Browse Topic: Icing and ice detection

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Wetting prediction of power train components under the influence moving components using smooth particle hydrodynamics2026-26-03841/16/2026
Passenger cars are subjected to extensive conditions ranging from driving through wet roads, water puddles, icy roads, and rain. This can affect the performance of different parts over time, one such aspect is the vehicle corrosion, whose impact is felt on a wide spectrum from aesthetics to safety due to loss of material. The general condition for corrosion mainly requires electrolyte to be present on the metal surface, which is transported through self-soiling and foreign soiling. Vehicle soiling is an important aspect for vehicle design. Amongst the many aspects of vehicle soiling, one important aspect is the prediction of water accumulation that enables prediction of corrosion sensitive regions in the vehicle. Power train components like Engine, transmission and corresponding wiring harness are at highest risk of water-wetting, As the vehicle drives through the water pool the components are not just wet by the direct inflow of water but also by water being splashed by moving
Shukrey, Sarthak, Pattankar, Rohan, Yenugu, Srinivasa
Design Solutions for Ice-Induced CNG Filling Failures: Field Issue Resolution through Filter Geometry and Seal Material Reengineering2026-26-05151/16/2026
Compressed Natural Gas (CNG) systems in automotive applications are highly sensitive to fuel quality, especially with respect to moisture content. Field issues were observed where high moisture levels in the CNG led to the formation of ice inside the receptacle during refueling operations. This ice formation obstructed the CNG filling process and adversely impacted the sealing performance of the O-ring, particularly under low-temperature conditions induced by pressure differentials between the storage tank and the filling station. Investigation revealed that the existing tablet-type filter design contributed to moisture entrapment within its wire mesh, exacerbating ice formation within the receptacle. To address this, the filter design was modified from a tablet-type to a cup-type filter, significantly reducing the likelihood of moisture retention and subsequent ice formation. Additionally, the O-ring material was upgraded to a formulation with improved sealing properties at lower
Virmani, Nishant, Sawant, Shivraj Madhukar, C R, ABHIJITH
Water Spray and High Humidity Endurance Test Methods for AMS1424 and AMS1428 Aircraft Deicing/Anti-Icing FluidsAS5901E (Current)11/26/2025
This document establishes the minimum requirements for an environmental test chamber, and test procedures to carry out anti-icing performance tests according to the current materials specification for aircraft deicing/anti-icing fluids. The primary purpose for such a test method is to determine the anti icing endurance under controlled laboratory conditions of AMS1424 Type I and AMS1428 Type II, III, and IV fluids.
G-12ADF Aircraft Deicing Fluids
An Overview of Applied Methodology in the Gathering and Analysis of Rotorcraft Cold Weather Encounters DataF-0081-2025-04215/20/2025
Civil and military rotorcraft operators desire enhanced capabilities from their vehicles in terms of mission efficiency, effectiveness, productivity, and availability. A critical element of this challenge is associated with providing cold weather availability. Currently, cold weather operations are enabled by regulatory actions leading to Limited Approvals, Qualifications, Clearances, and Restrictions. Cold weather certification (clearance of a new aircraft) and continuing airworthiness (maintaining effectiveness of fielded aircraft) are data driven processes. This work provides guidance on an Icing Encounters Survey (IES) based data gathering method supporting continuing airworthiness organizations in improving fleet safety and capabilities during cold weather operations.
Alexander, Marc
Rotor Icing and De-icing at DLR's Whirl Tower Test FacilityF-0080-2024-13175/7/2024
The paper presents recent and ongoing activities of the German Aerospace Center (DLR) focusing on experimental icing investigations within the nationally funded project InTEnt-H (2018-2022) and progressive activities in continuing internal DLR projects. The aim of InTEnt-H was to investigate innovative de-icing and anti-icing technologies for small and medium-weight helicopters, for which no rotor de-icing technologies exist to date, and to demonstrate the effectiveness of these systems in a suitable test facility. For this purpose, the whirl tower test facility of the DLR in Braunschweig has been converted into an icing test facility that is unique in Europe and will allow for the generation of atmospheric icing conditions. In this facility, de-icing and anti-icing systems for rotor blades can be tested under centrifugal loads and various icing conditions. The paper starts with a short presentation of the retrofitting works at the DLR whirl tower test facility and its major components
Bartels, Rainer, Konrath, Robert, Keimer, Ralf, Sahyoun, Dominic, Schneider, Oliver, Kalow, Steffen
Numerical Analysis of Rotor Aero-acoustic Characteristics for Ice Detection based on the HMB SolverF-0074-2018-127105/7/2024
ABSTRACT In this work, iced rotors are studied to develop insight in the potential of acoustics-based ice detection. Based on the HMB CFD solver, approximate iced shapes are used and results are analyzed using the FW-H method. Several candidate monitoring positions are assessed for acoustic sensors to be placed on the helicopter fuselage. The influence of ice on the aero-acoustic characteristics of a rotor is calculated, and parameters such as the ice amount and the icing position on the blade are quantified.
Chen, Xi, Barakos, George, Zhao, Qijun
Control Margin Awareness of the AW609 TiltRotor under Asymmetric Aerodynamic Flight ConditionsF-0074-2018-127915/7/2024
ABSTRACT The ability to model and evaluate aircraft performance prior to flight has generated a significant increase in safety margin in the flight testing of experimental aircraft. Prior to the artificial icing campaign for the AW609 aircraft, a flight model of predicted aerodynamic behavior was used to rapidly generate a control margin monitoring and warning system, which was implemented on-board the aircraft during testing to provide awareness of predicted aircraft behavior under icing conditions.
