Browse Topic: Water

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PWI and DWI Systems in Modern GDI Engines: Optimization and Comparison Part I: Non-Reacting Flow Analysis2021-01-046104/06/2021
Currently engine designers are focusing their attention on the improvement of the engine efficiency, led by the reduction of in-cylinder temperature and the adoption of stoichiometric combustion in the full range of the engine operation map. The most demanding points are those close to full power: water injection is thought to help in fulfilling this goal, thus contributing towards more efficient engines. To perform a rapid optimization of the main parameters involved by the water injection process, it is necessary to have reliable CFD methodologies capable of capturing the most important phenomena. In the present work, a methodological approach based on the CFD simulation of non-reacting flows of S.I. GDI turbocharged engines under water injection operation is pursued using AVL Fire code v. 2020. Port Water Injection (PWI) and Direct Water Injection (DWI) have been tested for the same baseline engine configuration and they have been run at full power condition, at the same rated power
Falfari, Stefania, Cazzoli, Giulio, Ricci, Matteo, Forte, Claudio
Investigating the Effect of Water and Oxygen Distributions on Consistency of Current Density Using a Quasi-Three-Dimensional Model of a PEM Fuel Cell2021-01-073704/06/2021
Activation loss, mass transfer loss and ohmic loss are the three main voltage losses of the polymer electrolyte membrane fuel cell. While the former two types are relevant to concentration of oxygen in catalyst layer and the later one is associated with the water content in membrane. Distributions of water content and oxygen in a single cell are inconsistent which cause that current densities in each segment of the single cell are different. For the dry inlet gas, the water in the segments near the gas inlet channel will be carried to the segments near the gas outlet channel, which causes high ohmic loss of the segments near the gas inlet channel. In this work, a transfer non-isothermal quasi-three-dimensional model is developed to investigate inconsistency of current densities. Comprehensive physical and chemical phenomena inside the cell are included, especially the mass transfer of hydrogen, oxygen, vapor and liquid water in gas channels, gas diffusion layer and catalyst layer and
Wang, Xuhui, Lu, Yikang, Zhang, Baitao, Xu, Sichuan
PWI and DWI Systems in Modern GDI Engines: Optimization and Comparison Part II: Reacting Flow Analysis2021-01-045404/06/2021
The water injection is one of the recognized technologies capable of helping the future engines to work at full load conditions with stoichiometric mixture. In the present work, a methodology for the CFD simulation of reacting flow conditions using AVL Fire code v. 2020 is applied for the assessment of the water injection effect on modern GDI engines. Both Port Water Injection and Direct Water Injection have been tested for the same baseline engine configuration under reacting flow conditions. The ECFM-3Z model adopted for combustion and knock simulations have been performed by adopting correlations for laminar flame speed, flame thickness and ignition delay times prediction, to consider the modified chemical behavior of the mixture due to the added water vapor. This improved methodological approach allows considering both the fluid-dynamics aspects (in terms of turbulence level close to ignition time and average in the combustion chamber), the mixture quality and the chemical
Falfari, Stefania, Bianchi, Gian Marco, Pulga, Leonardo, Forte, Claudio
Comparison of Partial and Total Dilution Systems for the Measurement of Polycyclic Aromatic Hydrocarbons and Hydrocarbon Speciation in Diesel Exhaust2020-01-219009/15/2020
Two methods of sampling exhaust emissions are typically used for characterizing emissions from diesel engines: total dilution which uses a constant volume sampling (CVS) system and partial flow dilution which relies on proportionally diluting a small part from the main exhaust stream. The CVS dilutes the entire exhaust flow to a constant volumetric flowrate which allows for proportional sampling of the exhaust species during transient engine operation. For partial dilution sampling during transient engine operation, obtaining a proportional sample is more rigorous and dilution of the extracted sample must be continuously changed throughout the cycle in order for the extracted sample flowrate to be proportional to the continuously changing exhaust flow. Typically, regulated emissions measured using both methods for an engine platform have shown good correlation. The focus for this work was on the experimental investigation of the two methods for the measurement of unregulated species. A
Fanick, E. Robert, Premnath, Vinay
Synthesis of Fuel Systems Boron-Containing Metalized Fuels for Vehicles2020-01-215509/15/2020
Ensuring the highest efficiency and power trains performance of vehicles remains the most important function of their creators. It is currently difficult to deny the fact that there are limited hydrocarbon reserves for fuel production, and these reserves are constantly decreasing. In addition, the specific energy intensity of hydrocarbon fuel is insufficient for the effective operation of power trains of transport for different invironments such as outer space or inert atmosphere. Intensive development of promising kind of transport caused by the complexity of human activities and the need for simultaneous movement in various alternating environments (movement on land, in water, in airless space). To solve this problem, it is proposed to search for substitutes for hydrocarbon fuels. We have investigated the possibilities of using boron-containing metallized fuels. Boron-containing fuel was used as the main fuel. The optimal concentration of boron and the most effective metallized
