Future compliance to FAA 14 CFR Part 25 and EASA CS-25 Appendix O conditions has required icing wind tunnels to expand their cloud simulation envelope, and demonstrate accurate calibration of liquid water content and droplet particle size distributions under these conditions. This has led to a renewed community interest in the accuracy of these calibrations, and the potential inter-facility bias due to the choice of instrumentation and processing methods. This article provides a comparison of the response of various hot-wire liquid water content instruments under Appendix C and supercooled large droplet conditions, after an independent similar analysis at other wind tunnel facilities. The instruments are being used, or are under consideration for use, by facilities collaborating in the ICE GENESIS program. For droplet median volume diameters (MVDs) between about 15 and 250 μm, cylindrical hot wire LWC sensors were found to consistently and increasingly under-read measurements from
Esposito, Biagio M.Orchard, DavidLucke, JohannesNichman, LeonidBliankinshtein, NataliaLilie, LyleCatalano, PietroD'Aniello, FrancescoStrapp, J. Walter
High altitude ice crystals have led to instances of ice accretion on stationary compressor surfaces in aeroengines. Rollback, surge and stall events are known to have been instigated through such accretions due to aerodynamic losses related to ice growth, damage and flameout due to ice shedding. The prevalence of these events has led to a change in certification requirements for icing conditions. Development of accurate numerical models allows the costs of certification and testing to be minimised. An in-house computational code was developed at the Oxford Thermofluids Institute to model glaciated and mixed-phase ice crystal icing. The Ice Crystal Icing ComputationaL Environment (ICICLE) code, comprises a frozen 2D flowfield solution, Lagrangian particle tracking, particle heat transfer and phase change and particle surface interaction modelling. In this paper the ICICLE code is developed into a 3D modelling environment, including 3D particle tracking and modelling of particle wall
Parker, LiamMcGilvray, MatthewGillespie, David
The process for certifying an existing aircraft for flight into known icing is well defined and must follow specific guidelines and meet specific milestones. As UAVs are still a relatively recent development, guidelines for icing flight certification of a UAV have not yet been developed by the FAA, and no UAVs have yet been certified for FIKI under the FAA. As part of a research program, engineers at the Battelle Memorial Institute in Columbus, OH USA worked with partners to integrate its ice protection system, HeatCoatTM, onto an existing UAV platform as a retrofit with the ultimate goal of flying in icing conditions. This research program was funded by the US Government with intent to integrate HeatCoat on the TigerShark-XP UAV. The integration on the TigerShark was demonstrated to present challenges specific to the nature of this UAV that had to be overcome. This research program required simulation of icing accretion using multiple software packages, ground based icing tunnel
Yugulis, KevinChase, DavidKenney, Brian
This paper is focused on the numerical analysis of the impingement and water catch rate of snow particles on the engine air intake of the Next Generation Civil Tilt Rotor (NGCTR). This NGCTR is developed by Leonardo Helicopters. The collection efficiency and water catch rate for the intake geometry are obtained for the test cases that have been defined for the relevant snow conditions. These conditions are related to the flight envelope of the NGCTR, existing EASA/FAA certification specifications, and the snow characterization. The analyses have been performed for the baseline air intake geometry. A range of particle diameters has been simulated with a particle density equal to the density of ice and with a particle drag relation that disregards the particle shape. Based on the results for the water catch rate on the basic nacelle configuration in snow conditions it is concluded that the ‘cheeks’ of the duct are more susceptible to impingement of larger snow crystals (>75 μm), whereas
Kool, NinaVan der Weide, EdwinSpek, Ferdinandvan der Ven, Harmenvan 't Hoff, Stefan
The Icing Research Tunnel at NASA Glenn follows the recommended practice for calibration outlined in SAE’s ARP5905. The calibration team has followed the schedule of a full calibration every five years with a check calibration done every six months following. The liquid water content of the IRT has maintained stability within the stated specifications of variation within +/- 10% of the curve fit equation generated from calibration data. Using past measurements and data trends, IRT characterization engineers wanted to develop methods for the ability to know when data were not within variation. Trends can be observed in the liquid water content measurement process by constructing statistical process control charts. This paper describes data processing procedures for the Multi-Element Sensor in the IRT, including collision efficiency corrections, canonical correlation analysis, process for rejection of data, and construction of control charts. Data are presented to display the control
Timko, EmilyKing-Steen, LauraInsana, Eric
In this work, ice accretion is investigated on a fundamental level using a novel Eulerian phase field approach that captures the phase interface. This method, unlike the Allen-Cahn method, does not lead to spurious phase change (artificial mass loss). This method is also straightforward to implement and avoids normal vector reconstructions along the interface or ghost cells. Additionally, it has well-defined and novel stiffness constraints for accuracy and stability that define parameters in the model such as the kinetic coefficient μ and the interface regularization coefficient γ. An incompressible solver is constructed and used to verify the new method using an analytical Stefan problem solution in both 1D and 2D domains.
