Browse Topic: Icing and ice detection

Items (847)

Calibration and Acceptance of Icing Wind Tunnels

01/21/2025

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

Optimizing the Capacity of Dozer Blade with Hydraulic Foldable Wings to Enhance Productivity

2024-28-0268

12/05/2024

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 Prakash, Sarma, Neelam Kumar

Minimum Operational Performance Specification for Remote On-Ground Ice Detection Systems

AS5681C (Current)

08/12/2024

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 Detection from Microwave Sensors

TBMG-50648

05/01/2024

Ice build-up on aircraft and wind turbines can impact the safety and efficiency of their systems.

Differentiation between Appendix O and Appendix C Icing Conditions in Flight Using the Collins Ice Differentiator System

2024-01-1933

03/05/2024

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, Matthew, Gelao, Giancarlo, Ridouane, El Hassan, Chabukswar, Rohan, Botura, Galdemir

Assessment of Noncommercial Icing Prediction Capabilities for Army Applications

23AERP12_10

12/01/2023

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

Assessment of Noncommercial Icing Prediction Capabilities for Army Applications

TBMG-49666

12/01/2023

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 – Digital Twinning of a Brake Dynamometer

2023-01-1884

11/05/2023

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

Aircraft Ground Deicing/Anti-Icing Communication Phraseology for Flightcrew and Groundcrew

ARP6257B (Current)09/15/2023

This SAE Aerospace Recommended Practice (ARP) establishes standard phraseology for the communication procedures during aircraft ground deicing/anti-icing operations.NOTE: The minimum requirements to accomplish an aircraft deicing/anti-icing operation are specified in AS6285.Clear concise standard phraseology between the groundcrew and flightcrew is an important part of the deicing/anti-icing process. It plays a key role in the overall safety of the deicing program. Historically, flightcrew and groundcrew have had to deal with differing communication scripts at multiple airport locations. This has led to unsafe situations, including aircraft moving before the deicing process has been fully completed.

G-12M Methods Committee

A Phase Field Model for Simulating the Freezing of Supercooled Liquid Droplets

2023-01-1454

06/15/2023

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, Lucy, Jain, Suhas, Moin, Parviz

3 Inch Ice Shapes, AB Initio

2023-01-1434

06/15/2023

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, Dave, Malone, Adam, Bosetti, Cris, Macomber, John, Slim, Rami

Large-Eddy Simulation of a NACA23012 Airfoil under Clean and Iced Conditions

2023-01-1483

06/15/2023

Predicting the aerodynamic performance of an aircraft in icing conditions is critical as failures in an aircraft’s ice protection system can compromise flight safety. Aerodynamic effects of icing have typically relied on RANS modeling, which usually struggles to predict stall behavior, including those induced by surface roughness. Encouraged by recent studies using LES that demonstrate the ability to predict stall characteristics on full aircraft with smooth wings at an affordable cost [1], this study seeks to apply this methodology to icing conditions. Measurements of lift, drag, and pitching moments of a NACA23012 airfoil under clean and iced conditions are collected at Re = 1.8M. Using laser scanned, detailed representations of the icing geometries, LES calculations are conducted to compare integrated loads against experimental measurements in both clean and iced conditions at various angles of attack through the onset of stall [2]. This study will explore several critical ice

Bornhoft, Brett, Jain, Suhas, Goc, Konrad, Bose, Sanjeeb, Moin, Parviz

UAV Icing: Icing Cases for Validation of Path Planning Method

2023-01-1379

06/15/2023

As part of the complete solution to deal with atmospheric in-flight icing on unmanned aerial vehicles (UAV), a path planner is a valuable tool for finding an optimal path for accomplishing UAV missions. When considering icing conditions, the planner manages areas with icing risk. Together with an electro-thermal ice protection system (IPS), the path planner can optimize energy consumption by comparing energy consumed flying through the cloud or around it, as the UAV can now more safely pass through the ice. The UAV’s aerodynamic stability is also considered by meeting lift requirements, producing enough thrust, and having battery capacity left. These are constraints in the planner to ensure that the UAV can complete its mission. Benchmark icing cases are constructed to validate that the path planner performs as intended. A particle swarm optimization (PSO) is used as a method in the planner due to its ability to handle highly nonlinear problems and to be able to explore the solution

