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2015-06-15
Technical Paper
2015-01-2131
Colin Bidwell, David Rigby
A flow and ice particle trajectory analysis was performed for the booster of the Honeywell ALF502 engine. The analysis focused on two closely related conditions one of which produced an icing event and another which did not during testing of the ALF502 engine in the Propulsion Systems Lab (PSL) at NASA Glenn Research Center. The PSL tests subjected the engine to a High Ice Water Content (HIWC) environment. The flow analysis was generated using the NASA Glenn GlennHT flow solver and the particle analysis was generated using the NASA Glenn LEWICE3D v3.56 ice accretion software. The flow and particle analysis used a 3D steady flow, mixing plane approach to model the transport of flow and particles through the engine. The inflow conditions for the condition producing the icing event were: airspeed, 145 m/s; static pressure, 33,373 Pa; static temperature, 253.3 K.
2015-06-15
Technical Paper
2015-01-2130
Melissa Bravin, J. Walter Strapp, Jeanne Mason
In response to the occurrence of jet engine powerloss and damage events associated with deep convective clouds containing high concentrations of ice crystals, several research efforts are underway. Several flight measurement programs devoted to the collection of in-situ and remote sensing of clouds have been conducted over the past few years. The most recent in Darwin, Australia, from January-March 2014, and its follow-up planned for Cayenne, French Guiana, in May 2015, involve the use of a highly instrumented research aircraft with instrumentation specially designed to make accurate in-situ total water content (TWC) and median mass diameter (MMD) measurements of the high concentration areas of deep convection. The data will be used for atmospheric research related to understanding the microphysics of deep convection, and improving the ability to predict, detect and avoid these clouds.
2015-06-15
Technical Paper
2015-01-2094
William B. Wright, Peter Struk, Tadas Bartkus, Gene Addy
This paper will describe two recent modifications to the GlennICE software. First, a capability for modeling ice crystals and mixed phase icing has been modified based on recent experimental data. Modifications have been made to the ice particle bouncing and erosion model. This capability has been added as part of a larger effort to model ice crystal ingestion in aircraft engines. Comparisons have been made to ice crystal ice accretions performed in the NRC Research Altitude Test Facility (RATFac). Second, modifications were made to the runback model based on data and observations from thermal scaling tests performed in the NRC Altitude Icing Tunnel. Introduction Mason[1] describes a situation where an aircraft engine can encounter rollbacks and flameouts at high altitude conditions due to ice crystal ingestion. Numerous in-fight encounters had been observed. It was hypothesized that the cause of the incidents was the ingestion of a high volume of ice crystals into the engine.
2015-06-15
Technical Paper
2015-01-2078
Alric Rothmayer, Hui Hu
A strong air/water interaction theory is used to develop a fast simplified model for the trapping of water in a film that flows over sub-grid surface roughness. The sub-grid model is used to compute correction factors that can alter mass transport within the film. This sub-grid model is integrated into a covariant film mass transport model for film flow past three-dimensional surfaces of a form suitable for aircraft icing codes. Sample calculations are presented to illustrate the application of the model. Aircraft icing codes usually consist of an aerodynamic solver, a droplet trajectory solver and a mechanism to grow the ice surface. Recently, icing codes have also made use of simple models for surface water transport, typically through a film lubrication model.
2015-06-15
Technical Paper
2015-01-2088
Richard E. Kreeger, Lakshmi Sankar, Robert Narducci, Robert Kunz
The formation of ice over lifting surfaces can affect aerodynamic performance. In the case of helicopters, this loss in lift and the increase in sectional drag forces will have a dramatic effect on vehicle performance. The ability to predict ice accumulation and the resulting degradation in rotor performance is essential to determine the limitations of rotorcraft in icing encounters. The consequences of underestimating performance degradation can be serious and so it is important to produce accurate predictions, particularly for severe icing conditions. The simulation of rotorcraft ice accretion is a challenging multidisciplinary problem that until recently has lagged in development over its counterparts in the fixed wing community. But now, several approaches for the robust coupling of a computational fluid dynamics code, a rotorcraft structural dynamics code and an ice accretion code have been demonstrated.
