Browse Topic: Water

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This Aerospace Information Report (AIR) outlines the design considerations and criteria for the control of water carryover from the environmental control system (ECS) with respect to causes and indicated corrective or preventative action. In addition, condensation on structure will be reviewed with possible preventative action described.
AC-9 Aircraft Environmental Systems Committee
NASA’s Johnson Space Center is offering an innovative freeze-resistant hydration system for licensing. The technology substantially improves on existing hydration systems because it prevents water from freezing in the tubing, container, and mouthpiece, even in the harshest conditions on Earth.
The improvement of vehicle soiling behavior has increasing interest over the past few years not only to satisfy customer requirements and ensure a good visibility of the surrounding traffic but also for autonomous vehicles, for which soiling investigation and improvement are even more important due to the demands of the cleanliness and induced functionality of the corresponding sensors. The main task is the improvement of the soiling behavior, i.e., reduction or even prevention of soiling of specific surfaces, for example, windows, mirrors, and sensors. This is mostly done in late stages of vehicle development and performed by experiments, e.g., wind tunnel tests, which are supplemented by simulation at an early development stage. Among other sources, the foreign soiling on the side mirror and the side window depend on the droplet detaching from the side mirror housing. That is why a good understanding of the droplet formation process and the resulting droplet diameters behind the side mirror is necessary, including all the possible influencing factors. A first fundamental study was already investigated by the authors at a vehicle side mirror using a modified wind tunnel soiling test rig [1]. In the current study, a generic plate with a defined edge for droplet detachment is placed inside the open jet of a calibration wind tunnel. The aim of the investigation is to test different parameters of the detachment process and to analyze the resulting droplet sizes behind the generic edge. Parameters such as the radius of the detachment edge, the liquid, and the volumetric flow rate are varied and their influence on the atomization as well as soiling processes is analyzed using shadowgraphy measuring technique and high-speed video recording. Our results show that the droplet detachment behind a generic plate can be divided into two separate topics: the detachment position and the detachment process. The detachment position is dependent on the air velocity and the edge radius. With an increased radius and an increased velocity, the water can stay longer wall-bound and detach further downstream. The detachment process at the edge shows two different ligament formation processes independent of the air velocity: ligament formation and ligament-bag formation. A secondary breakup process may occur for droplets in the air, where four different processes are observed, covering vibration breakup, bag breakup, bag-and-stamen breakup, and sheet thinning. In all tested variations, most of the droplets show a diameter of about 65 μm.
Kille, LukasStrohbücker, VeithNiesner, ReinholdSommer, OliverWozniak, Günter
This SAE Aerospace Standard (AS) covers water conditioning agents used to facilitate aqueous wet-method magnetic particle inspection.
AMS K Non Destructive Methods and Processes Committee
Brazil has a robust agricultural sector; however, the mechanization of crops causes several problems in the physical soil structure, including surface compaction. Compaction reduces crop productivity and producer profits. The intensity of compaction varies depending on the wheelset model used, tire type, water content, and soil load applied. Recent studies have shown that soil compaction in sugarcane can be attenuated by maintaining the vegetation cover (straw biomass) on the surface after harvesting. The present study used different tire models to evaluate the interaction between wheelset-soil as a function of different amounts of biomass left over from the sugarcane harvest. A physical simulation system (fixed tire testing unit) was used for the tests. The wheelsets were subjected to controlled loads on tanks with confined and standardized soil samples. The treatments consisted of 3 tire models (p1: road radial, composed of double wheelset - 2×275/80R22.5; p2: agricultural radial - 600/50R22.5; and p3: agricultural diagonal - 600/50-22.5) and three contact surfaces (s1: without vegetation cover; s2: soil with straw cover equivalent to 15mg ha-1; and s3: soil with 30Mg ha-1 vegetation cover), considering three replications. We performed principal component analysis (PCA) and regression analysis to results. We verified tire-soil contact area (CA) increased with the increase straw coverage and was inversely proportional to soil resistance penetration (PC). The highest resistance to soil penetration was obtained with the p1 tire on uncovered soil (s1). Road tires cause intense impact when no vegetation covers. We verified that intensity impact caused by the wheelsets in the crop would be determined by cover straw and tire model. For better results to soil preservation, it must maintain a minimum of 15Mg ha-1 of coverage biomass.
Filho, Aldir Carpes MarquesSartorio, Simone D. M.Martins, Murilo B.Lanças, Kléber P.
A research team has developed diamond quantum sensors that can be used to improve resolution in magnetic imaging. In order to test the method, the scientists placed a microchip with microscopic water-filled channels on the diamond quantum sensor. This allowed the researchers to simulate microstructures of a cell. They were able to successfully analyze the diffusion of water molecules within the microstructure.