Cheung, Michael, Hann, Richard, Johansen, Tor

Novel Framework for the Robust Optimization of the Heat Flux Distribution for an Electro-Thermal Ice Protection System and Airfoil Performance Analysis

2023-01-1392

06/15/2023

We present a framework for the robust optimization of the heat flux distribution for an anti-ice electro-thermal ice protection system (AI-ETIPS) and iced airfoil performance analysis under uncertain conditions. The considered uncertainty regards a lack of knowledge concerning the characteristics of the cloud i.e. the liquid water content and the median volume diameter of water droplets, and the accuracy of measuring devices i.e., the static temperature probe, uncertain parameters are modeled as uniform random variables. A forward uncertainty propagation analysis is carried out using a Monte Carlo approach. The optimization framework relies on a gradient-free algorithm (Mesh Adaptive Direct Search) and three different problem formulations are considered in this work. Two bi-objective deterministic optimizations aim to minimize power consumption and either minimize ice formations or the iced airfoil drag coefficient. A robust optimization formulation was also considered aiming to

Gallia, Mariachiara, Guardone, Alberto, Congedo, Pietro Marco

Liquid Water Content Instrumentation Study at the NRC AIWT

2023-01-1424

06/15/2023

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, Catherine, Orchard, David

Icing Qualification Wind Tunnel Test of Helicopter Engine with Inlet Barrier Filter Air Intake

2023-01-1381

06/15/2023

Icing wind tunnel testing was performed as part of the Republic of Korea certification of the Light Civil Helicopter (LCH) for inadvertent flight in icing conditions. The test was aimed at the compliance demonstration of the engine and air intake with dry-media Inlet Barrier Filter (IBF) and was performed with an Arriel 2C2 engine in turbojet configuration. Testing took place at the sea level ambient pressure Large Climatic Wind Tunnel (CWT) at Rail Tec Arsenal (RTA) in Vienna, Austria, by an integrated test team comprising engineers from the Royal Netherlands Aerospace Centre (NLR), Korea Aerospace Industries (KAI), and Safran Helicopter Engines. The test matrix covered the AC29-2C Appendix C 10,000 ft icing envelope, as well as simulated ground icing conditions, considering both a clean and artificially contaminated IBF. Beyond the aforementioned certification conditions, exploratory testing was performed in conditions with Supercooled Large Droplets (SLD) and rain. The test set-up

van 't Hoff, Stefan, Lammers, Karel, Jung, Joo Hyun, Kim, Hyung Sik, Ressejac, Sandy

High Resolution Cloud Particle Imaging Incorporating State-of-the-Art Digital Cameras with Pulsed LED Illumination

2023-01-1421

06/15/2023

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 Don, Manin, Julien, Payne, Gregory, Fidrich, Michael, Ibrahim, Khalid

Characterization of Atmospheric Icing Conditions during the HALO-(AC) ³ Campaign with the Nevzorov Probe and the Backscatter Cloud Probe with Polarization Detection

2023-01-1485

06/15/2023

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 Reinhard, Jurkat, Tina, Baumgardner, Darrel, Kalinka, Frank, Moser, Manuel, De La Torre Castro, Elena, Voigt, Christiane

Simulation of Drop Collection with Non-Uniform Cloud Distributions for Collection Efficiency Sensor Validation

2023-01-1405

06/15/2023

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, Stephen, Ahmed, Shakib

Time Resolved 3D Scanning of Ice Geometries in a Large Climatic Wind Tunnel

2023-01-1414

06/15/2023

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, Thomas, Kozomara, David, Puffing, Reinhard, Teufl, Luca

Ice Crystal Environment - Modular Axial Compressor Rig: Comparisons of Ice Accretion for 1 and 2 Stages of Compression

2023-01-1397

06/15/2023

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, Jeanne, Neuteboom, Martin, Chalmers, Jennifer, Dumont, Christopher, Chow, Philip

A Comparison of Multiphase Flow CFD Methods for Simulating Liquid Water Concentration at Air Data Probe Fuselage Stations