Dudukalov, Yuri, Ternyuk, Mykola, Kholodov, Mykhailo, Hlushkova, Diana, Bushnov, Valery, Sorokin, Volodymyr, Kalashnikov, Yevhen, Savchenkov, Borys
A Study on the Performance and Emissions of HCCI Oxy-Fuel Combustion in a CFR Engine with Recirculated Carbon Dioxide2020-01-206509/15/2020
Stringent emission regulations and the anticipated climate change call for a paradigm shift in the design of the conventional internal combustion engines. One way to combat this problem is oxy-fuel combustion in which the combustion products are mainly water vapor and carbon dioxide. Water vapor can be easily separated by condensation and carbon dioxide is then easily captured and stored. However, many technical challenges are associated with this mode of combustion. There are many challenges facing oxy-fuel combustion before it find its way to commercial production especially for internal combustion engines. One such challenge is the relatively high temperature of the oxy-fuel combustion. A solution to this problem is the recirculation of the generated CO2 to moderate the in-cylinder temperature. Therefore, careful study of the effect of recirculating the CO2 back to combustion chamber is needed before the implementation of such a concept. This study is a continuation of a previous
Mohammed, Abdulrahman, Elkhazraji, Ali, Jan, Sufyan, Johansson, Bengt
Numerical Optimization of a SCR System Based on the Injection of Pure Gaseous Ammonia for the NOx Reduction in Light-Duty Diesel Engines2020-01-035604/14/2020
Selective Catalytic Reduction (SCR) systems are nowadays widely applied for the reduction of NOx emitted from Diesel engines. The typical process is based on the injection of aqueous urea in the exhaust gases before the SCR catalyst, which determines the production of the ammonia needed for the catalytic reduction of NOx. However, this technology is affected by two main limitations: a) the evaporation of the urea water solution (UWS) requires a sufficiently high temperature of the exhaust gases and b) the formation of solid deposits during the UWS evaporation is a frequent phenomenon which compromise the correct operation of the system. In this context, to overcome these issues, a technology based on the injection of gaseous ammonia has been recently proposed: in this case, ammonia is stored at the solid state in a cartridge containing a Strontium Chloride salt and it is desorbed by means of electrical heating. In this work, an after-treatment system based on the injection of gaseous
Della Torre, Augusto, Montenegro, Gianluca, Onorati, Angelo, Cerri, Tarcisio, Tronconi, Enrico, Nova, Isabella
Thermometer Can Be Stretched and Crumpled by WaterTBMG-3641204/01/2020
Researchers recently developed a stretchable and crumpling polymer ionic conductor to realize a thermal sensor that could measure body temperature by simple contacts such as wearing clothes or shaking hands and an actuator that could control movements of artificial muscle.
Liquid Flow Influenced by a Quantum Effect in WaterTBMG-3602802/01/2020
Water is the basis of all life on earth. Its structure is simple — two hydrogen atoms bound to one oxygen atom — yet its behavior is unique among liquids, and scientists still do not fully understand the origins of its distinctive properties.
Ultra-Thin Layers of Rust Generate Electricity from Flowing WaterTBMG-3572212/01/2019
Research shows that thin films of rust (iron oxide) can generate electricity when saltwater flows over them. These films represent an entirely new way of generating electricity and could be used to develop new forms of sustainable power production.
Battery-Free Sensor for Underwater UseTBMG-3544311/01/2019
To investigate oceans, researchers aim to build a submerged network of interconnected sensors that sends data to the surface. Supplying constant power to scores of sensors designed to stay for long durations underwater has been a major problem.
Analysis of a Coupling System of Aircraft Environmental Control and Fuel Tank Inerting Based on Membrane Separation2019-01-189509/16/2019
This paper raises a coupling system of aircraft environmental control and fuel tank inerting based on membrane separation. The system applies a membrane dehumidifier to replace water vapor removal unit of heat regenerator, condenser and water separator, which is widely used in conventional aircraft environmental control system (ECS) nowadays. Water vapor can travel across the membrane wall under its pressure difference without phase change, so the dehumidification process consumes no cooling capacity as traditional ECS and the cooling capacity of the new system increases. This paper first compares the thermodynamic properties of ECS based on membrane dehumidification and the traditional ECS based on condensation. The results show that the membrane dehumidification system has larger cooling capacity and lighter weight. For a given cooling capacity requirement, the membrane dehumidification system can use less bleed air since the enthalpy of the outlet air is lower. Besides, the fuel
Yuan, Weixing, Zheng, Yan, Hou, Jiaqi
Test Method for Measuring Wet Color Transfer CharacteristicsJ1326_201906 (Current)06/25/2019
This procedure describes a method of measuring the resistance to wet color transfer of materials such as textiles, leather, and composites.