Xiao, Sid, Belt, David, D'Ettorre, Pietro, Edwards, Paul
Drag Performance Degradation Due to Icing of eVTOLF-0078-2022-175335/10/2022
ABSTRACT
McKillip, Robert, Karli, Geoffrey, Yan, Sihong, Palacios, Jose
eVTOL Accretion Modeling for Supporting Algorithmic Icing DetectionF-0076-2020-1629710/5/2020
eVTOL aircraft operating within the air transportation system will undoubtably be exposed to inclement and adverse weather conditions, which may well include operation in icing conditions, whether planned or encountered inadvertently. Design compromises necessary to provide VTOL operations may make continued operation in an icing environment particularly challenging, especially for eVTOL aircraft having only limited excess power for operation of anti-icing or deicing equipment. This paper describes a research program to assess the impact of accreted icing on the performance of eVTOL aircraft, as part of a program for implementation of an Icing Detection Filter that leverages detailed knowledge of that performance impact on the distributed electrical propulsion and lift systems on the vehicle. Modeling approaches for prediction of icing accretion and the associated performance losses, particularly as they can be measured through monitoring of the onboard electrical power system, are
Jr., Robert, Kaufman, Andrew, Quackenbush, Todd
Leaf-Inspired Surface Prevents Frost FormationTBMG-368585/1/2020
Researchers have discovered a new way to significantly reduce frost formation on any surface. The finding could help decrease the amount of energy needed for defrosting and could potentially result in fewer canceled flights, which can be grounded by even the slightest layer of frost.
Unsettled Topics in Unmanned Aerial Vehicle IcingEPR20200084/27/2020
Unmanned aerial vehicles (UAVs) are an emerging technology with a large variety of commercial and military applications. In-flight icing occurs during flight in supercooled clouds or freezing precipitation and is a potential hazard to all aircraft. In-flight icing on UAVs imposes a major limitation on the operational envelope. This report describes the unsettled topics related to UAV icing. First, typical UAV applications and the general hazards of icing are described. Second, an overview of the special technical characteristics of icing on autonomous and unmanned aircraft is given. Third, the operational challenges for flight in icing conditions are discussed. Fourth, technologies for ice protection that mitigate the icing hazard are introduced. Fifth, the tools and methods required to understand UAV icing and to develop aircraft with cold-weather capabilities are presented. Finally, an assessment of the current and future regulations regarding icing on UAVs is provided.Icing is a key
Hann, Richard, Johansen, Tor A.
Prevention of Snow Accretion on Camera Lenses of Autonomous Vehicles2020-01-01054/14/2020
With the rapid development of artificial intelligence, the autonomous vehicles (AV) have attracted considerable attention in the automotive industry. However, different factors negatively impact the adoption of the AVs, delaying their successful commercialization. Accretion of atmospheric icing, especially wet snow, on AV sensors causes blockage on their lenses, making them prone to lose their sight, in turn, increasing potential chances of accidents. In this study, two different designs are proposed in order to prevent snow accretion on the lenses of AVs via air flow across the lens surface. In both designs, lenses made of plain glass and superhydrophobic coated glass surfaces are tested. While some researchers have shown promise of water repellency on superhydrophobic surfaces, more snow accretion is observed on the superhydrophobic surfaces, when compared to the plain glass lenses. In the experiments, snow is formed using a novel snow gun inside a walk-in cold room connected to a
Mohammadian, Behrouz, Sarayloo, Mehdi, Heil, Jamie, Sojoudi, Hossein, Robertson, Michael, Hong, Haiping, Tran, Tommy, Patil, Sunil, Krishnan, Venkatesh
Application of Extended Messinger Models to Complex Geometries2020-01-00223/10/2020
Since, ice accretion can significantly degrade the performance and the stability of an airborne vehicle, it is imperative to be able to model it accurately. While ice accretion studies have been performed on airplane wings and helicopter blades in abundance, there are few that attempt to model the process on more complex geometries such as fuselages. This paper proposes a methodology that extends an existing in-house Extended Messinger solver to complex geometries by introducing the capability to work with unstructured grids and carry out spatial surface streamwise marching. For the work presented here commercial solvers such as STAR-CCM+ and ANSYS Fluent are used for the flow field and droplet dispersed phase computations. The ice accretion is carried out using an in-house icing solver called GT-ICE. The predictions by GT-ICE are compared to available experimental data, or to predictions by other solvers such as LEWICE and STAR-CCM+. Three different cases with varying levels of
Gupta, Avani, Sankar, Lakshmi, Kreeger, Richard
Sensor Uses Microwaves to Determine Real-Time Ice AccumulationTBMG-361953/1/2020
A sensor detects the precise moment when ice begins to form on a surface. Due to their high sensitivity, low power, ease of fabrication, and planar profile, microwave resonators were chosen for the device.
EquipmentAS6286/2A (Current)11/8/2019
This document covers the standards of de-icing/anti-icing equipment. In conjunction with the main document and other related slash sheets it will provide guidelines for the proper procedures to deice and anti-ice aircraft on the ground information to support this training program is provided to make the material a better tool for the preparation and execution of the training & qualification. It is intended to provide a common basis for de-icing/anti-icing training and qualification for de- icing providers and airlines. This material was compiled using various international documents with support from SAE documents and individually contributed editorial comments. Its purpose is to serve as a "Globalized Deicing Training Manual".