In today's world, there is an increasing emphasis on the responsible use of fiber reinforced materials in the automobile applications, construction of buildings, machinery, and appliances as these materials are effectively reused, recycled, or disposed with minimum impact on the environment. As such, it has become mandatory to incorporate sustainable, environmental friendly and green concepts in the development of new materials and processes. The primary objective of this study is to manufacture composites using fibers obtained from Thespesia Lampas plants, which are known for their soft, long fibers that are commonly used in various domestic products. The composites are made by combining these fibers with a general purpose polyisocyanurate resin, and their potential applications in both domestic and commercial products are explored. To evaluate the properties of these composites, tests are conducted for tensile strength, flexure, and water absorption. The laminates are fabricated using both unidirectional and cross woven mats to assess its effect on the properties. In addition, the impact of NaOH treatment at different proportions on the properties of the fiber composites is also investigated. The laminates are fabricated using both unidirectional and cross woven mats to assess its effect on the properties. In addition, the impact of NaOH treatment at different proportions on the properties of the fiber composites is also investigated. The flexural strength of unidirectional treated (4% NaOH) fiber composites was found to be 216.75 MPa. Thespesia Lampas treated (4% NaOH) has a higher ultimate tensile strength of 27.85 MPa. Cross woven laminates have superior water absorption resistance than treated (4% NaOH) unidirectional fiber composite.
Somsole, Lakshmi NarayanaNatarajan, ManikandanPasupuleti, ThejasreeN, Anantha KrishnaKatta, Lakshmi Narasimhamu
Composite materials find extensive applications in numerous fields, including mechanical components, which are often subjected to varying climatic conditions. Due to the contrasting conditions, there is a difference in the external loadings, leading to the transfer of air, heat, and moisture between the environments. Here, the study is done to model the moisture-based diffusion in order to predict the output beforehand so that necessary precautions can be taken before it fails. The study primarily investigates the heat and moisture-based absorption behavior of composite materials. The Representative Volume Element (RVE) approach is chosen, which enables the simulation of the behavior of the composite at a microscale level, giving insights into the micromechanics and analyzing the material absorption behavior of moisture. The FEA approach for the same is carried out using the COMSOL Multiphysics software. The required RVE of the composite is modeled, and the effect of fiber volume fraction on the hygroscopic swelling, followed by the effect on its properties, is derived. Subsequently, the mechanical characterization of the material is performed. The composite model is run through a moisture-based environmental condition, as in the previous case to evaluate the effects of moisture on the strength of the composite material. The material exposed to the moisture environment showed water uptake. The increase in water uptake causes a decrease in the strength of the material compared to the material with no exposure to moisture. The study focuses on the relationship between the composite’s moisture content and its mechanical characteristics, which can be helpful for the responsible modeling of components in the required environment.
Nelson, N Rino
NASA engineers have developed a new approach to mitigating unwanted motion in floating structures. Ideally suited to applications including offshore wind energy platforms and barges, the innovation uses water ballast as a motion damping fluid.
NASA instrumentation is at risk for contamination from dusty space environments. Additionally, contamination from water and ice buildup can affect instrumentation function. Researchers at the Goddard Space Flight Center have developed a viable dust, water, and ice mitigation optical coating for space flight, aeronautical, and ground applications. The innovation of the LOTUS coating prevents contamination on sensitive surfaces, like optics, that cannot be cleaned during space missions.
The growing demand for transportation fuels and the global emphasis on reducing greenhouse gas (GHG) emissions have led to increased interest in analyzing transport GHG emissions from the life-cycle perspective. Methanol, a potentially carbon-neutral fuel synthesized from CO2 and H2, has emerged as a promising candidate. This paper conducts a comprehensive life-cycle analysis (LCA) of the GHG emissions associated with the methanol production process, utilizing data inventory from China in 2019. To simulate the synthesis and distillation process of methanol, Aspen Plus is employed, using parameters obtained from actual plants. GHG emissions are then calculated using the GREET model, incorporating updated industry statistics and research findings. The CO2 necessary for methanol production is captured from factory flue gas. Two different sources of H2 are considered: one from Coke Oven Gas (COG) and the hydrogen-rich gas byproduct resulting from COG methanation (Case 1), and the other via water electrolysis (Case 2). The GHG emissions of methanol production for Case 1 and Case 2 are found to be -0.08 and 6.36 kg CO2-eq/kg methanol, respectively. However, if wind power is the sole source of electricity, the GHG emissions for both cases are reduced to -0.68 and -0.65 kg CO2-eq/kg methanol, respectively. The adoption of CO2 capture technology is the main reason for both systems to achieve negative emissions. The lower GHG emissions in Case 1 are attributed to the energy and emission allocation of byproducts. To achieve net zero GHG emissions in Case 2, the GHG emissions of electricity generation need to be reduced by 88% of the current level. This reduction is expected to be achieved by 2050, based on projected power generation mixes and efficiency improvements in water electrolysis in China.