Textile and Flexible Plastics Committee
Experimental Investigation of the Droplet Field of a Rotating Vehicle Tyre2019-01-506806/18/2019
The consideration of vehicle soiling in the development process becomes ever more important because of the increasing customer demands on current vehicles and the increased use of camera and sensor systems due to autonomous driving. In the process of self-soiling, a soil-water mixture is whirled up by the rotation of the car’s own wheels and deposits on the vehicle surface. The validation of the soiling characteristics in vehicle development usually takes place in an experimental manner, but is increasingly supported by numerical simulations. The droplet field at the tyre has been investigated several times in the past. However, there are no published information regarding the physical background of the droplet formation process and the absolute droplet sizes considering the position at the tyre and the behaviour at different velocities. In the numerical self-soiling simulations, this droplet whirl up process is modelled by a non-rotating wheel, where equally sized droplets are
Strohbücker, Veith, Niesner, Reinhold, Schramm, Domenik, Kuthada, Timo, Joos, Franz
Analysis and Automated Detection of Ice Crystal Icing Conditions Using Geostationary Satellite Datasets and In Situ Ice Water Content Measurements2019-01-195306/10/2019
Recent studies have found that high mass concentrations of ice particles in regions of deep convective storms can adversely impact aircraft engine and air probe (e.g. pitot tube and air temperature) performance. Radar reflectivity in these regions suggests that they are safe for aircraft penetration, yet high ice water content (HIWC) is still encountered. The aviation weather community seeks additional remote sensing methods for delineating where ice particle (or crystal) icing conditions are likely to occur, including products derived from geostationary (GEO) satellite imagery that is now available in near-real time at increasingly high spatio-temporal detail from the global GEO satellite constellation. A recent study using a large sample of co-located GEO satellite and in-situ isokinetic evaporator probe (IKP-2) total water content (TWC) datasets found that optically thick clouds with tops near to or above the tropopause in close proximity (≤ 40 km) to convective updrafts were most
Bedka, Kristopher, Yost, Christopher, Nguyen, Louis, Strapp, J. Walter, Ratvasky, Thomas, Khlopenkov, Konstantin, Scarino, Benjamin, Bhatt, Rajendra, Spangenberg, Douglas, Palikonda, Rabindra
Uncertainty of the Ice Particles Median Mass Diameters Retrieved from the HAIC-HIWC Dataset: A Study of the Influence of the Mass Retrieval Method2019-01-198306/10/2019
In response to the ice crystal icing hazard identified twenty years ago, aviation industry, regulation authorities, and research centers joined forces into the HAIC-HIWC international collaboration launched in 2012. Two flight campaigns were conducted in the high ice water content areas of tropical mesoscale convective systems in order to characterize this environment conducive to ice crystal icing. Statistics on cloud microphysical properties, such as Ice Water Content (IWC) or Mass Median Diameter (MMD), derived from the dataset of in situ measurements are now being used to support icing certification rulemaking and anti-icing systems design (engine and air data probe) activities. This technical paper focuses on methodological aspects of the derivation of MMD. MMD are estimated from PSD and IWC using a multistep process in which the mass retrieval method is a critical step. Complementary to previous studies reporting on MMD values calculated from the HAIC-HIWC dataset, this paper
Coutris, Pierre, Schwarzenboeck, Alfons, Leroy, Delphine, Grandin, Alice, Dezitter, Fabien, Strapp, J. Walter
Extension of a 2D Algorithm for Catch Efficiency Calculation to Three Dimensions2019-01-201306/10/2019
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
Simulations of Thin Film Dynamics on a Flat Plate and an Airfoil2019-01-193806/10/2019
The goal of the present study is to investigate the dynamics of a thin water film on a flat plate and an airfoil using direct numerical simulation (DNS). The first case for a wetted flat plate is used to model former experiments and investigate the dynamics of a wind-driven water film. The second case for a thin film on a NACA 0012 airfoil of chord length 0.5 m is used to investigate the dynamics of a wind-driven water film on a curved surface. Particular attention is paid to the interaction between the liquid film and the air shear-layer above the film. As the incoming airflow moves over the thin water film, instability is triggered at the gas-liquid interface. Interfacial waves develop and are advected downstream. The interaction between the air flow and the interfacial waves induces shedding vortices near the interface, which in turn perturb the liquid film farther downstream. Simulations are performed using the open source multiphase flow solvers, Gerris and Basilisk. Both solvers
Sakakeeny, Jordan, McClain, Stephen T., Ling, Yue
SLD and Ice Crystal Discrimination with the Optical Ice Detector2019-01-193406/10/2019
In response to new safety regulations regarding aircraft icing, Collins Aerospace has developed and tested an Optical Ice Detector (OID) capable of discriminating among icing conditions appropriate to Appendix C and Appendix O of 14 CFR Part 25 and Appendix D of Part 33. The OID is a short-range, polarimetric lidar that samples the airstream up to ten meters beyond the skin of the aircraft. The intensity and extinction of the backscatter light correlate with bulk properties of the cloud, such as water content and phase. Backscatter scintillation (combined with the outside air temperature from another probe) signals the presence of supercooled large droplets (SLD) within the cloud-a capability incorporated into the OID to meet the requirements of Appendix O. Recent laboratory and flight tests of the Optical Ice Detector have confirmed the efficacy of the OID to discriminate among the various icing conditions. Drizzle-sized droplets, mixed with a small droplet cloud in the Collins Cloud
Anderson, Kaare J., Ray, Mark D.