G-12T Training and Quality Programs Committee
Compensating the Effects of Ice Crystal Icing on the Engine Performance by Control Methods2019-01-18629/16/2019
Aircraft equipment is operated in a wide range of external conditions, which, with a certain combination of environmental parameters, can lead to icing of the engine internal elements. Due to icing, the engine components performance characteristics change what leads to decrease in thrust, gas dynamic stability, durability, etc. Safe aircraft operation and its desired performance may be lost as a result of such external influence. Therefore, it is relevant to study the possibilities of reducing the icing effect with the help of a special engine control. The focus of this paper is to determine control methods of an aircraft gas turbine engine addressing this problem. The object of the study is a modern commercial turbofan with a bypass ratio of about 9. In this paper analysis of the effect of ice crystal icing on the engine components performance is conducted. To perform simulation of the engine performance under such impact, degraded components characteristics was introduced into
Gurevich, Oskar, Smetanin, Sergei, Trifonov, Mikhail
Phase-Switching Liquids as Anti-Icing MaterialsTBMG-347557/1/2019
Techniques to prevent frost and ice formation on surfaces rely heavily on heating or on liquid chemicals that need to be repeatedly reapplied because they easily wash away. Even advanced anti-icing materials have problems functioning under conditions of high humidity and subzero conditions.
Numerical Investigation of the NASA Glenn Propulsion Systems Laboratory2019-01-19246/10/2019
NASA Glenn Research Center’s Propulsion Systems Laboratory (PSL) allows ice-crystal ice accretion tests on jet engines. This pressurized wind tunnel facility allows engines to be operated at flight altitudes and temperatures. Steady state and unsteady computational fluid dynamics simulations were performed for the PSL geometry, including the spray bars with their supports, and the converging duct section. These simulation results help to characterize the performance of the tunnel and are important for understanding the flow and particle behavior leading up to the engine test section. The results indicate complex flow structures, with vortex shedding and non-uniform flow features. Flow separation is observed in several regions. Several flow features and vortices are seen to persist to the duct exit plane where the fan section of a jet engine would be mounted for testing. Unsteady simulations show that periodic vortex shedding is created by the spray bars, and that the generated
Feier, Ioan
Experimental Study and Analysis of Ice Crystal Accretion on a Gas Turbine Compressor Stator Vane2019-01-19276/10/2019
A significant number of historical engine powerloss events have recently been attributed to ingestion of high altitude ice crystals, prompting regulators to expand engine certification envelopes to incorporate ‘ice crystal icing’ conditions. There has been a resulting effort by OEMs and academia to develop analytical and semi-empirical models for the phenomenon, partly through use of rig testing. The current study presents results and analysis of experiments conducted in the National Research Council’s Research Altitude Test Facility (RATFac). The experiments used a simplified compressor stator vane test article, designed to produce data to build semi-empirical models and validate an existing ice crystal icing code. Accretion growth rates, extracted from backlit shadowgraphy, are presented as a function of test condition, and the algorithm of a new image processing technique using Canny filtering is discussed. Wet bulb temperature, Mach number, particle size and test article angle of
Bucknell, Alexander, McGilvray, Matthew, Gillespie, David, Parker, Liam, Forsyth, Peter, Saad Ifti, Hassan, Jones, Geoffrey, Collier, Benjamin, Reed, Alasdair
Effect of Icing Environment and Humidity on Reference Air Data Parameters in an Icing Tunnel2019-01-19296/10/2019
Wind tunnel facilities typically rely upon reference instrumentation combined with isentropic flow relationships to define the fluid properties in the test section. For the particular case of icing wind tunnels, the icing environment can affect the airflow such that the definition of test section parameters via isentropic relationships is not strictly correct. These influences are of particular importance for testing air data probes because the nature of the test is to evaluate the performance of a sensor directly measuring the parameters being affected. Momentum, heat, and mass transfer from the water phase to the air phase can result in total temperature and total pressure measurements in the test section that differ from those measured at an upstream station, where reference measurements are typically taken. This effect was first observed by Luers & Fiscus [1] in the context of wind tunnel tests for heavy rain conditions.
Whalen, Mac, Matheis, Brian
A Smart Icing Detection System for Any Location on the Outer Aircraft Surface2019-01-19316/10/2019
Given approximately one million small and light aircraft in operation worldwide, icing detection and icing quantification of in-flight icing are still an open research topic. Despite technical means are available to de-ice on ground, there is a lack of a suitable control system based on sensor data to de-ice while the aircraft is airborne. Most often, it is still task of the pilot to visually inspect the icing status of the airfoil and/or other critical parts of the aircraft such as engine air intakes, which distracts the flight crew from flying the aircraft especially in IMC conditions. Based on preliminary simulation and tests in 2014 in a collaborative research project lasting from 2015 until 2018, the technology of energy self-sustaining, wireless, self-adhesive smart sensors for industrial sensing in an aerodynamically critical environment (i.e. wind turbines) was further investigated to fulfil general aviation requirements. Prototype hardware setups have been designed and built
Schlegl, Thomas, Moser, Michael, Loss, Theresa, Unger, Thomas
The Cloud Detectability Conundrum2019-01-19326/10/2019