2023-01-1390

06/15/2023

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, Sathish, Cusher, Aaron

NRC’s ICE-MACR 2018-2023: What Has Been Learned So Far

2023-01-1377

06/15/2023

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, Martin, Dumont, Christopher, Mason, Jeanne, Chalmers, Jennifer, Chow, Philip

Experimental Simulation of Natural-Like Snow Conditions in the Rail Tec Arsenal (RTA) Icing Wind Tunnel

2023-01-1407

06/15/2023

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, Wolfgang, Ferschitz, Hermann, Schwarzenboeck, Alfons, Heller, Romy, Pervier, Hugo, Dupuy, Regis, Jaffeux, Louis, Berne, Alexis

Comparison of Freeze-Out versus Grind-Out Ice Crystals for Generating Ice Accretion Using the ICE-MACR

2023-01-1418

06/15/2023

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, Martin, Fleurent-Wilson, Eric, Chalmers, Jennifer

Development of the Atmospheric Icing Patch (AIP) under the SENS4ICE Programme

2023-01-1488

06/15/2023

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, Ian, Gent, Roger, Hatch, Colin, Moser, Richard

Experimental Investigation of a CRM65 Wingtip Mockup under Appendix C and Appendix O Icing Conditions

2023-01-1386

06/15/2023

Research institutes and companies are currently working on 3D numerical icing tools for the prediction of ice shapes on an international level. Due to the highly complex flow situation, the prediction of ice shapes on three-dimensional surfaces represents a challenge. An essential component for the development and subsequent validation of 3D ice accretion codes are detailed experimental data from ice shapes accreted on relevant geometries, like wings of a passenger aircraft for example. As part of the Republic of Austria funded research project JOICE, a mockup of a wingtip, based on the National Aeronautics and Space Administration common research model CRM65 was designed and manufactured. For further detailed investigation of electro-thermal de-icing systems, various heaters and thermocouples were included. The mockup was investigated in the Icing Wind Tunnel of Rail Tec Arsenal in Vienna, Austria under various Appendix C and Appendix O icing conditions with and without activated

Puffing, Reinhard, Neubauer, Thomas, Moser, Richard, Hassler, Wolfgang, Schweighart, Simon, Ferschitz, Hermann, Diebald, Stefan, Breitfuss, Wolfgang, Kozomara, David

Design and Testing of an Indirect Ice Detection Methodology

2023-01-1493

06/15/2023

Distinct atmospheric conditions containing supercooled large droplets (SLD) have been identified as cause of severe accidents over the last decades as existing countermeasures even on modern aircraft are not necessarily effective against SLD-ice. Therefore, the detection of such conditions is crucial and required for future transport aircraft certification. However, the reliable detection is a very challenging task. The EU funded Horizon 2020 project SENS4ICE targets this gap with new ice detection approaches and innovative sensor hybridization. The indirect ice detection methodology presented herein is key to this approach and based on the changes of airplane flight characteristics under icing influence. A performance-based approach is chosen detecting an abnormal flight performance throughout the normal operational flight. It is solely based on a priori knowledge about the aircraft characteristic and the current measurable flight state. This paper provides a proof of concept for the

Deiler, Christoph, Sachs, Falk

Multi-Physics Simulations of Ice Shedding from Wind Turbines

2023-01-1479

06/15/2023

Wind turbines in cold climates are likely to suffer from icing events, deteriorating the aerodynamic performances of the blades and decreasing their power output. Continuous ice accretion causes an increase in the ice mass and, consequently, in the centrifugal force to which the ice shape is subjected. This can result in the shedding of chunks of ice, which can jeopardize the aeroelastic properties of the blade and, most importantly, the safety of the surrounding people and of the wind turbine structure itself. In this work, ice shedding analysis is performed on a quasi-3D, multi-step ice geometry accreted on the NREL 5MW reference wind turbine. A preliminary investigation is performed by including the presence of an ice protection system to decrease the adhesion surface of the ice on the blade. A reference test case with a simple geometry is used as verification for the correct implementation of the procedure. The procedure was shown to be robust and will be used in the future within

Rausa, Andrea, Caccia, Francesco, Guardone, Alberto

Design, Characterization and Initial Testing of a Vertical Stabilizer Common Research Model for Aircraft Ground Icing Testing