Brown, LucyJain, SuhasMoin, Parviz
Large icing wind tunnels typically have sufficient distance for drops from spray nozzles to spread evenly producing small spatial variations of cloud properties at the wind tunnel test section. As the size of a wind tunnel gets smaller, producing clouds with uniform properties becomes challenging because of 1) the reduced distance from the spray bar system to the test section and 2) the spray characteristics of most air-assisted nozzles used for spray generation. For this paper, discrete-phase simulations using FLUENT were used to explore droplet collection on a partial NACA 0012 model at different angles of attack in the Baylor Liquid Film and Cloud Tunnel (LFACT). McClain et al. (2022) used the LFACT to validate a new microwave sensor system to measure collection efficiency variations along the surface of a wind tunnel model. However, the sensors used in the investigation were essentially the same size as the measured non-uniform cloud features in the wind tunnel test section. A
McClain, StephenAhmed, Shakib
The Ice Crystal Environment Modular Axial Compressor Rig (ICE-MACR) was developed by the National Research Council of Canada (NRC) with support from the Federal Aviation Administration (FAA) in response to the need to understand ice crystal icing of aircraft engines at high altitudes. Icing wind tunnel tests on static hardware lack some of the real physics of turbofan compressor such as centrifuging and fracturing of particles, and melting of particles due to compression heating, heat transfer through a casing wall, as well as annular geometry effects. Since the commissioning of ICE-MACR in 2019 new insights have been gained on the physics behind ice crystal icing of turbofan engines. Additionally, the results of various test campaigns have been used to validate engine ice accretion numerical codes. This paper summarizes the key insights into ICI of turbofans gained from the ICE-MACR to date.
Neuteboom, MartinDumont, ChristopherMason, JeanneChalmers, JenniferChow, Philip
In the scope of development or certification processes for the flight under known icing conditions, aircraft have to be tested in icing wind tunnels under relevant conditions. The documentation of these tests has to be performed at a high level of detail. The generated data is used to prove the functionality of the systems, to develop new systems and for scientific purposes, for example the development or validation of numerical tools for ice accretion simulation. One way of documenting the resulting ice geometry is the application of an optical 3D scanning or reconstruction method. This work investigates and reviews optical methods for three-dimensional reconstructions of objects and the application of these methods in ice accretion documentation with respect to their potential of time resolved measurement. Laboratory tests are performed for time-of flight reconstruction of ice geometries and the application of optical photogrammetry with and without multi-light approach. The results
Neubauer, ThomasKozomara, DavidPuffing, ReinhardTeufl, Luca
The National Research Council Altitude Icing Wind Tunnel liquid water content calibrations have historically relied on a 2.4 mm diameter rotating cylinder for drop sizes up to 50 μm and a 6.2 mm diameter rotating cylinder for drop sizes from 50 μm to 200 μm. This study compares the facility calibration, derived from rotating cylinder measurements, to water content measurements from the Science Engineering Associates Multi-Element Probe and the National Research Council Compact Iso-Kinetic Probe over a range of airspeeds and drop sizes. The data show where the rotating cylinder measurements may start to underestimate the liquid water content (LWC), possibly due to splashing at higher airspeeds and drop sizes. The data also show that the LWC read by the Multi-Element Probe is higher than that provided by the rotating cylinders, and the Compact Iso-Kinetic Probe (CIKP) reads higher than both other methods. These trends are consistent with instrumentation comparison data from other icing
Clark, CatherineOrchard, David
Super-cooled large drops present serious threats to aviation safety and as a result, the problem has been addressed by the FAA with the additional icing certification requirement. SLD clouds often consist of bi-modal drop size spectra leading to great challenges when it comes to simulating and characterizing these conditions in situ and in icing wind tunnels. Legacy instrumentation for measuring drop size distributions and liquid water content has been challenged under these conditions. In this report, a high-resolution particle imaging instrument is described; this instrument addresses the need for measuring drop size distributions and liquid water content over a wide range of drop sizes (10 to 2500 μm or larger). A high-throughput megapixel digital camera is used to record shadow images of the particles. High-quality illumination of the particle field is provided with high-power LED illumination with driving electronics designed to provide pulse durations as short as 25ns with