Fu, YangWang, BuyuShuai, Shijin
The demand for multi-environmental modes of transportation is driven by the overall trend of increasing mobility and the necessity of movement across various alternating environments (land, water, underwater, aerial, and airspace). However, the specific energy density of hydrocarbon fuels cannot ensure efficient operation of power systems for such multi-environmental vehicles. A promising solution to this problem involves the utilization of boron-containing metallized fuels through the creation of specialized fuel supply systems. Based on a general method of optimization synthesis for technical objects, new fuel supply systems were synthesized with different levels of process control and degrees of automation, as well as an adjustable hybrid fuel delivery system that allows the application of components in varying aggregate states. During testing, operational characteristics were determined primarily for the implemented metallic hybrid transformer fuel delivery system. In our view, it holds the greatest potential for the utilization of metallized fuels, as it provides an expanded range of applications, increased functions, and structures. This is also linked to the possibility of employing boron in the α-modification, where atomic-level processes ensure maximum combustion efficiency. Thus, the new fuel supply system offers functionality across diverse environments, creating genuine prerequisites for the efficient operation of power systems for multi-environmental modes of transportation.
Dudukalov, YuriTernyuk, MykolaHlushkova, DianaBushnov, ValerySorokin, VolodymyrKholodov, Mykhailo
As engine technology developed continuously, engine with both turbocharging and EGR has been researched due to its benefit on improving the engine efficiency. Nevertheless, a technical issue has raised up while utilizing both turbocharging and EGR at the same time: excess condensed water existed in intake manifold which potentially trigger misfire conditions. In order to investigate the root-cause, a CFD model (conducted by CONVERGE CFD software) was presented and studied in this paper which virtually regenerated intake manifold flow-field with EGR condensed water inside. Based on the simulated results, it concluded that different initial conditions of EGR condensed water could significantly change the amount of water which deposited in each cylinder. Thus, a coefficient of variation of deposited condensed water amount among these cylinders, was marked as the evaluation reference of cylinder misfire. Theoretically, as this coefficient of variation reduced, the EGR condensed water from intake manifold would be distributed homogeneously in each cylinder, and thus less possibility of cylinder misfire should be observed. As concluded from the presented multiple simulated results, the coefficient of variation of deposited condensed water amount was above 30% statically for the existing intake manifold, which meant the existing intake manifold had tremendous room for optimization. The result showed that the fluctuation of the inner surface of the intake manifold had a great impact on the flow of condensate water, so different surface shapes could be designed in the intake manifold to organize the flow of condensate water, so as to make the condensate water of each cylinder more uniform, and reduce the occurrence of fire.
Pan, ShiyiLi, GuantingWang, JinhuaZhang, NanXu, ZhiqinChen, ShanghuaChen, JunZhao, Shengwei
Dubbed an “engineered living material,” a new type of material developed at the University of California San Diego could offer a sustainable and eco-friendly solution to clean pollutants from water.
Personal devices feed our sight and hearing virtually unlimited streams of information while leaving our sense of touch mostly … untouched.
A Northwestern University research team has developed a revolutionary transistor that is expected be ideal for lightweight, flexible, high-performance bioelectronics. The electrochemical transistor is compatible with blood and water and can amplify important signals.
Researchers from Northwestern University have collaborated on the implementation of an accurate, low-cost, and easy-to-use test for detecting toxic levels of fluoride in water. The new biosensor device has been field tested in Kenya — proving that testing water for fluoride can be easily accomplished outside of a lab and accurately interpreted by nonexperts.
Photosynthesis has evolved in plants for millions of years to turn water, carbon dioxide, and the energy from sunlight into plant biomass and the foods we eat. This process, however, is very inefficient, with only about 1 percent of the energy found in sunlight ending up in the plant. Scientists at UC Riverside and the University of Delaware have found a way to bypass the need for biological photosynthesis altogether and create food independent of sunlight by using artificial photosynthesis.
Recently, lean manufacturing (LM) practices are being combined with tools and techniques that belong to other areas of knowledge such as risk management (RM). Value stream mapping (VSM) is a well-known tool in showing the value, the value stream, and the flow, which represents the three lean principles. VSM and RM, when used in tandem with one another, are more advantageous in covering VSM issues such as the variability of production processes. In this article, a conceptual model that integrates the two is shown and explained. The model helps to generate scenarios of current state map (CSM) and future state map (FSM) in a dynamic way by identifying current and potential risks. These risks might happen in the future, bringing with it negative ramifications including not reaching the main objectives within the defined time. The model has been tested in a coffee production company belonging to health and food sector. The proposed model specified the ranges of variability through the drawing of CSM and FSM. This is quite a milestone because one of the challenges of VSM is that it is a static tool, and, as such, process variability cannot be captured appropriately. This new model is expected to overcome this drawback.