2015-06-15
Technical Paper
2015-01-2079
Colin Hatch, Jason Moller, Eleftherios Kalochristianakis, Ian Roberts
Summary The size and shed time of ice shed from a propeller is predicted using a process that determines ice shape, ice growth rate and both internal and ice-structure interface stresses. A brittle failure damage model is used to predict the onset of local failure and to propagate damage in the ice until local ice shedding is obtained. Background Research into suitable ice-phobic coatings as a potential approach in an integrated aircraft ice protection system (IPS) has been ongoing for many years. Durability of these coatings has been an issue; however future research programmes such as the EU programmes AEROMUCO [1] and STORM [2] are looking to improve the Technology Readiness Level (TRL) of the application of these types of coatings. The introduction of ice-phobic coatings may make it possible to provide ice protection on rotating surfaces without the need for specialist ice protection systems.
2015-06-15
Technical Paper
2015-01-2116
Peter Struk, Tadas Bartkus, Jen-Ching Tsao, Tom Currie, Dan Fuleki
This paper describes ice accretion measurements from experiments conducted at the National Research Council (NRC) of Canada’s Research Altitude Test Facility during 2012. Due to numerous engine power-loss events associated with high-altitude convective weather, potential ice accretion within an engine due to ice-crystal ingestion is being investigated collaboratively by NASA and NRC. These investigations examine the physical mechanisms of ice accretion on surfaces exposed to ice-crystal and mixed-phase conditions, similar to those believed to exist in core compressor regions of jet engines. A further objective of these tests is to examine scaling effects since altitude appears to play a key role in this icing process. While the 2012 experiments had multiple objectives such as cloud characterization and the evaluation of imaging techniques, several tests were dedicated to observe ice accretions using both a NACA 0012 and a wedge-shaped airfoil.
2015-06-15
Technical Paper
2015-01-2155
Tadas P. Bartkus, Peter Struk, Jen-Ching Tsao
This paper describes a numerical model that simulates the thermal interaction between ice particles, water droplets, and the flowing air applicable during icing wind tunnel tests where there is significant phase-change of the cloud. The model is compared to measurements taken during wind tunnel tests simulating ice-crystal and mixed-phase icing that relate to ice accretions within turbofan engines. This model, written in MATLAB, is based on fundamental conservation laws and empirical correlations. Due to numerous power-loss events in aircraft engines, potential ice accretion within the engine due to the ingestion of ice crystals is being investigated. To better understand this phenomenon and determining the physical mechanism of engine ice accretion, fundamental tests have been collaboratively conducted by NASA Glenn Research Center and the National Research Council of Canada (NRC).
2015-06-15
Technical Paper
2015-01-2115
Antonio Criscione, Suad Jakirlic, Zeljko Tukovic, Ilia Roisman, Cameron Tropea
Atmospheric icing occurs when supercooled large drops (SLD) of water come in contact with the surface of exposed structures. Excessive accumulation on structures and equipment is well known for causing serious problems in cold-climate regions which lead to material damage and high costs in various sectors of the economy. Hereby, SLD impact with the exposed structure results consequently in an ice layer growth covering the surface of the substrate. The present study enables, among other things, modeling of both stages of the solidification process of a supercooled large water drop on a cold substrate - the first rapid, recalescent stage and the second slower, quasi-isothermal stage. The different mechanisms underlying both freezing stages can be explained as follows: in the first stage the initial planar solidification front becomes morphologically unstable due to a high degree of supercooling. Small bumps/instabilities evolving at the interface propagate further into the liquid.