An Eulerian Approach with Mesh Adaptation for Highly Accurate 3D Droplet Dynamics Simulations2019-01-201206/10/2019
Two main approaches are available when studying droplet dynamics for in-flight icing simulations: the Lagrangian approach, in which each droplet trajectory is integrated until it impacts the vehicle under study or when it leaves it behind without impact, and the Eulerian approach, where the droplet dynamics is solved as a continuum. In both cases, the same momentum equations are solved. Each approach has its advantages. In 2D, the Lagrangian approach is easy to code and it is very efficient, particularly when used in combination with a panel method flow solver. However, it is a far less practical approach for 3D simulations, particularly on complex geometries, as it is not an easy task to accurately determine the droplet seeding region without a great number of droplet trajectories, dramatically increasing the computing cost. Converting the impact locations into a water collection distribution is also a complex task, since droplet trajectories in 3D can follow convoluted paths. One of
Pueyo, Alberto, Ozcer, Isik, Baruzzi, Guido
Icing Test and Measurement Capabilities of the NRC’s Gas Turbine Laboratory2019-01-194306/10/2019
The National Research Council’s Gas Turbine Laboratory provides industry leading icing facilities that allow manufacturers to develop, validate and certify new products for flight in adverse conditions. This paper shows how NRC measurement techniques are used across the facilities, and presents a literature-review of recently developed capabilities. The overview includes new details on some facilities, and future capabilities that are in development or planned for the near future. Methods developed at the NRC for characterizing inclement conditions are discussed and include the Isokinetic Probe, Particle Shadow Velocimetry, the Particle Detection Probe, and a size-binned real-time thermodynamic evaporation model. These are used to deliver accurate icing water content in facilities like the sea-level ice crystal generator, the Rotating Icing Rig, the Research Altitude Testing Facility, and liquid water test facilities in Ottawa and in Thompson, Manitoba at the Global Aerospace Centre
Chalmers, Jennifer, Davison, Craig, MacLeod, James, Neuteboom, Martin, Fuleki, Dan
An Experimental Investigation of a Wind-Driven Water Droplet over the Slippery Liquid Infused Porous Surface2019-01-195106/10/2019
The promising anti-icing performance of the slippery liquid infused porous surface (SLIPS) has been recently demonstrated for various engineering applications. The runback icing for aircraft and wind turbines could be effectively mitigated considering the timely removal of water droplet by the wind shearing force due to the low adhesion on the SLIPS. In this study, the flow field both inside and around the wind-driven droplet over the SLIPS was experimentally investigated by using Particle Image Velocimetry (PIV) technique. Previous studies majorly focus on the internal flow pattern before the droplet incipient motion. In this study, the flow field inside a moving droplet was firstly investigated. As a result of the low surface adhesion of the SLIPS, droplet oscillations were eliminated and the droplet internal flow field could be corrected from the optical distortion. Besides the discussion on the wind speed, the droplet viscosity was also studied by varying the water concentration of
Ma, Liqun, Hu, Hui
Predicted Ice Shape Formations on a Boundary Layer Ingesting Engine Inlet2019-01-202506/10/2019
Computational ice shapes were generated on the boundary layer ingesting engine nacelle of the D8 Double Bubble aircraft. The computations were generated using LEWICE3D, a well-known CFD icing post processor. A 50-bin global drop diameter discretization was used to capture the collection efficiency due to the direct impingement of water onto the engine nacelle. These discrete results were superposed in a weighted fashion to generate six drop size distributions that span the Appendix C and O regimes. Due to the presence of upstream geometries, i.e. the fuselage nose, the trajectories of the water drops are highly complex. Since the ice shapes are significantly correlated with the collection efficiency, the upstream fuselage nose has a significant impact on the ice accretion on the engine nacelle. These complex trajectories are caused by the ballistic nature of the particles and are thus exacerbated as particle size increases. Shadowzones are generated on the engine nacelle, and due to
Porter, Christopher
Numerical Modelling of Primary and Secondary Effects of SLD Impingement2019-01-200206/10/2019
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
Ice Nucleation in the Presence of Electric Fields: An Experimental Study2019-01-202006/10/2019
In the present study, ice nucleation in sessile water drops during continuous cool down is studied experimentally under the impact of a constant electric field, to determine its influence on heterogeneous nucleation. The experimental setup enables simultaneous observation of multiple drops under well-defined conditions with and without an electric field and at temperatures down to -40 °C. A single experimental run contains 40 drops exposed to the same conditions. Drops with a well-defined size are produced employing a drop-on-demand drop generator. Based on multiple experimental runs using the same drops, the nucleation behavior is analyzed using statistical methods to determine the drop survival curves and nucleation site densities for varying conditions. Besides the influence of the electric field, the influence of different drop ensembles is investigated for a constant cooling rate of 5 K/min. A comparison of the experiments with and without an electric field is used to elaborate
Löwe, Jens-Michael, Schremb, Markus, Hinrichsen, Volker, Tropea, Cameron
Summary of the High Ice Water Content (HIWC) RADAR Flight Campaigns2019-01-202706/10/2019
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
A Three-Layer Thermodynamic Model for Ice Crystal Accretion on Warm Surfaces: EMM-C2019-01-196306/10/2019