2023-01-1439

06/15/2023

Under contract to Transport Canada (TC) and with joint funding support from the Federal Aviation Administration (FAA), a vertical stabilizer common research model (VS-CRM) has been designed and built by the National Research Council of Canada (NRC). This model is a realistic, scaled representation of modern vertical stabilizer designs without being specific to a particular aircraft. The model was installed and tested in the NRC 3 m × 6 m Icing Wind Tunnel in late 2021/early 2022. Testing was led by APS Aviation Inc., with support from NRC and NASA, in order to observe the anti-icing fluids flow-off behavior with and without freezing or frozen precipitation during simulated take-off velocity profiles. The model dry-air aerodynamic properties were characterized using flow visualization tufts and boundary layer rakes. Using this data, a target baseline configuration was selected with a yaw angle equal to 0° and rudder deflection angle equal to -10°. Testing with fluids and precipitation

Clark, Catherine, Ruggi, Marco

Influence of Realistic Aircraft Conditions on Accretion of Supercooled Large Droplet

2023-01-1408

06/15/2023

The present paper deals with the accretion of supercooled large droplets (SLD) at high velocity on wall. A visualization technique of the accretion of ice is used to measure and characterize the thickness of ice during the accretion phenomenon. Influences of air velocity, air temperature, drop size, impact angle and altitude were studied. The experiments are conducted in the ONERA icing wind tunnel, which allows to reach regimes close to realistic conditions for aircrafts (i.e. high velocity: → 190 m/s and altitude: → 11 500 m).

Dejean, Baptiste, Alary, Thomas, Duchayne, Quentin, Berthoumieu, Pierre

Effect of Surface Modification on the Hybrid Ice Protection Systems Performances

2023-01-1452

06/15/2023

The formation of ice can be very detrimental to flight safety, since the ice accumulated on the surfaces of the aircraft can alter both the aerodynamics and the weight, leading in some cases to catastrophic lift reductions. Traditional active Ice Protection Systems (IPS) require high energy to work, add on weight to the aircraft and complexity to the manufacturing. On the other hand, the use of passive IPS, such as superhydrophobic/icephobic coatings, cannot be successful in harsh environmental conditions or for prolongated icing expositions. So, a valuable solution could be the combination of active and passive IPS with the aim to combine the advantage of both of them and mitigate their drawbacks. In this context, the present work proposes two innovative Hybrid IPS, based on an ultrasound piezoelectric system and on a thermoelectric system manufactured using carbon fibers as heater elements, both combined with a superhydrophobic coating with the aim to study the effect of the surface

Piscitelli, Filomena, Ameduri, Salvatore, Volponi, Ruggero, Pellone, Lorenzo, De Nicola, Felice, Concilio, Antonio, Albano, Floriana, Elia, Gianpaolo, Notarnicola, Lorenzo

Numerical Heat Transfer Simulations for Laser-Scanned Ice Shapes

2023-01-1448

06/15/2023

Ice accretions on aircraft flight surfaces can degrade lift, increase drag, and reduce controllability. Anti-icing systems can remove or prevent ice growth. To predict the ice shrinkage or accretion using models such as LEWICE, the convective heat transfer behavior at the ice surface must be quantified. The work here is focused on understanding the convective heat transfer for several laser-scanned ice shapes by using commercial computational fluid dynamics (CFD) heat transfer simulations. The leading edge ice shape from a NACA 0012 airfoil and its geometrically unwrapped simplification are studied. Limitations encountered with a semi-automated unstructured mesh generation tool are presented. Thin boundary layer mesh thicknesses (i.e. much thinner than the flow’s viscous or thermal boundary layers) are found to be necessary in order to capture the surface curvature features and preserve good mesh quality near the geometric surface. To better model a prior experiment, the unwrapped

Feier, Ioan

3D Immersed Boundary Methods for the Calculations of Droplet Trajectories towards Icing Application