Since the beginning of aviation, aircraft designers, researchers, and pilots have monitored the skies looking for clouds to determine when and where to fly as well as when to deice aircraft surfaces. Seeing a cloud has generally consisted of looking for a white / grey puffy orb floating in the sky, indicating the presence of moisture. A simple monitoring of a temperature gauge or dew point sensor was used to help determine if precipitation was likely or accumulation of ice / snow on the airframe could occur. Various instruments have been introduced over the years to identify the presence of clouds and characterize them for the purposes of air traffic control weather awareness, icing flight test measurements, and production aircraft ice detection. These instruments have included oil slides, illuminated rods, vibrating probes, hot wires, LIDAR, RADAR, and several other measurement techniques. Each technology has its own strength and weakness including the particle size range and water
Jackson, Darren Glenn
Experimental Processing of Methodical Questions of Modeling the Atmospheric Cloud Containing Ice Crystals and Mixed Phase2019-01-19226/10/2019
In Central Institute of Aviation Motors (Moscow, Russia) over the past few years, work has been carried out on upgrading the test cell to simulate the conditions of ice crystals and mixed phase in accordance with regulatory requirements. The key feature of this test cell is that it is a high-altitude climate test rig with the possibility of creating altitude conditions up to an altitude of 15 km, as well as creating a high-speed stream up to 0.85 Mach number and temperatures up to −40°С. The diameter of the wind tunnel of this test cell is 1.02 meters. The layout of the test rig includes a manifold for bringing ice crystals into the stream, as well as a water spray manifold. With the help of a water spray manifold, it is possible to produce supercooled droplets in the stream. Using two collectors at once gives opportunity to create a wide range of conditions for both ice crystals and mixed phase. Ice crystals are obtained by the method of mechanical crushing of an ice bar by a
Goriachev, Aleksei, Zhulin, Vadim, Goriachev, Pavel, Grebenkov, Sergei, Savenkov, Vladimir
Event-Driven Simulation of Particle-Particle and Particle-Surface Collisions in Ice Crystal Icing2019-01-20146/10/2019
This paper describes an event-driven simulation tool for predicting particle-particle and particle-surface interactions in ice crystal icing (ICI). A new accretion model which is much less empirical than existing models for predicting ICI accretion is also described. Unlike previous models, the new “gouge/bounce model” (GBM) differentiates between (erosion) losses resulting from particle bounce and those resulting from particle gouging. A bounce threshold based on the tangential Stokes number is used to calculate most of the bounce loss. The GBM also predicts ejecta velocities and directions, at least approximately, which is important because most of the mixed-phase mass flux impacting a surface actually bounces off or erodes existing material in ICI, thereby increasing the mass flux downstream. The event-driven simulation tool, denoted COLLIDE, has been applied to two test cases in which accretion growth appeared to be affected by TWC in a manner beyond that which would be expected
Currie, Thomas Charles
Extension of a 2D Algorithm for Catch Efficiency Calculation to Three Dimensions2019-01-20136/10/2019
Accurate calculation of the catch efficiency β is of paramount importance for any ice accretion calculation since β is the most important factor in determining the mass of ice accretion. A new scheme has been proposed recently in [1] for accurately calculating β on a discretized two-dimensional geometry based on the results of a Lagrangian droplet trajectory integrator (start and impact conditions). This paper proposes an extension to the algorithm in Ref. [1], which is applicable to three-dimensional surfaces with arbitrary surface discretization. The 3D algorithm maintains the positive attributes of the original 2D algorithm, namely mass conservation of the impinging water, capability to deal with overlapping impingement regions and with crossing trajectories, computational efficiency of the algorithm, and low number of trajectories required to reach good accuracy in catch efficiency. At the same time, the new 3D algorithm avoids typical difficulties of other approaches to determine
Bartels, Christian, Neubauer, Thomas, Hassler, Wolfgang
Electromechanical Resonant Ice Protection Systems: How to Favour Fractures Propagation2019-01-20326/10/2019
Many researches focus on piezoelectric ice protection systems with the objectives to develop light and low consumption resonant electromechanical systems for de-icing. These systems use the vibrations generated by piezoelectric actuators at resonance frequencies to produce shear stress at the interface between the ice and the support or to produce tensile stress in the ice. This article presents experimental results of de-icing tests performed with resonant piezoelectric systems that generate amplitudes of vibrations to exceed ice tensile strength or ice/support adhesive shear strength. The tests show that fractures are initiated but that the ice is not always completely detached. A methodology based on the energy release rate is presented to enable a better understanding of fractures initiation and propagation. The last section part of the article is dedicated to the study of a substrate made of a sandwich structure with a honeycomb panel in order to maximize fractures propagation
Rouset, Pierrick, Pommier-Budinger, Valérie, Budinger, Marc
Computational Simulation of an Electrically Heated Ice Protection System for Composite Leading Edges of Aircraft2019-01-20416/10/2019
The performance of an electrically heated aircraft ice protection system for a composite leading edge was evaluated. The composite leading edge of the model is equipped with a Ni alloy resistance heater. A state-of-the-art icing code, FENSAP-ICE, was used for the analysis of the electrothermal de-icing system. Computational results, including detailed information of conjugate heat transfer, were validated with experimental data. The computational model was then applied to the composite leading edge wing section at various metrological conditions selected from FAR Part 25 Appendix C.