Araibi, Alaa SalahuddinShaiful, A. I. M.Shadhar, Mohanad Hatem
Exploring the possibility of all-weather secure quantum communication using macroscopic quantum states of light. Air Force Research Laboratory, Asian Office of Aerospace Research and Development, Tokyo, Japan More than half a century has passed since the birth of quantum signal detection theory, which is the cornerstone of modern quantum communication theory. Quantum stream cipher, the quantum-noise-based direct encryption scheme for optical communications at the center of our research, is based on the foundations of quantum communication theory. For quantum cryptography to progress from a theoretical possibility to a more realistic technology, experimental and theoretical research must be complementary. We have reported several experimental and theoretical studies on the quantum stream cipher connecting two points via optical fibers and also fabricated a prototype based on them. To enhance the usability of a quantum stream cipher, free-space optical communications must be explored in addition to point-to-point optical communications connected by optical fibers. In the case of free-space optical communications, various environmental changes caused by the weather affect the communication channel. Therefore, quantum communications, including cryptographic applications, must be considered from experimental and theoretical perspectives under various harsh weather conditions such as fog, rain, snow, and turbulence.
More than half a century has passed since the birth of quantum signal detection theory, which is the cornerstone of modern quantum communication theory. Quantum stream cipher, the quantum-noise-based direct encryption scheme for optical communications at the center of our research, is based on the foundations of quantum communication theory. For quantum cryptography to progress from a theoretical possibility to a more realistic technology, experimental and theoretical research must be complementary.
As emission restrictions become more stringent and conventional fuel supplies become more limited, dual-fuel engines are emerging as a promising solution that offers both environmental and economic benefits. However, the performance of these engines is often hampered by the issue of knocking, which can negatively impact their overall operation, and also by the increase in NOx emissions at high load. This work investigates the use of pilot injection properties by combining the use of emulsified diesel of different water percentages with injection timing to reduce both knock intensity and NOx emission rate. Specifically, a dual fuel operation case at full load with high enrichment of the primary fuel (natural gas) with hydrogen is considered in order to create conditions for high knocking and high NOx emission rates. The online optimization principle is used for the creation of the meta-model, utilizing the Radial Basis Functions technique (RBF), and the search for the optimum in parallel using the Non-Dominated Sorting Genetic Algorithm (NSGA-II) to handle two objective functions: the minimization of the knock intensity and NOx emissions, and the maximization of the engine thermal efficiency, based on two decision variables: the volume percentage of water in the emulsified diesel (0-30%) and the injection time of this pilot fuel (5-30° CA BTDC). The evaluation of the cases is provided by a CFD calculation model (Converge©) after validation by experimental results. The results indicate that the amount of water contained in the diesel and the injection time have a significant influence on the knock intensity (a decrease of 74%) and the rate of pollutant emissions (a decrease of 61%). The Pareto front summarizes the non-dominated cases according to the two objective functions and indicates that increasing the percentage of water and delaying the pilot injection decrease both the intensity of the knocking and the NOx emissions but penalizes the thermal efficiency of the engine. Therefore, choosing the optimums is crucial in achieving a compromise between the two objective functions.
Sehili, YoucefLoubar, KhaledTarabet, LyesMahfoudh, CerdounLacroix, Clément
As rains get heavier and more frequent, flooding, especially in cities, is becoming a serious problem. The traditional way of managing stormwater has been to quickly get it off the road and into the storm sewer system to be sent downstream, said Lauren McPhillips, Assistant Professor of civil and environmental engineering and of agricultural and biological engineering at Penn State. “With the stormwater out of sight, the problem was out of mind.” However, whisking the water away increases risks of extreme flooding downstream.
Most of the world is covered in oceans, which are unfortunately highly polluted. One of the strategies to combat the mounds of waste found in these very sensitive ecosystems — especially around coral reefs — is to employ robots to master the cleanup. However, existing underwater robots are mostly bulky with rigid bodies, unable to explore and sample in complex and unstructured environments, and are noisy due to electrical motors or hydraulic pumps. For a more suitable design, scientists at the Max Planck Institute for Intelligent Systems (MPI-IS) in Stuttgart looked to nature for inspiration.
This specification covers a stable, noncorrosive, water-soluble, highly-penetrating, fluorescent solution which may, but need not, be diluted with an appropriate amount of water for use.