2023-01-1458

06/15/2023

The in-flight ice accretion simulations are typically performed using a quasi-steady formulation through a multi-step approach. As the ice grows, the geometry changes, and an adaptation of the fluid volume mesh used by the airflow and droplet-trajectory solver is required. Re-meshing or mesh deformation are generally employed to do that. The geometries formed are often complex ice shapes increasing the difficulty of the re-meshing process, especially in three-dimensional simulations. Consequently, difficulties are encountered when trying to automate the process. Contrary to the usual body-fitted mesh approach, the use of immersed boundary methods (IBMs) allows solving, or greatly reducing, this problem by removing the mesh update, facilitating the global automation of the simulation. In the following paper, an approach to perform the airflow and droplet trajectory calculations for three-dimensional simulations is presented. This framework utilizes only immersed boundary methods. In

Elices Paz, Pablo, Radenac, Emmanuel, Péron, Stéphanie, Blanchard, Ghislain, Laurendeau, Eric, Villedieu, Philippe

Development of an Altitude Evaporation Model for Icing Tunnel Control

2023-01-1425

06/15/2023

In 2017 the National Research Council of Canada developed an evaporation model for controlling engine icing tunnels in real time. The model included simplifications to allow it to update the control system once per second, including the assumption of sea level pressure in some calculations. Recently the engine icing system was required in an altitude facility requiring operation down to static temperatures of -40°C, and up to an altitude of 9.1 km (30 kft) or 30 kPa. To accommodate the larger temperature and pressure range the model was modified by removing the assumption of sea level operation and expanding the temperature range. In addition, due to the higher concentration of water vapor that can be held by the atmosphere at lower pressures, the significance of the effect of humidity on the air properties and the effect on the model was investigated. The effect of humidity on the density, specific heat, viscosity, thermal conductivity and Prandtl number of air compared to assuming

Davison, Craig

Roughness Parameter Optimization of the McClain Model in GlennICE

2023-01-1468

06/15/2023

Aircraft icing remains a significant threat to aviation safety. Software that predicts the impingement and ice accretion on full aircraft geometries and aircraft components are in demand and NASA Glenn is committed to produce software that meets this need. One of the key parameters affecting an accurate prediction of iced geometry is the effect of ice roughness on the heat transfer coefficient. While many efforts have been made to implement the roughness in the flow solver, this report takes a correlation for roughness height distribution that is based on experimental measurements and demonstrates how to relate those measurements to an augmentation to the heat transfer coefficient provided by the flow solution. The outcome of this effort was the callibration of defaults for user supplied parameters to this correlation through comparison with 95 large glaze conditions from experiment by adjusting user-supplied parameters in the roughness augmentation equation.

Wright, William, Rigby, David, Ozoroski, Thomas

Engine Cascade Rig Design Tests and Results in App C Conditions

2023-01-1419

06/15/2023

Current modelling capability for engine icing accretion prediction is still limited for App. C. To further validate icing codes in complex engine geometries, it is necessary to perform additional experimental work in relevant geometrical and environmental conditions. Within the frame of ICE GENESIS [1], an experiment has been setup to replicate the condition at the inlet of an engine first stage compressor. This paper describes the choices for the design of the engine compressor model, the setup within the icing wind tunnel and the methodology employed to obtain the results. Additionally, more effort has been focused on obtaining accurate ice shapes using a 3D scanning system. Results of 3D scans are given.

Pervier, Hugo, Vénuat, Clément, Neubauer, Thomas

Snow Particle Characterization. Part B: Morphology Dependent Study of Snow Crystal 3D Properties Using a Convolutional Neural Network (CNN)

2023-01-1486

06/15/2023

This study presents the results of the ICE GENESIS 2021 Swiss Jura Flight Campaign in a way that is readily usable for ice accretion modelling and aims at improving the description of snow particles for model inputs. 2D images from two OAP probes, namely 2D-S and PIP, have been used to extract 3D shape parameters in the oblate spheroid assumption, as there are the diameter of the sphere of equivalent volume as ellipsoid, sphericity, orthogonal sphericity, and an estimation of bulk density of individual ice crystals through a mass-geometry parametrization. Innovative shape recognition algorithm, based on Convolutional Neural Network, has been used to identify ice crystal shapes based on these images and produce shape-specific mass particle size distributions to describe cloud ice content quantitatively in details. 3D shape descriptors and bulk density have been extracted for all the data collected in cloud environments described in the regulation as icing conditions. They are presented