2015-06-15
Technical Paper
2015-01-2121
Yong Chen, Liang Fu
In helicopter, the icing rotor blades will decrease the effectiveness of the helicopter and endanger the lives of the pilots. The asymmetrical ice break-up and shedding could also lead to severe vibrations of the rotor blade. Ice break-up from the main rotor may strike the fuselage and tail rotor, even worse, find its way into the engine, which may cause serious aircraft accidents. An understanding of the mechanisms responsible for ice shedding process is necessary in order to optimize the helicopter rotor blade design and de-icing system to avoid hazardous ice shedding. In previous study, the ice shedding criteria was established by comparing the centrifugal force and the adhesion force. In most cases, part of the ice will shed before the centrifugal force equals to the adhesion force, because the adhesion stress between the ice and the blade is not uniform.
2015-06-15
Technical Paper
2015-01-2102
Guilin Lei, Wei Dong, Jianjun Zhu, Mei Zheng
The numerical simulation of ice melting process on an iced helicopter rotor blade is presented. The ice melting model uses an enthalpy-porosity formulation, and treats the liquid-solid mushy zone as a porous zone with porosity equal to the liquid fraction. The ice shape on the blade section is obtained by the icing code with a dynamic mesh module. Both of the temperature change and the ice-melting process on the rotor blade section surface are analyzed. The phenomenon of ice melting is analyzed through the change of temperature and liquid fraction on the abrasion/ice interface. The liquid fraction change as with time on the abrasion/ice surface is observed, which describes the ice-melting process well. The numerical results show that the ice melting process can be simulated effectively by the melting model. The de-icing process can be monitored by observing the change of the liquid fraction of the area around the abrasion/ice interface.
2015-06-15
Technical Paper
2015-01-2141
Markus Widhalm
This paper focuses on the numerical simulation of the motion of regular shaped ice particles and the computation of aerodynamic forces and torques on such particles. The shape of an ice crystal may deviate considerably from a sphere and can occur as thin needles or disk-shaped configurations, referred as regular non-spherical particles, or in irregular form as flakes or agglomerates. Ice crystals can be found at the upper boundary of the troposphere in anvils of cumulonimbus clouds, where strong winds exist and an altitude, where jet aircraft cruise at transonic speed, imposing a high flow Reynolds number. As the particle size grows from a few microns into several 100's of microns a high particle Reynolds number may be expected too.
2015-06-15
Technical Paper
2015-01-2156
Michael Oliver
The National Aeronautics and Space Administration conducted a full scale ice crystal icing turbofan engine test in the NASA Glenn Research Center’s Propulsion Systems Laboratory (PSL) Facility in February 2013. Honeywell Engines supplied the test article, an obsolete, unmodified Lycoming ALF502-R5 turbofan engine serial number LF01 that experienced an uncommanded loss of thrust event while operating at certain high altitude ice crystal icing conditions. These known conditions were duplicated in PSL for this testing. The data generated during this testing contained three subsets: known event conditions, altitude scaling conditions and a design of experiment (DOE) data set. The key roll back indicating parameter was found to be the reduction of the measured load parameter, the average of two measured load cells mounted on the thrust stand.
2015-06-15
Technical Paper
2015-01-2107
Tom Currie, Dan Fuleki, Craig Davison
There is significant recent evidence that ice crystals ingested by a jet engine at high altitude can partially melt and then accrete within the forward stages of the compressor, potentially producing a loss of performance, rollback, combustor flameout, compressor damage, etc. Several studies of this ice crystal icing (ICI) phenomenon have been conducted in the past 5 years using the RATFac (Research Altitude Test Facility) altitude chamber at the National Research Council of Canada (NRCC), which includes an icing wind tunnel capable at operating at Mach numbers (M), total pressures (po) and temperatures (To) pertinent to ICI. Humidity can also be controlled and ice particles are generated with a grinder. The ice particles are entrained in a jet of sub-freezing air blowing into the tunnel inlet. Warm air from the altitude cell also enters the tunnel, where it mixes with the cold ice-laden jet, increasing the wet-bulb temperature (Twb) and inducing particle melting.