AMS K Non Destructive Methods and Processes Committee
In the last decades there have been many temporary engine failures, engine-related events and erroneous airspeed indication measurements that occurred by a phenomenon known as Ice Crystal Icing (ICI). This type of icing mainly occurs in high altitudes close to tropical convection in areas with a high concentration of ice crystals. Direct measurements or in-situ pilot observations of ICI that could be used as a warning to other air-traffic are rare to nearly non-existent. To detect those dangerous high Ice Water Content (IWC) areas with already existing airborne measurement instruments, Lufthansa analyzed observed Total Air Temperature (TAT) anomalies and used a self-developed search algorithm, depicting those TAT anomalies that are related to ice crystal icing events. To optimize the flight route for dispatchers several hours before the flight, e.g. for long distance flights through the intertropical convergence zone (ITCZ), reliable forecasts to identify hazardous high IWC regions are necessary. For this purpose, detected TAT anomalies were used as training data to find correlations in between these and the DWD’s ICON (ICOsahedral Non-hydrostatic) model output. The combination of obtained frequency distributions of model cloud ice water content, base and top of moist convection and specific humidity by a fuzzy logic leads to a model-based prototype to forecast areas with high IWC in a simple manner. To show the high potential of the prototype’s procedure, an ICI event as observed during the CIRRUS-HL (Cirrus in High Latitudes) flight campaign in 2021 serves as good validation case. Here we show first promising, as it is still under development.
Kalinka, FrankButter, MaxJurkat, TinaDe La Torre Castro, ElenaVoigt, Christiane
The paper describes a tools’ suite able of analyzing numerically 3D ice-accretion problems of aeronautical interest. The methodology consists of linking different modules each of them performing a specific function inside the ice-simulation chain. It has been specifically designed from the beginning with multi-step capability in mind. Such a feature plays a key role when studying the dynamic evolution of the icing process. Indeed, the latter has the character of a multi-physic and time-dependent phenomenon which foresees a strong interaction of the air- and water fields with the wall thermodynamics. Our multi-layer approach assumes that the physical problem can be discretized by a series of pseudo-steady conditions. The simulation process starts with the automatic generation of a Cartesian three-dimensional mesh which represents the input for the immersed boundary (IB) RANS solver. Once obtained, the air-phase is used by the Eulerian tool to solve the transport of the water-phase on the same domain-grid. Both the volumetric solvers share the same unstructured data management and the finite-volume (FV) approach which is based on locally refined Cartesian meshes. Part of the research effort is devoted to the development of a thermodynamic 3D method which solves the surface liquid-film by Messinger balances of mass and energy. The main outputs are the equilibrium temperature and the mass of ice. The latter is used to compute the local ice-height for accretion purposes. A Lagrangian modification of the geometry is applied at each step by moving the wall vertices along the local unit normal vector. The modified 3D surface is passed again to the automatic mesher for renewing the computational loop. The accuracy and the limits of the present method are discussed by analyzing the results on three-dimensional benchmarks proposed in the framework of the 1st ice prediction workshop (IPW).
de Rosa, DonatoCapizzano, FrancescoCinquegrana, Davide
Thermal ice protection systems (IPS) are used extensively in aeronautics. They are tailored according to the aircraft characteristics or flight envelope and can be used in different modes, anti-icing to avoid ice accretion or de-icing to remove the ice once accreted. A relevant issue by this application is the runback icing, caused by the downstream flow of melted or running water to unprotected areas, where activation is not possible in terms of energy consumption. Passive systems are being explored to complement or replace active systems, although, up to now, solutions have not been reported with the required performance for real-life applications. One of the most commonly reported anti-icing strategy relays on superhydrophobicity, i.e., it is based on the water roll-off capacity of Cassie-Baxter superhydrophobic surfaces (CB-SHP). Precisely, running wet phenomena, where liquid water is flowing on the surface, could be an appropiate application field for this type of materials. Herein, we have explored the behavior and limitations of a stable, newly developed, CB-SHP material to protect a runback section under icing conditions (temperature, air speed, liquid water content, droplet size distribution, and angle of attack) closer to those encountered in a wing airfoil.Two icing mechanisms, running-wet and direct impingement of supercooled microdroplets, have been evaluated for short (2 minutes) and long (10 minutes) period tests. It is found that the tested SHP material improved the performance of reference polyurethane (PU) paints, avoiding any ice accretion at low air speeds and low angles of attack.