Bachalo, William DonManin, JulienPayne, GregoryFidrich, MichaelIbrahim, Khalid
Multiphase CFD simulations of air and water play a critical role in aircraft icing analysis. Specifically for air data sensors mounted near the front of an aircraft, simulations that predict the concentration of water surrounding an aircraft fuselage are necessary for understanding their performance in icing conditions. Those simulations can aid in sensor design and placement, and are central for defining critical conditions to test during icing qualification campaigns. There are several methods available in CFD that solve a multiphase flow field. Two of the most common methods used are Lagrangian and Eulerian. While these methods are similar, important differences can be viewed in the results, specifically in how the water shadow zones are predicted. This paper compares a Lagrangian and Eulerian CFD method for solving a multiphase flow field, and assesses their performance for use for analyzing installation locations and critical icing conditions of air data probes.
Thangavel, SathishCusher, Aaron
The term “3 inch ice shapes” has assumed numerous definitions throughout the years. At times it has been used to generally characterize large glaze ice accretions on the major aerodynamic surfaces (wing, horizontal stabilizer, vertical stabilizer) for evaluating aerodynamic performance and handling qualities after a prolonged icing encounter. It has also been used as a more direct criterion while determining or enforcing sectional ice shape characteristics such as the maximum pinnacle height. It is the authors’ observation that over the years, the interpretation and application of this term has evolved and is now broadly misunderstood. Compounding the situation is, at present, a seemingly contradictory set of guidance among (and even within) the various international regulatory agencies resulting in an ambiguous set of expectations for design and certification specialists. The focus of this paper is to provide a more complete and accurate historical accounting of “3 inch ice shapes
Leopold, DaveMalone, AdamBosetti, CrisMacomber, JohnSlim, Rami
The simulation of natural-like snow conditions in a controlled environment such as an Icing Wind Tunnel (IWT) is a key component for safe, efficient and cost-effective design and certification of future aircraft and rotorcraft. Current capabilities do not sufficiently match the properties of natural snow, especially in terms of size and morphology. Within the Horizon 2020 project ICE GENESIS, a new technology has been developed aiming to better recreate natural snowflakes. The focus of the newly developed system was the generation of falling snow in a temperature range of +1°C to -4°C. Ground measurements and flight test campaigns have been performed to better characterize these conditions and provide requirements for wind tunnel facilities. The calibration results of the new snow generation system as well as snow accretion data on a NACA0012 test article with a chord length of 0.377 m are presented. The influence of different snow conditions on the accretion rate and the overall shape
Breitfuß, WolfgangFerschitz, HermannSchwarzenboeck, AlfonsHeller, RomyPervier, HugoDupuy, RegisJaffeux, LouisBerne, Alexis
In 2021 the Federal Aviation Administration in collaboration with the National Research Council of Canada performed research on altitude ice crystal icing of aircraft engines using the modular compressor rig, ICE-MACR, in an altitude wind tunnel. The aim of the research campaign was to address research needs related to ice crystal icing of aircraft engines outlined in FAA publication Engine Ice Crystal Icing Technology Plan with Research Needs. This paper reports the findings on ice accretion from a configuration of ICE-MACR with two compression stages. Inherent in two-stage operation is not just additional fracturing and heating by the second stage but also higher axial velocity and potentially greater centrifuging of particles. These factors influence the accretion behavior in the test article compared to single stage accretion. The melt ratio (liquid/total water content) has been shown to be an important parameter in ice crystal icing, with a relatively narrow band of melt ratios
Mason, JeanneNeuteboom, MartinChalmers, JenniferDumont, ChristopherChow, Philip