JAFFEUX, Louis, Coutris, Pierre, Schwarzenboeck, Alfons, Dezitter, Fabien

Electro-Mechanical Resonant Ice Protection Systems: Numerical Prediction and Experimental Verification of the De-icing of a NACA 0024 Airfoil

2023-01-1389

06/15/2023

This paper proposes an extension to curved surfaces of a design method of piezoelectric ice protection systems established for planar surfaces. The method is based on a finite element analysis which enables the fast computation of the resonant modes of interest to de-ice surfaces as leading edges. The performance of the modes of interest is assessed according to their deicing capacity estimated from the electro-mechanical coupling between the electric charge of the piezoelectric actuators and the strain energy in the structure. The method is illustrated on a NACA 0024 airfoil. Several experimental tests are conducted in an icing wind tunnel to verify the numerical predictions of the ice shedding and the operation of the system.

Palanque, Valerian, Pothin, Jason, Budinger, Marc, Pommier-Budinger, Valérie, Yaich, Ahmed

Data-driven Roughness Estimation for Glaze Ice Accretion Simulation

2023-01-1449

06/15/2023

In-flight ice accretion on aircraft is a major weather-related threat. Industries use both experimental investigations in icing conditions and ice accretion solvers based on computational fluid dynamics (CFD) for aircraft development. An ice accretion solver couples airflow over the geometry, water droplets impingement, and phase change to compute the ice accretion. Such a solver usually relies on a two-equation model: a mass balance and an energy balance. Past studies highlighted the importance of the roughness-sensitive convective heat loss for energy balance. Uncertainties persist in the CFD models given the complexity of the ice accretion phenomenon, which usually mixes solid ice with liquid runback water (glaze ice). A major uncertainty is related to the surface roughness pattern, which is difficult to measure in experiments. The calibration of the roughness pattern for a CFD test case was seldom investigated in literature. Among the available calibration tools, the Bayesian

Ignatowicz, Kevin, Morency, François, Beaugendre, Héloïse

UAV Icing: Experimental Validation Data for Predicting ice Shapes at Low Reynolds Numbers

2023-01-1372

06/15/2023

Icing is a severe hazard to aircraft and in particular to unmanned aerial vehicles (UAVs). One important activity to understand icing risks is the prediction of ice shapes with simulation tools. Nowadays, several icing computational fluid dynamic (CFD) models exist. Most of these methods have been originally developed for manned aircraft purposes at relatively high Reynolds numbers. In contrast, typical UAV applications experience Reynolds numbers an order of magnitude lower, due to the smaller airframe size and lower airspeeds. This work proposes a set of experimental ice shapes that can serve as validation data for ice prediction methods at low Reynolds numbers. Three ice shapes have been collected at different temperatures during an experimental icing wind tunnel campaign. The obtained ice shapes represent wet (glaze ice, −2 °C), mixed (−4 °C), and dry (rime ice, −10 °C) ice growth regimes. The Reynolds number is between Re=5.6…6.0×105, depending on the temperature. The ice shapes

Hann, Richard, Müller, Nicolas, Lindner, Markus, Wallisch, Joachim

Icing Environment Comparisons for the Distinct Parts of Jet Aircraft

2023-01-1429

06/15/2023

Distinct parts of the aircraft may be exposed to different icing conditions due to varying flow and ambient conditions around them. These differences can be easily noticed, especially when icing conditions on the external surface and inside the engine air intake are compared for a jet aircraft. In this paper, the icing conditions around these parts are matched to between them. The purpose of this comparison study is to evaluate the functionality of ice detectors, located inside the air inlets, in detecting icing conditions around external surfaces as well. These systems provide information to the flight crew and/or airplane systems concerning inflight icing. On jet fighter or trainer type aircraft, they are generally located inside the engine air intake that serve as a warning equipment for icing risks on the aircraft engine itself. Sometimes, their warnings are also valid for intake lip ice detection if they are properly located. However, the usage of this equipment for ice detection

Akbal, Omer, Ayan, Erdem, Murat, Canibek, Ozgen, Serkan

Numerical Simulation of In-flight Icing by Water Droplets with Elevated Temperature