Mora, JulioGarcía, PalomaCarreño, FranciscoMontes, LauraLópez-Santos, CarmenRico, VictorBorras, AnaRedondo, FranciscoGonzález-Elipe, Agustín R.Agüero, Alina
Ice and snow accretion on aircraft surfaces imposes operational and safety challenges, severely impacting aerodynamic performance of critical aircraft structures and equipment. For optimized location-based ice sensing and integrated ‘smart’ de-icing systems of the future, microwave resonant-based planar sensors are presented for their high sensitivity and versatility in implementation and integration. Here, a conformal, planar complementary split ring resonator (CSRR) based microwave sensor is presented for robust detection of localized ice and snow accretion. The sensor has a modified thick aluminum-plate design and is coated with epoxy for greater durability. The fabricated sensor operates at a resonant frequency of 1.18 GHz and a resonant amplitude of -33 dB. Monitoring the resonant frequency response of the sensor, the freezing and thawing process of a 0.1 ml droplet of water is monitored, and a 60 MHz downshift is observed for the frozen droplet. Using an artificial snow chamber to create falling snow, a 1 mm thick accretion of snow shows a 35 MHz downshift in resonant frequency. The proposed sensor system can be extended using a novel radar-inspired method of Time-Domain Reflectometry (TDR). TDR based ice/snow sensors can be implemented in an array or network structure for reliable, local and distributed ice and snow accretion monitoring on aircraft structures. Applying Time-Domain Reflectometry (TDR) methods, three identical sensors with the same resonant frequency are monitored over an approximate length of 10 m and localized sensing of water is presented. This novel method offers a pathway towards implementation of large network-based resonant-microwave sensors for future reliable integrated localized icing and snow accretion rate-measurement sensors.
Shah, AaryamanNiksan, OmidZarifi, Mohammad H.
Threats to aviation safety as a result of super-cooled large drops (SLD) has been addressed by the FAA rules change (14 CFR Part 25) with the additional icing certification requirement. SLD clouds often consist of bi-modal drop size spectra leading to significant problems in simulating and characterizing these conditions in situ and in icing wind tunnels. Legacy instrumentation for measuring drop size distributions and liquid water content are challenged under these conditions. The large size range measurement problem is addressed with the development of the Phase Doppler Interferometer, Flight Probe Dual-Range (PDI FPDR). The method is described in this report along with the measurement capabilities including the dynamic measurement range and overall working size range. The PDI instrument bases drop size measurements on the light wavelength as the measurement length scale. The light wavelength is a much more robust scale, especially as compared to the light scattering intensity. Methods for accurately characterizing the sample volume in situ based on measured drop velocity and transit time are reviewed, given the importance of this parameter for merging results and measuring LWC. Droplet coincidence in the sample volume can be problematic so this condition is treated with an innovative signal parsing approach. Measurement examples acquired in the NASA IRT are provided. Measurements of LWC showed good agreement with the Artium Particle Imaging (PI) instrument but diverged from the tunnel calibration results for larger MVD values.
Bachalo, William DonPayne, GregoryIbrahim, KhalidFidrich, Michael
In the framework of the European ICE GENESIS project (https://www.ice-genesis.eu/), a field experiment was conducted in the Swiss Jura in January 2021 in order to characterize snow microphysical properties and document snow conditions for aviation industry purposes. Complementary to companion papers reporting on snow properties, this study presents an investigation on mixed-phase conditions sampled during the ICE GENESIS field campaign. Using in situ measurement of the liquid and total water content, the ice mass fraction is calculated and serves as a criteria to identify mixed-phase conditions. In the end, mixed phase conditions were identified in almost 30 % of the 3800 km long cloud samples included in the ICE GENESIS dataset. The data suggests that the occurrence of mixed-phase does not clearly depend on temperature in the 0 to -10 °C range, but varies significantly from one cloud system to another. The distribution of mixed phase and liquid only spatial scales cascades from 100 m (instrumental resolution limit) to 12 km, existing most of the time as pockets of few hundreds of meters embedded in larger cloudy areas.
Coutris, PierreFebvre, GuyJaffeux, LouisSchwarzenboeck, AlfonsDezitter, FabienBillault-Roux, Anne-ClaireGrazioli, JacopoBerne, AlexisJorquera, SusanaDelanoe, Julien
The Icing Research Tunnel at NASA Glenn follows the recommended practice for calibration outlined in SAE’s ARP5905. The calibration team has followed the schedule of a full calibration every five years with a check calibration done every six months following. The liquid water content of the IRT has maintained stability within the stated specifications of variation within +/- 10% of the curve fit equation generated from calibration data. Using past measurements and data trends, IRT characterization engineers wanted to develop methods for the ability to know when data were not within variation. Trends can be observed in the liquid water content measurement process by constructing statistical process control charts. This paper describes data processing procedures for the Multi-Element Sensor in the IRT, including collision efficiency corrections, canonical correlation analysis, process for rejection of data, and construction of control charts. Data are presented to display the control capability to meet defined liquid water content specifications of the IRT with the Multi-Element Sensor mounted in the center of the test section.
Timko, EmilyKing-Steen, LauraInsana, Eric
A fundamental understanding of the icing process for aircraft requires a more thorough analysis of the thermodynamics of supercooled droplet impingement. To better study such thermodynamic processes, a novel temperature sensor that functions within supercooled water and ice crystals was developed. The temperature sensor is non-intrusive and provides temperature and phase change information for both liquid water and solid ice. The temperature sensor is an optical sensor based on the luminophore pyranine. The use of pyranine allows for the measurement of spatially and temporally resolved temperature fields for icing applications. The sensitivity of the sensor is -9.2±0.1%/K for temperature measurement in the solid phase and 0.8±0.1%/K for the liquid phase. The performance of the sensor was demonstrated through a calibration process using spectral analysis, the observation of the melting process of a rectangular prism created from the luminescent ice, and the study of the temperature profile of accreted ice onto a cooled surface. Measurements of the melting and accreted ice were performed using a high-speed color camera.