2015-06-15
Technical Paper
2015-01-2099
Mario Vargas, Charles Ruggeri, Peter Struk, Mike Pereira, Duane Revilock, Richard Kreeger
Ice Particle Impacts on a Flat Plate Mario Vargas, Peter M. Struk, Richard E. Kreeger, Charles Ruggeri, Mike Pereira, Duane Revilock National Aeronautics and Space Administration Glenn Research Center An experimental study was conducted at the Ballistic Laboratory of NASA Glenn Research Center to study the impact of ice particles on a stationary flat surface target set at 45 degrees with respect to the direction of motion of the impinging particle (Figure 1). The experiment is part of NASA efforts to study the physics involved in engine power-loss events due to ice-crystal ingestion and ice accretion formation inside engines. These events can occur when aircraft encounter high-altitude convective weather. The experiment was conducted to gain understanding of the physics involved when ice particles impact on a flat surface. Previous studies conducted by industry in the 1990s on the ingestion of ice particles in turbine engines were for hailstones.
2015-06-15
Technical Paper
2015-01-2125
Dan Fuleki, Jennifer L.Y. Chalmers, Brian Galeote
Ice crystal size has been shown to have a significant impact on the ice accretion phenomenon and is therefore a key variable to control and measure in a test environment. Traditional techniques and equipment used to measure particle size and morphology in the atmosphere are not easily utilized in an icing wind tunnel and in many cases, have poor performance with irregular shaped, solid, non-transparent particles. To overcome these limitations, a high magnification, non-intrusive shadowgraphy technique has been implemented at the National Research Council of Canada to measure airborne water droplet or ice particle size distributions. This system is based on a LaVision ParticleMaster platform which produces diffused laser light of uniform intensity, pulsed into a high resolution camera through a long distance microscope lens. The short duration pulses (9 ns) can produce sharp images of fast moving particles.
2015-06-15
Technical Paper
2015-01-2161
Kazem Hasanzadeh, Dorian Pena, Yannick Hoarau, Eric Laurendeau
The paper will present the framework of fully automated two/three dimensional ice accretion simulation package NSMB3D-ICE, with emphasis on the remeshing step. The NSMB3D-ICE Navier-Stokes code, coupled to an Eulerian droplet module and iterative Messinger thermodynamic model, can perform multi time-steps ice accretion simulations via an automated multi-block elliptic/parabolic grid generation code (NSGRID3D). Attention is paid to the efficiency and robustness of the numerical procedure especially for complex 3D glaze ice simulation. The new automated multi time-step icing code NSMB3D-ICE/NSGRID3D is validated and verified using several icing case studies such as the GLC305-3D rime and glaze ice cases. The Navier-Stokes flow solver NSMB3D is a finite volume three-dimensional multi-block Euler/Navier-Stokes flow solver developed by J. Vos et al. [1-3].
2015-06-15
Technical Paper
2015-01-2119
Shinan Chang, Chao Wang, Mengyao Leng
Drop deformation and breakup is an important issue that involved in the aircraft and engine icing field especially in the case of the supercooled large droplets (SLD). In this paper, the breakup modes of SLD are discussed in detail based upon the classical theories of the drop breakup and typical icing conditions. It is found that the breakup modes of SLD are mainly vibration breakup, bag-type breakup, multimode breakup and shear breakup. As the vibration breakup mode is rare, focuses are put on the bag-type breakup, multimode breakup and shear breakup. Because the drop Weber number is increasing gradually when the drops are approaching the leading edge of the airfoil and the drop Weber number differs in different locations of the airfoil surface, two or three breakup modes may appear simultaneously in a given environmental condition.
2015-06-15
Technical Paper
2015-01-2118
Sergey Alekseyenko, Michael Sinapius, Martin Schulz, Oleksandr Prykhodko
In spite of wide theoretical and experimental studies of icing problem that have been held up to recent times, nevertheless, the most dangerous flights regimes as in the presence of supercooled large droplets or in supercooled rain remain studied not enough. Also the range of parameters that corresponds to the exploitation modes of aircrafts with relatively small heights and speeds of flight like airplanes of small aviation, helicopters, UAV etc. because of the complexity of the icing processes are still not covered. The aim of this work is to answer the next question: which an actual process of interaction of supercooled large water droplets with growing ice surface at small speeds of flight and which physics of falling moisture freezing process on the icing surface is. Thus, the work presents the results of experiments conducted in order to obtain the photographic data on how the interaction between the supercooled water droplets and the icing aerodynamic surface occurs.