2023-01-1477

06/15/2023

When conducting experiments in icing wind tunnels (IWTs), a significant question is to what extent the temperature of the water droplets generated by the spray system has converged to the static air temperature when the droplets impinge on the test object. This is a particularly important issue for large droplets, since the cooling rate of droplets decreases sharply with increasing diameter. In this paper, on the one hand, realistic droplet temperature distributions in the measurement section of the Rail Tec Arsenal IWT (located in Vienna) are computed by means of a numerical code which tracks the paths of the droplets from the spraying nozzle to the measurement section and simultaneously calculates their cooling rates. On the other hand, numerical icing simulations are performed to investigate to what extent the deviation of the droplet temperature from static air temperature influences icing and thermal anti-icing processes. For this purpose, three selected cases are analyzed – two

Hassler, Wolfgang, Breitfuß, Wolfgang, Rapf, Andreas, Fallast, Arno, Moser, Richard, Tramposch, Andreas, Ferschitz, Hermann, Puffing, Reinhard, Neubauer, Thomas

Dynamic and Static Test Methods: Quantifying the Shear Strength at the Interface of Iced Substrates

2023-01-1451

06/15/2023

Surfaces with low ice adhesion are crucial for many technological and societal applications. However, comparing the performance of different surface coatings still represents a major challenge, given the broad range of ice accretion and removal conditions. One of the most common methodologies relies on measuring ice adhesion, which is often quantified by the shear strength of the ice-substrate interface. Nevertheless, large discrepancies up to one order of magnitude exist among the shear strength values reported in the literature for similar test conditions. This work compares shear strength measurements between two inherently different ice adhesion measurement techniques: (i) a dynamic, vibratory approach and (ii) a more traditional static push test on a horizontal surface. By employing a hybrid experimental and numerical approach, the shear strength is obtained for both techniques. This approach allows a direct correlation between a low-complexity static setup and a dynamic test rig

Stendardo, Luca, Gastaldo, Giulia, Budinger, Marc, Antonini, Carlo, Pommier-Budinger, Valérie, Ospina Patiño, Anny Catalina

Passive Ice Protection Systems Lab Scale Testing Methodology

2023-01-1412

06/15/2023

Aircraft icing is a well-known problem that can have serious consequences for flight safety. To combat this problem, various ice protection systems (IPSs) have been developed and are currently used on most aircraft, including thermal ice protection systems. However, these systems can be costly, heavy and ineffective. Therefore, there is a need to improve the efficiency and response time of these systems. In recent years, research has focused on the development of hybrid systems that combine different ice protection technologies to achieve better performance. In this sense, the use of an active element with a coating on its external part that improve its efficiency would be an important advance, but there is a wide range of active systems and even more of coatings and surface treatments. Therefore it would be helpful to have a test methodology that would allow a simple but thorough assessment of the performance of each passive system, and this is precisely what is proposed in this

García, Paloma, Mora, Julio, Carreño, Francisco, Redondo, Francisco, Rodriguez, Rafael, Rivero, Pedro, Vicente, Adrian, Acosta, Carolina, Larumbe, Silvia, Medrano, Ángel, Lecumberri, Cristina

Development of a New Ice Crystal Icing Shear Adhesion Rotary Test Rig and Method

2023-01-1426

06/15/2023

This paper discusses the development and implementation of a new ice crystal icing (ICI) ice adhesion test system and technique. It is based on the state of the art rotary shear adhesion test rig developed at the NRC altitude icing wind tunnel (AIWT) used for supercooled liquid water (SLW) ice accretion adhesion testing. This rig was modified to use strain gauged arms for shed force measurements and implemented into the NRC ICI cascade rig at its research altitude test facility (RATFac). This permitted the exposure to a wide range of ICI conditions both in supercooled and wetbulb below freezing ICI conditions. The result is a standalone system that can be run remotely thus improving the testing efficiency by avoiding the need for accretion calibration points previously required to correlate accreted mass to icing exposure time. This technique was shown to be very repeatable with adhesion results for repeat points generally being within ±4 kPa and being highly sensitive in being able to