Gonzales, JosephYamazaki, MasafumiSakaue, Hirotaka
This work presents the implementation and validation efforts of a 3D ice accretion solver for aeronautical applications, MESS3D, based on the advanced Messinger model. The solver is designed to deal with both liquid phase and ice crystal cloud conditions. In order to extend the Messinger model to 3D applications, an algorithm for the water run-back distribution on the surface was implemented, in place of an air flow stagnation line search algorithm, which is straightforward in 2D applications, but more complicated in 3D. The developed algorithm aims to distribute the run-back water in directions determined by air pressure gradients or shear forces. The data structure chosen for MESS3D allows high flexibility since it can manage the necessary input solutions on surface grids coming from both structured and unstructured solvers, regardless the number of edges per surface cells. The aim of the work is to present a validation of the model by examining the robustness of the solutions when it deals with 2D configurations and verifying the grid solution independence on 3D configurations in both liquid water droplets and ice crystals environments. The selected test cases are relative to well documented literature cases supported by experimental results from tests conducted at NASA Glenn IRT and NRCC RATFac wind tunnel.
Cinquegrana, DavideD'Aniello, Francescode Rosa, DonatoCarozza, AntonioCatalano, PietroMingione, Giuseppe
Future compliance to FAA 14 CFR Part 25 and EASA CS-25 Appendix O conditions has required icing wind tunnels to expand their cloud simulation envelope, and demonstrate accurate calibration of liquid water content and droplet particle size distributions under these conditions. This has led to a renewed community interest in the accuracy of these calibrations, and the potential inter-facility bias due to the choice of instrumentation and processing methods. This article provides a comparison of the response of various hot-wire liquid water content instruments under Appendix C and supercooled large droplet conditions, after an independent similar analysis at other wind tunnel facilities. The instruments are being used, or are under consideration for use, by facilities collaborating in the ICE GENESIS program. For droplet median volume diameters (MVDs) between about 15 and 250 μm, cylindrical hot wire LWC sensors were found to consistently and increasingly under-read measurements from conical and trough TWC sensors as MVD increased, and were not considered further. Of the remaining TWC sensors, the specific instruments investigated were found to agree within about ± 20% of their average test point response for the range of conditions tested, but systematic scale differences between instruments were found to reach about a factor of 1.4. Sensitivity to increasing droplet MVD was concluded to be similar amongst different instruments given the uncertainties, except for two that exhibited notable roll-off with MVD relative to the others.
Esposito, Biagio M.Orchard, DavidLucke, JohannesNichman, LeonidBliankinshtein, NataliaLilie, LyleCatalano, PietroD'Aniello, FrancescoStrapp, J. Walter
To support an industry wide response to an EASA proposed Special Condition regarding the threat of in-flight supercooled liquid water icing conditions at altitudes above FL300, Boeing 777 fleet data were used to estimate the frequency and severity of such icing occurrences. The data were from the calendar year 2019 and included ~ 950,000 airline revenue flights from around the world by multiple operators. The unique architecture of the Primary Ice Detection System (PIDS) on that model, in addition to robust meteorological data that was able to be correlated, afforded an opportunity to conservatively estimate the Total Water Exposure (TWE) and thus the Liquid Water Content (LWC) of the icing encounters captured at FL295 and above. This paper will outline the key methods used and present the findings.
Sanford, JeromeBravin, MelissaClarkson, MatthewNatsui, Edward
Multiphase CFD simulations of air and water play a critical role in aircraft icing analysis. Specifically for air data sensors mounted near the front of an aircraft, simulations that predict the concentration of water surrounding an aircraft fuselage are necessary for understanding their performance in icing conditions. Those simulations can aid in sensor design and placement, and are central for defining critical conditions to test during icing qualification campaigns. There are several methods available in CFD that solve a multiphase flow field. Two of the most common methods used are Lagrangian and Eulerian. While these methods are similar, important differences can be viewed in the results, specifically in how the water shadow zones are predicted. This paper compares a Lagrangian and Eulerian CFD method for solving a multiphase flow field, and assesses their performance for use for analyzing installation locations and critical icing conditions of air data probes.