Ingestion of high altitude atmospheric ice particles can be hazardous to gas turbine engines in flight. Ice accretion may occur in the core compression system, leading to blockage of the core gas path, blade damage and/or flameout. Numerous engine powerloss events since 1990 have been attributed to this mechanism. An expansion in engine certification requirements to incorporate ice crystal conditions has spurred efforts to develop analytical models for phenomenon, as a method of demonstrating safe operation. A necessary component of a complete analytical icing model is a thermodynamic accretion model. Continuity and energy balances are performed using the local flow conditions and the mass fluxes of ice and water that are incident on a surface to predict the accretion growth rate. In this paper, a new thermodynamic model for ice crystal accretion is developed through adaptation of the Extended Messinger Model (EMM) from supercooled water conditions to mixed phase conditions (ice
Bucknell, Alexander, McGilvray, Matthew, Gillespie, David, Jones, Geoffrey, Collier, Benjamin
Type IV Anti-Icing Fluid Subjected to Light Freezing Rain: Visual and Thermal Analysis2019-01-197106/10/2019
Deicing the aircraft using fluid, prior takeoff is mandatory; since a thin layer of ice or snow can compromise the safety. With the same idea, to use anti-icing fluid during a frozen precipitation to protect the aircraft is also essential. Commercialized anti-icing fluids all pass the process of qualification as described in the SAE documents. One of these documents specifies a set of tests that reproduce freezing precipitation to obtain endurance time and then the holdover timetables. The endurance time is determined by visual inspection: when 30% of the plate is covered with frozen contaminants. With the evolution of technology and the venue of new tools, it may simplify the process, and at least confirm the observations. This paper proposed a thermal and visual analysis of the behavior of a Type IV fluid subjected to light freezing rain. During the precipitation, the plate temperature is measured with thermocouples and recorded using a visual camera and an IR camera. The use the
Brassard, Jean-Denis, Laforte, Caroline, Volat, Christophe
Motivation, Development and Verification of a Rapid 3D Lagrangian Impingement Code - Trajectory and Catch 3D+ (TAC3D+)2019-01-201106/10/2019
This paper details the motivation, development and validation of a rapid 3D Lagrangian impingement code, Trajectory and Catch 3D+ (TAC3D+). AeroTex’s motivation to develop a 3D Lagrangian method was primarily driven by the inherent mesh dependent dissipation effect found in their 3D Eulerian Water Catch code (EWC) [1]. Studies performed by AeroTex have shown that for geometries where there are aft impingement regions that are partly shadowed by a more forward impingement region, the level of water flux dissipation can be significant, particularly if the mesh is coarse and the impingement region is far aft. Examples of issues where this may be a particular issue would be impingement on a centerline aft mounted engine or the calculation of impingement on the wing root/belly fairing. The code has been developed around a modified version of the OpenFOAM Lagrangian solver. The analysis process consists of three main phases; a coarse droplet trajectory calculation to identify the region of
Roberts, Ian
Microwave Technique for Liquid Water Detection in Icing Applications2019-01-193006/10/2019
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
An Explorative Study to Use Super-Hydrophilic/Super-Hydrophobic Hybrid Surfaces for Aircraft Icing Mitigation2019-01-199506/10/2019
An explorative study was performed to demonstrate the feasibility of using a novel hybrid anti-/de-icing strategy for aircraft icing mitigation. The hybrid method was developed by combining the electro-thermal heating mechanism and specialized surfaces/coatings with different wettabilities. While an electrical film heater was utilized to provide thermal energy around the leading edge of a NACA0012 airfoil model, two different coating strategies, (i.e., (a). Superhydrophobic coating covering the entire airfoil surface to increase droplets bounce-off and accelerate surface water runback vs. (b). super-hydrophilic coating at the leading edge to increase evaporation area + superhydrophobic coating in downstream to prevent runback refreezing) were proposed and evaluated aiming at maximizing the anti-/de-icing efficiency of the hybrid method. While a series of experiments were conducted to examine the dynamics of droplet impinging onto the different surfaces (i.e., superhydrophobic vs. super
Hu, Haiyang, Hu, Hui, Liu, Yang
An Experimental Study to Evaluate the Droplet Impinging Erosion Characteristics of an Icephobic, Elastic Soft Surface2019-01-199706/10/2019
Elastic soft material/surface, such as Polydimethylsiloxane (PDMS), is a perspective, useful and low-cost hydrophobic and icephobic coating. While it has been reported to have good mechanical durability, its erosion durability under the high impacting of water droplets pertinent to aircraft inflight icing phenomena has not been explored. In this study, the droplet imping erosion characteristics of an icephobic PDMS surface/material is evaluated systematically upon the dynamic impinging of water droplets at different impact velocities (~ up to 75m/s), in comparison with other state-of-the-art icephobic materials/surfaces, such as superhydrophobic surface (SHS) and slippery liquid-infused porous surface (SLIPS). Surprisingly, the contact angle (CA) of the elastic PDMS is shown to have an over 20° increase (from 105° to 128°), which represents better hydrophobicity, after the erosion test which is mainly contributed to the higher roughness of the eroded PDMS surface. As for the
Ma, Liqun, Zhang, Zichen, Liu, Yang, Hu, Hui
Fuel Reforming and Catalyst Deactivation Investigated in Real Exhaust Environment2019-01-031504/02/2019