The measurement and in-flight characterization of atmospheric icing conditions remains a challenging task. This is due to the large variability of microphysical properties of icing conditions. Icing may occur in pure supercooled liquid clouds of various droplet sizes, it may contain freezing drizzle or freezing rain drops and it also takes place in various types of mixed-phase conditions. A sensor or a combination of sensors to discriminate these icing environments would therefore be beneficial. Especially the phase classification of small cloud particles is still difficult to assess. Within the SENS4ICE project, the German Aerospace Center (DLR) suggests the use of the Nevzorov probe and the Backscatter Cloud Probe with Polarization Detection (BCPD) for the detection and differentiation of icing conditions during research missions that lack standard underwing probes. The first research flights with this instrument combination were conducted in March and April 2022 out of Longyearbyen
Lucke, Johannes ReinhardJurkat, TinaBaumgardner, DarrelKalinka, FrankMoser, ManuelDe La Torre Castro, ElenaVoigt, Christiane
The European Union’s Horizon 2020 programme has funded the SENS4ICE (Sensors for Certifiable Hybrid Architectures for Safer Aviation in Icing Environment) international collaboration flagship programme. Under this programme a number of different organizations have developed ice detection technologies, specifically aimed at providing information to differentiate between ‘classical’ Appendix C icing conditions and the larger droplets found in Appendix O icing. As a partner within the SENS4ICE project, AeroTex UK has developed an ice detection concept called the Atmospheric Icing Patch (AIP). The sensor utilizes a network of iso-thermal sensors to detect icing and differentiate between small and large droplet icing conditions. This paper discusses the development of the sensor technology with a focus on the outcomes of the flight testing performed on the Embraer Phenom 300 platform during early 2023. The work in the programme is built on previous studies performed by AeroTex UK into a
Roberts, IanGent, RogerHatch, ColinMoser, Richard
Since the introduction of ice crystal icing certification requirements [1], icing facilities have played an important role in demonstrating compliance of aircraft air data probes, engine probes, and increasingly, of turbine engines. Most sea level engine icing facilities use the freezing-out of a water spray to simulate ice crystal icing conditions encountered at altitude by an aircraft in flight. However, there are notable differences in the ice particles created by freeze-out versus those observed at altitude [2, 3, 4]. Freeze-out crystals are generally spherical as compared to altitude crystals which have variable crystalline shapes. Additionally, freeze-out particles may not completely freeze in their centres, creating a combination of super-cooled liquid and ice impacting engine hardware. An alternative method for generating ice crystals in a test facility is the grinding of ice blocks or cubes to create irregular shaped crystals. These grind-out particles have a different
Neuteboom, MartinFleurent-Wilson, EricChalmers, Jennifer
In-flight icing is a major weather hazard to aviation; therefore, the remote detection of meteorological conditions leading to icing is a very aspired goal for the scientific community. In 2017, the Meteorological Laboratory of CIRA has developed a satellite-based tool for in-flight icing detection in collaboration with Italian Air Force Meteorological Service. Then, in the framework of the European project SENS4ICE, a further maturation of the previously developed algorithm has been achieved, in order to consider also Supercooled Large Drop (SLD) Icing Conditions. The tool relies on high-resolution satellite products based on Meteosat Second Generation (MSG) data. The aim of this product is to identify areas potentially affected by in-flight icing hazard, using information about the properties of clouds, remotely inferred from satellite, and the set of experimental curves and envelopes describing the interrelationship of icing-related cloud variables, that represent the icing
Zollo, Alessandra LuciaBucchignani, Edoardo
Determining local ice crystal icing concentration factors in the region of the forward fuselage is critical for setting the Total Water Content levels for air data probe qualification testing. Simulation, modeling, and testing techniques for this concentration-factor phenomenon are still in their infancy, and there is currently not a significant amount of this type of analysis in the literature. A representative, 3D analysis was conducted using transport airplane geometry and flight conditions that explored the sensitivities resulting from parametric changes to flight and ice crystal icing conditions, particle modeling parameters, and bouncing effects.