Lawrence Raj, Prince Raj, Jeong, Hojin, Roy, Rene, Kweon, Jin-Hwe, Myong, Rho Shin
Quantification of 3D Ice Structures Accreted on a Wind Turbine Airfoil Model2019-01-20306/10/2019
Accurate quantification of 3D shapes of the complex ice structures accreted on wind turbine blades is highly desirable to develop ice prediction models for more accurate prediction of the aerodynamic performance degradation and power reduction due to the ice accretion on wind turbine blades. In the present study, an experimental investigation was conducted to quantitatively characterize the 3D shapes of the ice structures accreted over a DU91-W2-250 wind turbine airfoil model in the Icing Research Tunnel available at Iowa State University (ISU-IRT). A glaze icing condition and a rime icing condition that wind turbines usually experience in winter were duplicated by using ISU-IRT. A high-resolution non-intrusive 3D scanning system was used to make detailed 3D-shape measurements to quantify the complicated ice structures accreted on the wind turbine airfoil model as a function of the ice accretion time. The measurements results show that the complex 3D shapes of the ice structures
Gao, Linyue, Veerakumar, Ramsankar, Liu, Yang, Hu, Hui
Summary of the High Ice Water Content (HIWC) RADAR Flight Campaigns2019-01-20276/10/2019
NASA and the FAA conducted two flight campaigns to quantify onboard weather radar measurements with in-situ measurements of high concentrations of ice crystals found in deep convective storms. The ultimate goal of this research was to improve the understanding of high ice water content (HIWC) and develop onboard weather radar processing techniques to detect regions of HIWC ahead of an aircraft to enable tactical avoidance of the potentially hazardous conditions. Both HIWC RADAR campaigns utilized the NASA DC-8 Airborne Science Laboratory equipped with a Honeywell RDR-4000 weather radar and in-situ microphysical instruments to characterize the ice crystal clouds. The purpose of this paper is to summarize how these campaigns were conducted and highlight key results. The first campaign was conducted in August 2015 with a base of operations in Ft. Lauderdale, Florida. Ten research flights were made into deep convective systems that included Mesoscale Convective Systems (MCS) near the Gulf
Ratvasky, Thomas, Harrah, Steven, Strapp, J. Walter, Lilie, Lyle, Proctor, Fred, Strickland, Justin, Hunt, Patricia, Bedka, Kristopher, Diskin, Glenn, Nowak, John B., Bui, T. P., Bansemer, Aaron, Dumont, Christopher
Material Properties of Granular Ice Layers Characterized Using a Rigid-Body-Penetration Method: Experiments and Modeling2019-01-20346/10/2019
Accretion and shedding of ice layers is a serious problem for various engineering applications. In particular, ice layers growing due to ice crystal impingement on warm parts of an aircraft jet engine pose a severe hazard since they seriously affect safe operation of an aircraft. The material properties, and in the first place the strength of an ice layer, are crucial for the mechanisms leading to, and taking place during, both accretion and shedding of an ice layer. In the present study, the apparent yield strength of dry granular ice layers is examined employing a novel rigid-body-penetration approach. Dynamic projectile penetration into granular ice layers of varying porosity and ice grain size is experimentally investigated for different projectile impact velocities using a high-speed video system and post-processing of the captured video data. The obtained data for the total penetration depth of the projectile is used to calculate the apparent yield strength of the ice layer based
Schremb, Markus, Malicevic, Kenan, Reitter, Louis, Roisman, Ilia, Tropea, Cameron
An Experimental Study on the Effects of the Layout of DBD Plasma Actuators on Its Anti-/De-Icing Performance for Aircraft Icing Mitigation2019-01-20336/10/2019
Recently developed dielectric barrier discharge (DBD) plasma-based anti-icing systems have shown great potential for aircraft icing mitigation. In the present study, the ice accretion experiments were performed on to evaluate the effects of different layouts of DBD plasma actuators on their anti-/de-icing performances for aircraft icing mitigations. An array of DBD plasma actuators were designed and embedded on the surface of a NACA0012 airfoil/wing model in different layout configurations (i.e., different alignment directions of the plasm actuators (e.g., spanwise vs. streamwise), width of the exposed electrodes and the gap between the electrodes) for the experimental study. The experimental study was carried out in the Icing Research Tunnel available at Iowa State University (i.e., ISUIRT). While the dynamic anti-icing operation is recorded by using a high-resolution imaging system, a high-speed Infrared (IR) thermal imaging camera is used to quantitatively map the temperature
Kolbakir, Cem, Liu, Yang, Hu, Haiyang, Hu, Hui
Experimental Investigations of an Icing Protection System for UAVs2019-01-20386/10/2019
UAV icing is a severe challenge that has only recently shifted into the focus of research. Today, there are no mature icing mitigation technologies for UAVs, except for the largest fixed-wing drones. We are working on the development of an electro-thermal icing protection technology called D•ICE for medium-sized fixed-wing UAVs. As part of the design process, an experimental test campaign at the Cranfield icing wind tunnel has been conducted. This paper describes the icing protection system and shares experimental results on its capability for icing detection and anti-icing. Icing detection is based on an algorithm evaluating temperature signals that are induced on the leading-edge of the wing. A baseline signal is generated during dry (icing cloud off) conditions and compared to a signal during wet (icing cloud on) conditions. Due to significant differences in the heat transfer regime, the system can differentiate between these two states. The experiments show that our system can
Hann, Richard, Borup, Kasper, Zolich, Artur, Sorensen, Kim, Vestad, Håvard, Steinert, Martin, Johansen, Tor
Analysis of Experimental Ice Accretion Data and Assessment of a Thermodynamic Model during Ice Crystal Icing2019-01-20166/10/2019
This paper analyzes ice crystal icing accretion data and evaluates a thermodynamic ice crystal icing model, which has been previously presented, to describe the possible mechanisms of icing within the core of a turbofan jet engine. The model functions between two distinct ice accretions based on a surface energy balance: freeze-dominated icing and melt-dominated icing. Freeze-dominated icing occurs when liquid water (from melted ice crystals) freezes and accretes on a surface along with the existing ice of the impinging water and ice mass. This freeze-dominated icing is characterized as having strong adhesion to the surface. The amount of ice accretion is partially dictated by a freeze fraction, which is the fraction of impinging liquid water that freezes. Melt-dominated icing occurs as unmelted ice on a surface accumulates. This melt-dominated icing is characterized by weakly bonded surface adhesion. The amount of ice accumulation is partially dictated by a melt fraction, which is the
Bartkus, Tadas P., Tsao, Jen-Ching, Struk, Peter M.