Increased in-cylinder hydrogen levels have been shown to improve burn durations, combustion stability, HC emissions and knock resistance which can directly translate into enhanced engine efficiency. External fuel reformation can also be used to increase the hydrogen yield. During the High-Efficiency, Dilute Gasoline Engine (HEDGE) consortium at Southwest Research Institute (SwRI), the potential of increased hydrogen production in a dedicated-exhaust gas recirculation (D-EGR) engine was evaluated exploiting the water gas shift (WGS) and steam reformation (SR) reactions. It was found that neither approach could produce sustained hydrogen enrichment in a real exhaust environment, even while utilizing a lean-rich switching regeneration strategy. Platinum group metal (PGM) and Ni WGS catalysts were tested with a focus on hydrogen production and catalyst durability. Although 4% additional hydrogen was initially produced in the EGR stream, leading to improvements in the coefficient of
Bartley, Gordon, Gukelberger, Raphael, Henderson, Robert, Henry, Cary
Regional Hydrologic Extremes Assessment System (RHEAS) SoftwareTBMG-3414504/01/2019
Drought is Africa’s principal type of natural disaster and is at the core of serious threats to the livelihoods of millions of people and the natural resources on which they depend. The economies of many African countries are based on agricultural activities that are controlled mainly by rainfall amounts and distribution; thus, food security in the region is highly vulnerable to impacts of drought.
Theoretical Modeling of the Mechanical Degradation of Polymer Composites due to Moisture/Water Absorption and Damage Progression2019-01-137603/19/2019
The moisture/water absorption and microvoids/cracks progression are two well-understood mechanisms that have significant degradation effects on the mechanical properties/behaviors of the polymer-based composites. To theoretically investigate the effects of above two mechanisms, we develop a simple fiber reinforced polymer composites model by employing the internal state variable (ISV) theory. The water content and the anisotropically distributed damage of the composites are considered as two ISVs (the water content is described by a scalar variable and the damage is defined as a second order tensor) whose histories are governed by two specific physically-based evolution equations. The proposed model can be easily cast into a general theoretical framework to capture more polymer composites behaviors such as viscoelasticity, viscoplasticity and the thermal effect. The results predicted by current model are in good agreement with the experimental data, which allows us to implement the
He, Ge, Liu, Yucheng
Water Injection Benefits in a 3-Cylinder Downsized SI-Engine2019-01-003401/15/2019
With progressing electrification of automotive powertrains and demands to meet increasingly stringent emission regulations, a combination of an electric motor and downsized turbocharged spark-ignited engine has been recognized as a viable solution. The SI engine must be optimized, and preferentially downsized, to reduce tailpipe CO2 and other emissions. However, drives to increase BMEP (Brake Mean Effective Pressure) and compression ratio/thermal efficiency increase propensities of knocking (auto-ignition of residual unburnt charge before the propagating flame reaches it) in downsized engines. Currently, knock is mitigated by retarding the ignition timing, but this has several limitations. Another option identified in the last decade (following trials of similar technology in aircraft combustion engines) is water injection, which suppresses knocking largely by reducing local in-cylinder mixture temperatures due to its latent heat of vaporization. Addition of adequate water can lead to
Khatri, Jayesh, Denbratt, Ingemar, Dahlander, Petter, Koopmans, Lucien
NOx-Conversion Comparison of a SCR-Catalyst Using a Novel Biomimetic Effervescent Injector on a Heavy-Duty Engine2019-01-004701/15/2019
NOx pollution from diesel engines has been stated as causing over 10 000 pre-mature deaths annually and predictions are showing that this level will increase [1]. In order to decrease this growing global problem, exhaust after-treatment systems for diesel engines have to be improved, this is especially so for vehicles carrying freight as their use of diesel engines is expected to carry on into the future [2]. The most common way to reduce diesel engine NOx out emissions is to use SCR. SCR operates by injecting aqueous Urea solution, 32.5% by volume (AUS-32), that evaporates prior the catalytic surface of the SCR-catalyst. Due to a catalytic reaction within the catalyst, NOx is converted nominally into Nitrogen and Water. Currently, the evaporative process is enhanced by aggressive mixer plates and long flow paths. The mixer plates create extra exhaust back pressure and cool the exhaust gases, which decreases engine and catalyst efficiency, resulting in overall poor NOx conversion (<40
Larsson, Peter, Ravenhill, Paul, Tunestal, Per
Contaminants Affecting the Formation of Soft Particles in Bio-Based Diesel Fuels during Degradation2019-01-001601/15/2019
Renewable fuels are essential in the field of heavy duty transportation if we are to reach a fossil-free society in the foreseeable future. However renewable diesel fuels based on fatty acid methyl ester (FAME) might face problems with degradation and with cold flow properties. From the perspective of an engine, this may cause problems in the fuel injection system, such as fuel filter clogging and injector deposits. These phenomena, especially fuel filter clogging, can be connected to gel-like soft particles, which could originate from degradation products as well as from byproducts created during biodiesel refining. In this study, soft particles from the degradation of bio-based diesel fuel were examined. The tested fuels included hydrogenated vegetable oils (HVO), rapeseed methyl ester (RME) and 10% blend of rapeseed methyl ester with standard diesel (B10). To test their potential to increase the formation of soft particles, contaminants such as water, metals and engine oil were
Csontos, Botond, Alim, Richard, Bernemyr, Hanna, Hittig, Henrik, Pach, Mayte
Products of Tomorrow: January 2019TBMG-3359401/01/2019
This column presents technologies that have applications in commercial areas, possibly creating the products of tomorrow. To learn more about each technology, see the contact information provided for that innovation.