Malone, Adam
A fundamental understanding of the icing process for aircraft requires a more thorough analysis of the thermodynamics of supercooled droplet impingement. To better study such thermodynamic processes, a novel temperature sensor that functions within supercooled water and ice crystals was developed. The temperature sensor is non-intrusive and provides temperature and phase change information for both liquid water and solid ice. The temperature sensor is an optical sensor based on the luminophore pyranine. The use of pyranine allows for the measurement of spatially and temporally resolved temperature fields for icing applications. The sensitivity of the sensor is -9.2±0.1%/K for temperature measurement in the solid phase and 0.8±0.1%/K for the liquid phase. The performance of the sensor was demonstrated through a calibration process using spectral analysis, the observation of the melting process of a rectangular prism created from the luminescent ice, and the study of the temperature
Gonzales, JosephYamazaki, MasafumiSakaue, Hirotaka
Protecting against atmospheric icing conditions is critical for the safety of aircraft during flight. Sensors and probes are often used to indicate the presence of icing conditions, enabling the aircraft to exit the icing cloud and engage their ice protection systems. Supercooled large drop (SLD) icing conditions, which are defined in Appendix O of 14 CFR Part 25, pose additional risk to aircraft safety as compared to conventional icing conditions, which are defined in Appendix C of 14 CFR Part 25. For this reason, developing sensors that can not only indicate the presence of ice, but can also differentiate between Appendix O (App O) and Appendix C (App C) icing conditions, is of particular interest to the aviation industry and to federal agencies. Developing a detector capable of meeting this challenge is the focus of SENS4ICE, a European Union sponsored project. This paper summarizes the work that was done to develop the Collins Ice Differentiator System, an ice detection and
Hamman, MatthewRidouane, El HassanGelao, GiancarloChabukswar, RohanBotura, Galdemir
In-flight atmospheric icing is a significant threat to the use of unmanned aerial vehicles (UAVs) in adverse weather. The propeller of the UAV is especially sensitive to icing conditions, as it accumulates ice at a faster rate than the wings of the UAVs. Ice protection systems can be developed to counteract the danger of icing on the propeller of UAVs. In this study, the influence of different meteorological conditions on a propeller of a UAV is analyzed for a UAV with a wingspan of a few meters. The ice accretion and the performance degradation and the required anti-icing heat fluxes have been calculated using numerical methods with ANSYS FENSAP-ICE. This analysis has been used to evaluate the critical conditions for the operation of a UAV in icing conditions and the design of a thermal IPS system for a propeller. The highest ice mass has been found at a temperature of −10 °C and an MVD of 20 μm in intermittent maximum icing conditions. The performance degradation has been the highest
Müller, Nicolas CarloHann, Richard
Innovative carbon nanotube (CNT) electrothermal heating technology for ice protection systems is one of the alternatives under development that shall contribute to more efficient and sustainable aircraft. CNT heater technology allows for more rapid heat up rates over legacy metallic electrothermal heaters that utilize resistance wires or metallic foils. This more rapid heat up rate can lead to more energy efficient electrothermal ice protection system designs and is being studied to determine how much the rapid heat up properties of CNT can lead to a minimization of residual ice build-up aft of the heated area. Due to the inherent redundancy of CNT material used, leads to a very robust and damage tolerant heating element. To mature this technology to prepare to implement CNT on an in-service aircraft platform, a multi-staged flight testing effort to prove out the technology on an actual aircraft and in a relevant environment is mandatory. Recently a major milestone was achieved after
Hein, BrandonBotura, GaldemirHamman, MatthewSlane, Casey