Measured Interfacial Residual Strains Produced by In-Flight Ice2019-01-19986/10/2019
The formation of ice on aircraft is a highly dynamic process during which ice will expand and contract upon freezing and undergoing changes in temperature. Finite element analysis (FEA) simulations were performed investigating the stress/strain response of an idealized ice sample bonded to an acrylic substrate subjected to a uniform temperature change. The FEA predictions were used to guide the placement of strain gages on custom-built acrylic and aluminum specimens. Tee rosettes were placed in two configurations adjacent to thermocouple sensors. The specimens were then placed in icing conditions such that ice was grown on top of the specimen. It was hypothesized that the ice would expand on freezing and contract as the temperature of the interface returned to the equilibrium conditions. While results from the aluminum specimens matched this hypothesis, results from the acrylic specimens show a short period of contraction followed by a much larger expansion at the interface, indicating
Work, Andrew, Salem, Jonathan, Baker, Eric, Schirmer, Ernestina, Douglass, Rebekah, Kreeger, Richard
Total Temperature Measurements in Icing Cloud Flows Using a Rearward Facing Probe2019-01-19236/10/2019
This paper reports on temperature and humidity measurements from a series of ice-crystal icing tunnel experiments conducted in June 2018 at the Propulsion Systems Laboratory at the NASA Glenn Research Center. The tests were fundamental in nature and were aimed at investigating the icing processes on a two-dimensional NACA0012 airfoil subjected to artificially generated icing clouds. Prior to the tests on the airfoil, a suite of instruments, including total temperature and humidity probes, were used to characterize the thermodynamic flow and icing cloud conditions of the facility. Two different total temperature probes were used in these tests which included a custom designed rearward facing probe and a commercial self-heating total temperature probe. The rearward facing probe, the main total temperature probe, is being designed to reduce and mitigate the contaminating effects of icing and ingestion of ice crystals and water droplets at the probe’s inlet. The probe also serves as an air
Agui, Juan H., Struk, Peter, Bartkus, Tadas
Microwave Technique for Liquid Water Detection in Icing Applications2019-01-19306/10/2019
The partial melting of ingested ice crystals can lead to ice accretion in aircraft compressors, but accurately measuring the relatively small fraction of liquid water content in such flows is challenging. Probe-based methods for detecting liquid water content are not suitable for deployment within turbofan engines, and thus alternatives are sought. Recent research has described approaches based on passive microwave sensing. We present here an approach based on active microwave transmission and reflection, employing a vector network analyzer. Utilization of both transmission and reflection provides additional data over and above emission or transmission only, and permits a more controllable environment than passive sensing approaches. The paper specifically addresses the question of whether such an approach is viable within the context of representative icing wind tunnel and engine flow conditions. A quasi-thermal equilibrium approach is presented herein to estimate the melting ratio
Leis, John, Buttsworth, David, Saeed, Ramiz, Saleh, Khalid, McGilvray, Matthew, Gillespie, David
Non-Spherical Particle Trajectory Modelling for Ice Crystal Conditions2019-01-19616/10/2019
Aircraft icing is a significant issue for aviation safety. In this paper, recent developments for calculating the trajectory of non-spherical particles are used to determine the trajectory and impingement of ice crystals in aircraft icing scenarios. Two models are used, each formulated from direct numerical simulations, to give the drag, lift and torque correlations for various shaped particles. Previously, within the range of Reynolds number permitted in this study, it was only possible to model the trajectory and full rotational progression of cylindrical particles. The work presented in this paper allows for analysis of a wider range of ice shapes that are commonly seen in icing conditions, capturing the dynamics and behaviours specific to ice crystals. Previous limitations relate to the in ability to account for particle rotation and the dependency of force correlations on the measure of particle sphericity - which are now overcome. The method also provides an opportunity for new
Palmer, Ryan, Roberts, Ian, Moser, Richard, Hatch, Colin, Smith, Frank
A Study of Droplet Breakup in the Vicinity of an Airfoil2019-01-20006/10/2019
Supercooled large droplets can breakup before imping on aerodynamic surfaces and this should be taken into account in the icing codes. A study of droplets breakup in the vicinity of an airfoil has been conducted. Experiments for streams of droplets that were allowed to fall in the path of an incoming airfoil attached to a rotatory arm were conducted at the INTA facility. Droplets diameters ranged from 500 μm to 3 mm and two airfoils models of leading edge radius of 70 mm and 103 mm moving at velocities of 70 m/s, 80 m/s and 90 m/s were tested. Two subsets of experimental data for both bag and stamen breakup and shear breakup modes were used in this investigation. For these cases a numerical trajectory and deformation model was applied to obtain the evolution of the horizontal position, and the droplet maximum and minimum diameter. Breakup onset was determined from experimental data. Though previous works considered that breakup starts when there is a minimum in the minimum diameter
Sor, Suthyvann, Garcia-Magariño, Adelaida, Velazquez, Angel
Scaling Evaluation of Ice-Crystal Icing on a Modern Turbofan Engine in PSL Using the COMDES-MELT Code2019-01-19206/10/2019
This paper presents preliminary ice-crystal icing (ICI) altitude scaling evaluation results of a Honeywell Uncertified Research Engine (HURE) that was tested in the NASA Glenn Research Center Propulsion Systems Laboratory (PSL) during January of 2018. This engine geometry features a hidden core design to keep the core less exposed. The engine was fitted with internal video cameras to observe various ice buildup processes at multiple selected locations within the engine core flow path covering the fan stator, the splitter-lip/shroud/strut, and the high pressure compressor (HPC) variable inlet guide vane (IGV) regions. The potential ice accretion risk was pre-determined to occur by using NASA’s in-house 1D Engine Icing Risk assessment code, COMDES-MELT. The code was successful in predicting the risk of ice accretion in adiabatic regions like the fan-stator of the HURE at specific engine operating points. However at several operating points during the test, liquid water was observed
Tsao, Jen-Ching
Ice-Crystal Icing Accretion Studies at the NASA Propulsion Systems Laboratory2019-01-19216/10/2019