The Distributed Simulation of Intelligent Terrain Exploration2018-01-191510/30/2018
In this study we consider the coordinated exploration of an unfamiliar Martian landscape by a swarm of small autonomous rovers, called Swarmies, simulated in a distributed setting. With a sustainable program of return missions to and from Mars in mind, the goal of said exploration is to efficiently prospect the terrain for water meant to be gathered and then utilized in the production of rocket fuel. The rovers are tasked with relaying relevant data to a home base that is responsible for maintaining a mining schedule for an arbitrarily large group of rovers extracting water-rich regolith. For this reason, it is crucial that the participants maintain a wireless connection with one another and with the base throughout the entire process. We describe the architecture of our simulation which is composed of HLA-compliant components that are visualized via the Distributed Observer Network tool developed by NASA. Additionally, a well-known terrain exploration algorithm, which takes the
Anekstein, David, Cornett, Jacob, Guerrero, Marc, Williamson, Cory
Water Load Determination Approach in Two Wheeler Exhaust System2018-32-007510/30/2018
Future emission norms in India (BS6) necessitates the 2 wheeler industry to work towards emission optimization measures. Engine operation at stoichiometric Air-Fuel Ratio (AFR) would result in a good performance, durability and least emissions. To keep the AFR close to stoichiometric condition, an Oxygen sensor is placed in the exhaust system, which detects if air-fuel mixture is rich (λ<1) or lean (λ>1) and provides feedback to fuel injection system for suitable fuel control. O2 sensor has a ceramic element, which needs to be heated to a working temperature for its functioning. The ceramic element would break (thermal shock) if water in liquid form comes in contact with it when the element is hot. To counter this, oxygen sensor is either fully heated only when all the water in the exhaust system is evaporated, which results in delayed closed loop control, or is capable to withstand higher amount of water in the exhaust system by for example being applied with thermal shock protection
Meena, Ranjana Kumari, Krusch, Andrea, Meister, Konrad, Holzknecht, Christopher
Evaluation of Atomization Timing and Optimal Water Content for an Emulsified Fuel Droplet2018-32-005910/30/2018
The emulsified fuel means that it is mixed fuel with water and stabilized by surfactant. The difference of boiling points between fuel and water occur the secondary atomization during heating process. The water content strongly influence on the timing of secondary atomization(1). However, the water content is determined empirically. It means that it is the doubtful of compatibility fuel and a combustor. Then the emulsified fuel is needed the engineering evaluation (not empirically) to take advantage of sure secondary atomization. This research focuses on the timing and behavior of secondary atomization with an emulsified fuel droplet and the proposal of engineering evaluation. Moreover, we propose novel test method without the suspending wire to avoid heat transfer from itself. Namely, the novel point is heating process by floating in the high temperature silicone oil. This method can reveal the atomization behavior of a fuel droplet similar to the spray combustion. The measured data
Aoki, Junichi, Tanaka, Junya
Effects of the Metal Surface Profile to the Sliding Properties between Rubber and Metal and Applying That to Wheel Bearing Seals2018-01-190410/05/2018
Cartridge seals are frequently utilized in wheel bearings where a high level of reliability is required. The cartridge seal combines two components; a seal with flexible rubber lips and a stamped metal slinger that provides a surface for the seal lips to contact without being exposed directly to foreign substances. This paper provides a fundamental evaluation of the sliding properties of rubber seal lips relative to the slinger metal surface profile and evaluates the performance of rotating torque and muddy water endurance from a recommend metal surface profile (developed by advanced fundamental evaluation) of the slinger. Seals with the recommend metal surface profile showed approximately 30% lower torque at the rotating speed from 400 rpm to 800 rpm, which are the speeds representative of automotive city driving. At the same time, the durability performance against muddy water was almost equivalent to the seals without this metal surface.