In response to safety regulations regarding aircraft icing, Collins Aerospace has developed and tested a new generation of optical ice detectors (OID Lite) intended to discriminate among icing conditions described by Appendix C and Appendix O of 14 CFR Part 25 and Appendix D of Part 33. The OID Lite is a flush-mounted, short-range, polarimetric optical sensor that samples the airstream up to two meters beyond the skin of the aircraft. The intensity and polarization of the backscatter light correlate with bulk properties of the cloud, such as cloud density and phase. Drizzle-sized droplets, mixed within a small droplet cloud, appear as scintillation spikes in the lidar signal when it is processed pulse-by-pulse. Scintillation in the backscatter (in combination with the outside air temperature monitored by another probe) signals the presence of supercooled large droplets (SLD) within the cloud—a capability incorporated into the OID Lite to meet the requirements of Appendix O. Recent
Ray, MarkAnderson, KaareRamthun, Kent
The present paper showcases the predicting ability of an in-house 2D/ Quasi-3D steady state Ice Crystal Accretion Tool (ICAT) applicable for both heated and un-heated surfaces. The previously existing code for unheated surfaces, has been extended to heated scenarios with the inclusion of: 1) coupling with solid conduction model 2) inclusion of advanced models for crystal melting, water film modeling, sticking and erosion. The results obtained from ICAT are verified against the experimental results of heated NACA0012 airfoil, conducted in the icing wind tunnel of TU Braunschweig as part of MUSIC-haic project. ICAT predictions are found to be well in agreement with the ICI physics, which is proven with the various parameters addressed in this paper, such as tunnel temperature, ice crystal temperature, inlet melt ratio, heating power, etc.
Roychowdhury, SomasreePoornima, RajaniBokade, VilasJebauer, SteffenVanacore, PaoloMalik, Yasir A.
This paper focuses on the design of the thermoelectric ice protection system (IPS) for the engine air intake of the Next Generation Civil Tiltrotor (NGCTR), a demonstrator under development in Leonardo Helicopters. A specific IPS design strategy for the novel intake configuration is proposed. The main constraint which driven the design strategy is a maximum power of 10.6 kW available for the full intake IPS system. The IPS was designed for safe aircraft operations within the Appendix-C icing envelope. The numerical approach adopted to perform the design and the resulting IPS concept are presented. Calculations of the required IPS heat fluxes revealed that maintaining running wet conditions on the entire intake surface is not feasible due to the limitation to the maximum IPS power demand. Therefore, a de-icing IPS design strategy is proposed. The anti-icing mode is adopted only on the lip region to avoid formation of ice caps whereas de-icing zones are defined within the intake duct
Tormen, DamianoZanon, AlessandroDe Gennaro, Michele
Considerable amounts of water accumulate in aircraft fuel tanks due to condensation of vapor during flight or directly during fueling with contaminated kerosene. This can result in a misreading of the fuel meters. In certain aircraft types, ice blocks resulting from the low temperatures at high altitude flights or in winter time can even interfere with the nozzles of the fuel supply pipes from the tanks to the engines. Therefore, as part of the maintenance operations, water has to be drained in certain intervals ensuring that no remaining ice is present. In the absence of an established method for determining residual ice blocks inside, the aircraft operator has to wait long enough, in some cases too long, to start the draining procedure, leading potentially to an unnecessary long ground time. A promising technology to determine melting ice uses acoustic signals generated and emitted during ice melting. With acoustic emissions, mainly situated in the ultrasonic frequency range, a very
Pfeiffer, HelgeReynaert, JohanSeveno, DavidJordaens, Pieter-JanCeyhan, OzlemWevers, Martine