2015-06-15
Technical Paper
2015-01-2087
Delphine Leroy, Emmanuel Fontaine, Alfons Schwarzenboeck, J. Walter Strapp, Lyle Lilie, Julien Delanoe, Alain Protat, Fabien Dezitter, Alice Grandin
Title: HAIC/HIWC field campaign - specific findings on PSD microphysics in high IWC regions from in situ measurements: crystal size distribution characteristics, ice density, and median mass diameters Authors: Delphine Leroy (CNRS-LaMP), Emmanuel Fontaine (CNRS-LaMP), Alfons Schwarzenboeck (CNRS-LaMP), J.
2015-06-15
Technical Paper
2015-01-2093
Maxime Henno
A numerical tool has been developed for predicting the unsteady behavior of the thermal wing ice protection systems (WIPS). The code was developed to account for a multi-layer composite structure. The performance predictions of a WIPS integrated into a metallic or into a composite structure can thus be achieved. The tool enables the simulation of unsteady anti-icing operations, for example, the WIPS may be activated with delay after entering into the icing conditions. In this case, ice starts to accrete on the leading edge before the WIPS heats up the skin. Another example is the ground activation of the WIPS for several seconds to check its functionality: low external cooling may cause high thermal constraints that must be estimated with accuracy to avoid adverse effects on the structure. The simulations give further opportunities compared to the current practice.
2015-06-15
Technical Paper
2015-01-2143
Christian Mendig
In the project SuLaDI (Super Large Droplet Icing) research about the icing of airfoils through super large and super cooled droplets is done at the Institute of Composite Structures and Adaptive Systems (German Aerospace Center) and at the institute of Adaptronics and Function Integration (Technische Universität Braunschweig). In the framework of the project a deicing facility was built. It consists of a cooling chamber and a wind tunnel of the Eiffel-type therein. The icing of specimen takes place in the test chamber of the wind tunnel at temperatures below 0 °C. Between the flow straightener and the contraction section a spray system is built in, which sprays water droplets into the wind tunnel. The droplets are accelerated by the airstream and supercool on the way to the specimen. That means they cool down below the freezing point temperature, but they stay fluid. When hitting the specimen they freeze on it to rime ice, clear ice or mixed ice.
2015-06-15
Technical Paper
2015-01-2106
Mark Ray, Kaare Anderson
Cloud phase discrimination, with measurements of liquid water content (LWC) and ice water content (IWC) as well as the detection and discrimination of supercooled large droplets (SLD), are of primary importance due to several high-profile incidents over the past two decades. The UTC Aerospace Systems Optical Ice Detector (OID) is a prototype laser sensor intended to discriminate cloud phase, to quantify LWC and IWC, and to detect SLD and differentiate SLD conditions from Appendix C conditions. Phase discrimination is achieved through depolarization scattering measurements of a circularly polarized laser beam transmitted into the cloud. Optical extinction measurements indicate the liquid and ice water contents, while the differential backscatter from two distinct probe laser wavelengths infers an effective droplet size. The OID is designed to be flush-mounted with the aircraft skin and to sample the air stream beyond the boundary layer of the aircraft.
2015-05-20
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2015-04-14
Technical Paper
2015-01-0926
Tianyun Li, Min Xu, David Hung, Shengqi Wu, Siqi Cheng
Abstract Comparing with port-fuel-injection (PFI) engine, the fuel sprays in spark-ignition direct-injection (SIDI) engines play more important roles since they significantly influence the combustion stability, engine efficiency as well as emission formations. In order to design higher efficiency and cleaner engines, further research is needed to understand and optimize the fuel spray atomization and vaporization. This paper investigates the atomization and evaporation of n-pentane, gasoline and surrogate fuels sprays under realistic SIDI engine conditions. An optical diagnostic technique combining high-speed Mie scattering and Schlieren imaging has been applied to study the characteristics of liquid and vapor phases inside a constant volume chamber under various operating conditions. The effects of ambient temperature, fuel temperature, and fuel type on spray atomization and vaporization are analyzed by quantitative comparisons of spray characteristics.