This paper describes an ice-crystal icing experiment conducted at the NASA Propulsion System Laboratory during June 2018. This test produced ice shape data on an airfoil for different test conditions similar to those inside the compressor region of a turbo-fan jet engine. Mixed-phase icing conditions were generated by partially freezing out a water spray using the relative humidity of flow as the primary parameter to control freeze-out. The paper presents the ice shape data and associated conditions which include pressure, velocity, temperature, humidity, total water content, melt ratio, and particle size distribution. The test featured a new instrument traversing system which allowed surveys of the flow and cloud. The purpose of this work was to provide experimental ice shape data and associated conditions to help develop and validate ice-crystal icing accretion models. The results support previous experimental observations of a minimum melt-ratio threshold for accretion to occur as
Struk, Peter M., Agui, Juan, Ratvasky, Thomas, King, Michael, Bartkus, Tadas, Tsao, Jen-Ching
Ranking of Thick Ice Shapes Based on Numerical Simulation for Certification2019-01-19446/10/2019
The objective of this paper is to present a numerical method to rank thick ice shapes for aircraft by comparing the ice accretion effects for different icing scenarios in order to determine the more critical ice shape. This ranking allows limiting the demonstration of the aerodynamic characteristics of the aircraft in iced condition during certification to a reduced number of ice shapes. The usage of this numerical method gives more flexibility to the determination of the critical ice shapes, as it is not dependent of the availability of physical test vehicles and/or facilities. The simulation strategy is built on the Lattice Boltzmann Method (LBM) and is validated based on a representative test case, both in terms of aircraft geometry and ice shapes. Validation against existing experimental results shows the method exhibits an adequate level of reliability for the ranking of thick ice shapes.
Barth, Marcus, Degrigny, Johan, Brown, James, Tezok, Fatih, Lewis, Richard, Alegre, Nathalie, Barrios-Garcia, Isaac
NRC Particle Detection Probe: Results and Analysis from Ground and Flight Tests2019-01-19336/10/2019
High altitude ice crystals are causing in-service events in excess of one per month for commercial aircraft. The effects include air data probes malfunctioning (pitot pressure and total air temperature in particular), and uncommanded engine power loss or flameout events. The National Research Council Canada (NRC) has developed a particle detection probe (PDP) that mounts on the fuselage of aircraft to sense and quantify the ice crystals in the environment. The probe is low-power and non-intrusive. This paper presents the results of ground and flight testing of this probe. Results are presented for ground testing in a sea level ice crystal wind tunnel and an altitude icing tunnel capable of generating both ice crystal and super-cooled liquid. The PDP was operated on several flight campaigns and the results of two will be presented. The first was on board a NRC Convair 580 aircraft in French Guiana (FG) and the second was on an Airbus operated A340 research aircraft in Darwin and Reunion
Davison, Craig, Chalmers, Jennifer, Fuleki, Dan
ICICLE: A Model for Glaciated & Mixed Phase Icing for Application to Aircraft Engines2019-01-19696/10/2019
High altitude ice crystals can pose a threat to aircraft engine compression and combustion systems. Cases of engine damage, surge and rollback have been recorded in recent years, believed due to ice crystals partially melting and accreting on static surfaces (stators, endwalls and ducting). The increased awareness and understanding of this phenomenon has resulted in the extension of icing certification requirements to include glaciated and mixed phase conditions. Developing semi-empirical models is a cost effective way of enabling certification, and providing simple design rules for next generation engines. A comprehensive ice crystal icing model is presented in this paper, the Ice Crystal Icing ComputationaL Environment (ICICLE). It is modular in design, comprising a baseline code consisting of an axisymmetric or 2D planar flowfield solution, Lagrangian particle tracking, air-particle heat transfer and phase change, and surface interactions (bouncing, fragmentation, sticking). In
Bucknell, Alexander, McGilvray, Matthew, Gillespie, David, Yang, Xin, Jones, Geoffrey, Collier, Benjamin
Evaluation of Visual Failure versus Aerodynamic Limit for a Snow Contaminated Anti-Iced Wing Section during Simulated Takeoff2019-01-19726/10/2019
Under contract to Airlines for America (A4A), APS Aviation Inc. (APS), in collaboration with the National Research Council of Canada (NRC), completed an aircraft ground icing exploratory research project at the NRC 3 m × 6 m Wind Tunnel in Ottawa in January 2019. The purpose of this project was to investigate the feasibility of using aerodynamic data to evaluate the performance of contaminated anti-icing fluid, rather than the traditional visual fluid failure indicators that are used to develop Holdover Times (HOTs). The aerodynamic performance of a supercritical airfoil model with anti-icing fluids and snow contamination was evaluated against the clean, dry performance of the airfoil in order to calculate the associated aerodynamic penalty. The visual failure of the fluid was also evaluated for each run, and the visual and aerodynamic results were compared against each other for each contamination exposure time. The results demonstrated that the visual failure of a fluid was not
Clark, Catherine, Ruggi, Marco
The Effect of Crosswinds on Icing at Turbofan Engine Inlet2019-01-20246/10/2019
Ice accretion at engine inlet has a dangerous effect on the inlet airflow and shed ice would be ingested into the engine and cause compressor blades damage, and even combustors flame out. In order to analyze the effect of crosswinds on icing at turbofan engine inlet, a complete icing analysis method, which is based on the Messinger model and takes the influence of runback water into consideration, is constructed. The runback water is considered laminar flow and the flow direction is dominated by the bottom flow of air. The supercooled water droplets impingement, ice accretion and runback water characteristics and inlet distortion with and without ice were investigated at crosswinds speed of 15, 20, 25, 30 kt. The variation of local water collection coefficient β is unchanged at crosswind conditions, but the location of the maximum value and non-dimensional impact limits change with the crosswind, which move backward along the outer edge on the windward, and move along the inner edge on
Yang, Qian, Guo, Zhiqiang, Zheng, Mei, Dong, Wei
Focus on Challenges in SLD Regime: Reemitted Droplet Modelling2019-01-20016/10/2019
A lot of studies have been carried out over the last decades on SLD ice accretion challenges. Many of them referred to SLD physics modelling such as break-up, splashing, bouncing, etc… and relied on numerous physics experiments. Different models have been developed in Europe and North-America and have been implemented in several numerical tools, widely in 2D but more and more in 3D. As these tools are intended to be used increasingly among the community, deficiencies have to be deeper investigated. This paper provides some highlights on specific needs linked to SLD impingement and ice accretion, especially for 3D high fidelity computations. Regarding the results, deficiencies on the numerical side and on experimental needs will be highlighted in order to feed brainstorming for ongoing SLD projects such as in European Union H2020 ICE-GENESIS.