Ishida, Koki, Fujii, Masahiro, Cho, Jun Hwi, Pittel, Kevin
The Use of Ozone in Low Temperature Methane Control for Natural Gas Applications2018-01-170209/10/2018
Lean operating natural gas heavy duty applications have advantages in terms of lower CO2 and PM compared to Diesel applications. This makes operating heavy duty applications on natural gas attractive and currently, they do not have to implement an exhaust particulate filter. However, the challenge is controlling methane emissions over a range of vehicle operating conditions. Methane is extremely stable and light off occurs at temperatures above 400 °C, with high efficiency occurring >500 °C and requires high precious metal loaded catalysts in the range of 150 - 200 g/ft3. Under stoichiometric conditions, 500 °C can be met in many engine operating points however, for lean operating applications, the exhaust temperature can be significantly lower than 500 °C posing a significant challenge for exhaust catalytic CH4 control. This paper will discuss synthetic gas reactor study results using ozone in the feed gas to perform low temperature methane control. A range of catalysts were
Keenan, Matthew, Nicole, Jacques, Poojary, Damodara
Simulation of Intake Manifold Water Injection in a Heavy Duty Natural Gas Engine for Performance and Emissions Enhancement2018-01-165309/10/2018
The present work discusses the effects of intake manifold water injection in a six-cylinder heavy duty natural gas (NG) engine through one-dimensional simulation. The numerical study was carried out based on GT-Power under different engine working conditions. The established simulation model was firstly calibrated in detail through the whole engine speed sweep under full load conditions before the model of intake manifold water injector was involved, and the calibration was based on experimental data. The intake manifold water injection mass was controlled through adjustment of intake water/gas (water/natural gas) ratio, a water/gas ratio swept from 0 to 4 was selected to investigate the effects of intake manifold water injection on engine performance and emissions characteristics. On the other hand, the enhancement potential of intake manifold water injection in heavy duty NG engine under lean and stoichiometric condition was also investigated by the alteration of air-fuel ratio. The
Kang, Zeqi, Kang, Zhe, Jiang, Lang, Deng, Jun, Wu, Zhijun, Li, Liguang, Liang, Heping, Shu, Mingyu
Effect of Water Injection and Spatial Distribution on Combustion, Emission and Performance of GDI Engine-A CFD Analysis2018-01-172509/10/2018
Water injection in diesel engines is a successful way to reduce NOx emissions and enhance brake power output. The advantages of water injection are because of its high enthalpy of vaporization and high specific heat capacity by which it absorbs heat from the in-cylinder mixture. The benefits of water injection depend on the rate of water vaporization and its spatial distribution in the combustion chamber. However, detailed effects of these parameters are very rarely studied in the past. Therefore, in the present study, an attempt has been made to assess the effect of water injector configuration on performance of a GDI engine by CFD analysis. Here, the analysis is done mainly to study and enhance the evaporation and spatial distribution characteristics of the water injection inside the combustion chamber. Water is directly injected into the cylinder of a naturally aspirated, four-stroke GDI engine. Various water injection configurations formed by different spray patterns and injector
Raut, Ankit Ashokrao, Mallikarjuna, J M
Effects of Clamping Force on the Operating Behavior of PEM Fuel Cell2018-01-171809/10/2018
Proton exchange membrane (PEM) fuel cell is widely recognized as an outstanding portable power plant and expected to be possibly commercialization in the near future. As is well known, mechanical stresses implemented on the bipolar plates during the assembly procedure should have prominent influences on mass and heat transfer behavior inside the cell, as well as the resultant performance. In this study, an analytical model is proposed to comprehensively investigate the influence of clamping force on the mass transport, electrochemical properties and overall cell output capability of a PEM fuel cell. The results indicate that proper clamping force not only benefits the gas leakage prevention but also increases the contact area between the neighboring components to decrease the contact ohmic resistance. However, deformation always takes place simultaneously, changing the local physical structures of the cell components, which possibly leads to the decrement of porosity and permeability
Chen, Rouxian, Qin, Yanzhou, Du, Qing, Peng, Jun
HOSE ASSEMBLY, LINED SILICONE, 125 PSI, FLARELESS TO FIXED CAVITY, POTABLE WATERAS5503B (Current)08/14/2018
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
Water-Based Battery Stores Solar and Wind EnergyTBMG-3247608/01/2018
Wind and solar energy generation creates challenges, since the Sun only shines by day, and sometimes the wind doesn't blow. Another variability is surges of demand on the grid. On a hot day when air conditioning is in use, utilities must have load-balancing strategies to meet peak demand. A water-based battery was developed that could provide a cheap way to store wind or solar energy generated when the Sun is shining and wind is blowing so it can be fed back into the electric grid and be redistributed when demand is high.
Artificial “Blubber” Protects Divers in Frigid WaterTBMG-3248208/01/2018
When Navy SEALs carry out dives in Arctic waters, or when rescue teams are diving under ice-covered rivers or ponds, the survival time even in the best wetsuits is very limited — as little as tens of minutes. Researchers have discovered a process to triple that survival time.
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