2015-04-14
Technical Paper
2015-01-0494
Sulki Seong, Wangoo Kim, Daesung Bae, Seungpyo Lee, Younggeol Cho, Kyeongdeok Yang
Bearing is an important part for supporting the weight and transmits power. Rotating bearing is required excellent durability. Various studies have been conducted long time, for predict performance and durability of the bearing. However, prediction of the bearing durability has been used expression computation method using a theoretical formula between the raceway and ball. Flange analysis is commonly used structural analysis. Such an approach, have assumed to be static load. So it is difficult to consider the dynamic characteristics (Centrifugal force, Gyroscope effect) of the bearing. In order to predict the accurate bearing endurance life, it should be considering the dynamic characteristics. This paper proposes the method for bearing endurance life prediction considering dynamic characteristic. Between the raceway and ball contact is one of the important factors to take into account the dynamic characteristics of the bearing.
2015-04-14
Technical Paper
2015-01-0204
Biswajit Panja, Lars Wolleschensky
Abstract In this paper we propose a secure wireless sensor network system for vehicle health monitoring (VHM). We discuss the architecture of the proposed model, and it's implementation in vehicles. Modified AES-CCM is used to provide confidentiality in the network. In the proposed scheme combination of interactive and non-interactive methods are used for reliable message delivery.
2015-04-14
Technical Paper
2015-01-0267
Ryoichi Inada, Teppei Hirotsu, Yasushi Morita, Takahiro Hata
Abstract The ISO 26262 is a functional safety standard for road vehicles. The standard requires manufacturers to conduct quantitative assessment of the diagnostic coverage (DC) of products. The DC is defined as the percentage of failure probability covered by safety mechanisms. However, DC evaluation methods for drift faults, in which the change in element values is not constant, have not been discussed. In this paper, we propose a DC evaluation method for analog circuits with drift faults. With this method, we first parameterize the effect of drift faults onto a bounded region then split the region into safe fault, hazardous detectable fault, and hazardous undetectable fault regions. We evaluate the classification rate distribution by the area ratios of these regions.
2015-04-14
Technical Paper
2015-01-0439
Daniel B. Kosinski
Abstract The current reliability growth planning model used by the US Army, the Planning Model for Projection Methodology (PM2), is insufficient for the needs of the Army. This paper will detail the limitations of PM2 that cause Army programs to develop reliability growth plans that incorporate unrealistic assumptions and often demand that infeasible levels of reliability be achieved. In addition to this, another reliability growth planning model being developed to address some of these limitations, the Bayesian Continuous Planning Model (BCPM), will be discussed along with its own limitations. This paper will also cover a third reliability growth planning model that is being developed which incorporates the advantageous features of PM2 and BCPM but replaces the unrealistic assumptions with more realistic and customizable ones.
2015-04-14
Technical Paper
2015-01-1405
Guanjun Zhang, Feng Yu, Zhigao OuYang, Huiqin Chen, Zhonghao Bai, Libo Cao
Abstract The combination of passive and active vehicle safety technologies can effectively improve vehicle safety. Most of them predict vehicle crashes using radar or video, but they can't be applied extensively currently due to the high cost. Another collision forecasting method is more economic which is based on the driver behavior and vehicle status, such as the acceleration, angular velocity of the brake pedal and so on. However, the acceleration and angular velocity of the brake pedal will change with the driver and the vehicle type. In order to study the effect of different drivers and vehicle types on the braking acceleration and angular velocity of the brake pedal, six volunteers were asked to drive five vehicles for simulating the working conditions of emergency braking, normal braking, inching braking and passing barricades under different velocities. All the tests were conducted on asphalt road, and comprehensive experimental design was used to arrange tests.
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