Caminade, Francois, Frazza, Loïc
The Influence of SLD Drop Size Distributions on Ice Accretion in the NASA Icing Research Tunnel2019-01-20226/10/2019
An ice shape database has been created to document ice accretions on a 21-inch chord NACA0012 model and a 72-inch chord NACA 23012 airfoil model resulting from an exposure to a Supercooled Large Drop (SLD) icing cloud with a bimodal drop size distribution. The ice shapes created were documented with photographs, laser scanned surface measurements over a section of the model span, and measurement of the ice mass over the same section of each accretion. The icing conditions used in the test matrix were based upon previously used conditions on the same models but with an alternate approach to evaluation of drop distribution effects. Ice shapes resulting from the bimodal distribution as well as from equivalent monomodal drop size distributions were obtained and compared. Results indicate that the ice shapes resulting from the monomodal and bimodal drop size distributions had similar shapes, but the bimodal distributions had greater mass and volume measurements and icing limits that
Potapczuk, Mark G., Tsao, Jen-Ching
Numerical Modelling of Primary and Secondary Effects of SLD Impingement2019-01-20026/10/2019
A CFD simulation methodology for the inclusion of the post-impact trajectories of splashing/bouncing Supercooled Large Droplets (SLDs) and film detachment is introduced and validated. Several scenarios are tested to demonstrate how different parameters affect the simulations. Including re-injecting droplet flows due to splashing/bouncing and film detachment has a significant effect on the accuracy of the validations shown in the article. Validation results demonstrate very good agreement with the experimental data. This approach is then applied to a full-scale twin-engine turboprop to compute water impingement on the wings and the empennage. Since the performance characteristics of twin-engine commercial turboprops are such that they operate most efficiently at flight levels where SLD encounters may occur, the goal of this article is to establish a 3D computational methodology to eventually enable a complete study of the impact of FAR 25 Appendix O on the IPS requirements for this
Fouladi, Habibollah, Baruzzi, Guido S., Nilamdeen, Shezad, Ozcer, Isik
Utilization of Single Cantilever Beam Test for Characterization of Ice Adhesion2019-01-19496/10/2019
Many engineering systems operating in a cold environment are challenged by ice accretion, which unfavorably affects their aerodynamics and degrades both their performance and safety. Precise characterization of ice adhesion is crucial for an effective design of ice protection system. In this paper, a fracture mechanics-based approach incorporating single cantilever beam test is used to characterize the near mode-I interfacial adhesion of a typical ice/aluminum interface with different surface roughness. In this asymmetric beam test, a thin layer of ice is formed between a fixed and elastically deformable beam subjected to the applied loading. The measurements showed a range of the interfacial adhesion energy (GIC) between 0.11 and 1.34 J/m 2, depending on the substrate surface roughness. The detailed inspection of the interfacial ice fracture surface, using fracture surface replication technique, revealed a fracture mode transition with the measured macroscopic fracture toughness. The
Dawood, Bishoy, Yavas, Denizhan, Giuffre, Christopher, Bastawros, Ashraf
Numerical Simulation of Aircraft and Variable-Pitch Propeller Icing with Explicit Coupling2019-01-19546/10/2019
A 3D CFD methodology is presented to simulate ice build-up on propeller blades exposed to known icing conditions in flight, with automatic blade pitch variation at constant RPM to maintain the desired thrust. One blade of a six-blade propeller and a 70-passenger twin-engine turboprop are analyzed as stand-alone components in a multi-shot quasi-steady icing simulation. The thrust that must be generated by the propellers is obtained from the drag computed on the aircraft. The flight conditions are typical for a 70-passenger twin-engine turboprop in a holding pattern in Appendix C icing conditions: 190 kts at an altitude of 6,000 ft. The rotation rate remains constant at 850 rpm, a typical operating condition for this flight envelope. Two icing conditions are simulated: air static temperature -23 °C, LWC 0.2 g/m3 and MVD 20 microns resulting in rime ice, and air static temperature -16 °C, LWC 0.3 g/m3 and MVD 20 microns resulting in mixed ice with rime to glaze transition in the radial
Ozcer, Isik, Baruzzi, Guido S., Desai, Miraj, Yassin, Maged
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