Fuleki, Dan, Hagerman, Philip

UAV Icing: Intercycle Ice Effects on Aerodynamic Performance

2023-01-1400

06/15/2023

Atmospheric in-flight icing poses a challenge to all aircraft including unmanned aerial vehicles (UAVs). Aircraft should avoid icing conditions unless they have ways of mitigating the negative effects of icing, e.g., if they are equipped with an ice protection system (IPS). When de-icing systems are used, a certain amount of ice is allowed to accumulate before it is removed. This intercycle ice deteriorates the aerodynamics by reducing the lift, adding mass, and increasing the drag. This study combines the energy that is required to compensate for the added drag of intercycle ice shapes with the energy required for a wing IPS and compares the energy needs for different IPS operations. Two different kinds of intercycle ice shapes are simulated numerically using FENSAP-ICE, one ice shape that would accrete on an unprotected wing and one ice shape that would accrete when using a parting strip, a continuously heated element at the leading edge. The results show that both intercycle ice

Wallisch, Joachim, Hann, Richard

Investigation of the Influence of Aero-Thermal Non-equilibrium Conditions of an SLD Cloud on Airfoil Icing

2023-01-1406

06/15/2023

This study examines the impact of slip in aero-thermal conditions of supercooled large droplets (SLD) produced in an Icing Wind Tunnel (IWT) on the ice accretion characteristics. The study identifies potential biases in the SLD model development based on IWT data and numerical predictions that assume the SLD to be in aerothermal equilibrium with the IWT airflow. To obtain realistic temperature and velocity data for each droplet size class in the test section of the Braunschweig Icing Wind Tunnel (BIWT), a Lagrangian droplet tracking solver was used within a Monte Carlo framework. Results showed that SLDs experience considerable slips in velocity and temperature due to their higher inertia and short residence time in the Braunschweig IWT. Large droplets were found to be warmer and slower than the flow in the test section, with larger droplets experiencing larger aerothermal slips. To examine the impact of these slips, numerical ice accretion simulations were performed on a NACA 0012

Bora, Venkateshwar Reddy, Gallia, Mariachiara, Knop, Inken, Guardone, Alberto

A Comprehensive Numerical Model for Numerical Simulation of Ice Accretion and Electro-Thermal Ice Protection System in Anti-icing and De-icing Mode, with an Ice Shedding Analysis

2023-01-1463

06/15/2023

This work presents a comprehensive numerical model for ice accretion and Ice Protection System (IPS) simulation over a 2D component, such as an airfoil. The model is based on the Myers model for ice accretion and extended to include the possibility of a heated substratum. Six different icing conditions that can occur during in-flight ice accretion with an Electro-Thermal Ice Protection System (ETIPS) activated are identified. Each condition presents one or more layers with a different water phase. Depending on the heat fluxes, there could be only liquid water, ice, or a combination of both on the substratum. The possible layers are the ice layer on the substratum, the running liquid film over ice or substratum, and the static liquid film between ice and substratum caused by ice melting. The last layer, which is always present, is the substratum. The physical model that describes the evolution of these layers is based on the Stefan problem. For each layer, one heat equation is solved

Gallia, Mariachiara, Rausa, Andrea, Martuffo, Alessandro, Guardone, Alberto

Multi-step Ice Accretion by Immersed Boundaries

2023-01-1484

06/15/2023

The paper describes a tools’ suite able of analyzing numerically 3D ice-accretion problems of aeronautical interest. The methodology consists of linking different modules each of them performing a specific function inside the ice-simulation chain. It has been specifically designed from the beginning with multi-step capability in mind. Such a feature plays a key role when studying the dynamic evolution of the icing process. Indeed, the latter has the character of a multi-physic and time-dependent phenomenon which foresees a strong interaction of the air- and water fields with the wall thermodynamics. Our multi-layer approach assumes that the physical problem can be discretized by a series of pseudo-steady conditions. The simulation process starts with the automatic generation of a Cartesian three-dimensional mesh which represents the input for the immersed boundary (IB) RANS solver. Once obtained, the air-phase is used by the Eulerian tool to solve the transport of the water-phase on

de Rosa, Donato, Capizzano, Francesco, Cinquegrana, Davide

Items per page:

1 – 50 of 847