Hazardous atmospheric icing conditions occur at sub-zero temperatures when droplets come into contact with aircraft and freeze, degrading aircraft performance and handling, introducing bias into some of the vital measurements needed for aircraft operation (e.g., air speed). Nonetheless, government regulations allow certified aircraft to fly in limited icing environments. The capability of aircraft sensors to identify all hazardous icing environments is limited. To address the current challenges in aircraft icing detection and protection, we present herein a platform designed for in-flight testing of ice protection solutions and icing detection technologies. The recently developed Platform for Ice-accretion and Coatings Tests with Ultrasonic Readings (PICTUR) was evaluated using CFD simulations and installed on the National Research Council Canada (NRC) Convair-580 aircraft that has flown in icing conditions over North East USA, during February 2022. This aircraft is a flying laboratory
Nichman, LeonidFuleki, DanSong, NaihengBenmeddour, AliWolde, MengistuOrchard, DavidMatida, EdgarBala, KennySun, ZhigangBliankinshtein, NataliaRanjbar, KeyvanDiVito, Stephanie
Thermal ice protection systems (IPS) are used extensively in aeronautics. They are tailored according to the aircraft characteristics or flight envelope and can be used in different modes, anti-icing to avoid ice accretion or de-icing to remove the ice once accreted. A relevant issue by this application is the runback icing, caused by the downstream flow of melted or running water to unprotected areas, where activation is not possible in terms of energy consumption. Passive systems are being explored to complement or replace active systems, although, up to now, solutions have not been reported with the required performance for real-life applications. One of the most commonly reported anti-icing strategy relays on superhydrophobicity, i.e., it is based on the water roll-off capacity of Cassie-Baxter superhydrophobic surfaces (CB-SHP). Precisely, running wet phenomena, where liquid water is flowing on the surface, could be an appropiate application field for this type of materials
Mora, JulioGarcía, PalomaCarreño, FranciscoMontes, LauraLópez-Santos, CarmenRico, VictorBorras, AnaRedondo, FranciscoGonzález-Elipe, Agustín R.Agüero, Alina
Computational icing analysis results were compared to experimental icing tunnel data including aerothermal (e.g., dry air) and supercooled water droplet rime-ice conditions from tests conducted in early 2022 at the NASA Icing Research Tunnel (IRT). The Simulated Inter-compressor Duct Research Model (SIDRM) test article was used in this study, and its geometry represents the inter-compressor duct region of a turbofan engine. The test article’s purpose is to study the physics of supercooled water icing and ice crystal icing. This study compared three different icing codes: FENSAP-ICE (Eulerian approach), LEWICE3D (Lagrangian approach), and GlennICE (Lagrangian approach). All three icing codes were conducted on SIDRM’s complex body flow-field and compared to different experimental supercooled water rime runs. The test article instrumentation (pressure taps, thermocouples, etc.) and 3D laser scans of final ice shapes were used to compare against the different icing code simulations. The
Stewart, EricBartkus, Tadas
The paper describes the upgrade and validation of a Cartesian solver able of estimating the mass deposition of super-cooled large droplets (SLD) on aerodynamic surfaces. A decoupled approach is applied in which the air-flow field is first computed by using a RANS method and then passed to an Eulerian solver for obtaining the water-field. Both tools are based on a finite-volume (FV) approach based on locally refined Cartesian meshes and immersed boundaries. The use of semi-empirical models allow to take into account the primary effects due to splashing and bouncing of large droplets on aerodynamic surfaces. Here, we discuss the results of a numerical campaign with the aim of estimating the accuracy of two mass-deposition models on benchmarks from different experimental databases. Besides, for some cases we compare the present results with the ones obtained by using a body-conforming method.
Capizzano, Francescode Rosa, Donato
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