Thangavel, SathishCusher, Aaron
In 2017 the National Research Council of Canada developed an evaporation model for controlling engine icing tunnels in real time. The model included simplifications to allow it to update the control system once per second, including the assumption of sea level pressure in some calculations. Recently the engine icing system was required in an altitude facility requiring operation down to static temperatures of -40°C, and up to an altitude of 9.1 km (30 kft) or 30 kPa. To accommodate the larger temperature and pressure range the model was modified by removing the assumption of sea level operation and expanding the temperature range. In addition, due to the higher concentration of water vapor that can be held by the atmosphere at lower pressures, the significance of the effect of humidity on the air properties and the effect on the model was investigated. The effect of humidity on the density, specific heat, viscosity, thermal conductivity and Prandtl number of air compared to assuming dry air was examined. The effect of humidity on the individual thermodynamic and transport properties could be significant but the overall effect on the liquid water content calculated by the model to be delivered to the engine was not. The error in using the property correlations from the original model over the expanded temperature range was found to be minimal. Finally, the numerical technique was modified to decrease the solution time under extreme operating conditions. This modification increased the solution time in some standard conditions but still kept it within the required time. The new model was compared to the previous model under sea level conditions and found to give practically the same results within the expected error allowed by the solver.
Davison, Craig
Considerable amounts of water accumulate in aircraft fuel tanks due to condensation of vapor during flight or directly during fueling with contaminated kerosene. This can result in a misreading of the fuel meters. In certain aircraft types, ice blocks resulting from the low temperatures at high altitude flights or in winter time can even interfere with the nozzles of the fuel supply pipes from the tanks to the engines. Therefore, as part of the maintenance operations, water has to be drained in certain intervals ensuring that no remaining ice is present. In the absence of an established method for determining residual ice blocks inside, the aircraft operator has to wait long enough, in some cases too long, to start the draining procedure, leading potentially to an unnecessary long ground time. A promising technology to determine melting ice uses acoustic signals generated and emitted during ice melting. With acoustic emissions, mainly situated in the ultrasonic frequency range, a very high number of events can be recorded to characterize stress relaxation processes that occur during conversions from ice to water. In the present paper, in addition to the case of the fuel tank, the icing of a fuselage panel is also considered. The results obtained provide evidence that it is possible to determine the moment when all ice has melted. However, it is not possible to give exact figures on the amount of ice remaining or melted, which is not a limitation in practice.
Pfeiffer, HelgeReynaert, JohanSeveno, DavidJordaens, Pieter-JanCeyhan, OzlemWevers, Martine
This paper is focused on the numerical analysis of the impingement and water catch rate of snow particles on the engine air intake of the Next Generation Civil Tilt Rotor (NGCTR). This NGCTR is developed by Leonardo Helicopters. The collection efficiency and water catch rate for the intake geometry are obtained for the test cases that have been defined for the relevant snow conditions. These conditions are related to the flight envelope of the NGCTR, existing EASA/FAA certification specifications, and the snow characterization. The analyses have been performed for the baseline air intake geometry. A range of particle diameters has been simulated with a particle density equal to the density of ice and with a particle drag relation that disregards the particle shape. Based on the results for the water catch rate on the basic nacelle configuration in snow conditions it is concluded that the ‘cheeks’ of the duct are more susceptible to impingement of larger snow crystals (>75 μm), whereas the ‘chin’ of the duct is more susceptible to impingement of smaller droplets (<75 μm). Additionally, ground operations of the NGCTR are predicted not to be critical for icing by snow crystals primarily due to the perpendicular orientation of the intake plane to the rotor downwash. The assessment of the basic configuration of the NGCTR inlet in snow conditions has shown that the critical area of snow impact exists near the small passage inside the inlet where the duct transitions towards a circular shape.
Kool, NinaVan der Weide, EdwinSpek, Ferdinandvan der Ven, Harmenvan 't Hoff, Stefan
The prevailing mission-based paradigm for ocean color remote sensing typically involves high-cost satellite platforms launched and operated by government agencies such as NASA, NOAA, ESA, and JAXA. These platforms host state-of-the-art ocean-viewing radiometers with design and sensitivity specifications appropriate for delineating a comparatively weak water-leaving radiance from the total radiant signal detected at the top of the atmosphere. The current suite of such operational ocean color sensors includes NASA’s Moderate Resolution Imaging Spectroradi-ometer (MODIS; Aqua satellite), NOAA’s VIIRS (SNPP and NOAA-20 satellites), the Ocean and Land Color Instrument (OLCI; Sentinel-3 A/B satellites), and the Second-Generation Global Imager (SGLI) onboard the GCOM-C satellite. All of these sensors provide multi-spectral band sets (visible, near-infrared (NIR), and shortwave infrared (SWIR)) with daily coverage at approximately kilometer-scale spatial resolution. However, even kilometer-scale spatial resolution may be unable to resolve finer-scale features near rivers and estuaries that are critical for scientific and environmental resource management applications.
More than five million people in the United States live with some form of paralysis and may encounter difficulties completing everyday tasks, like grabbing a glass of water or putting on clothes. New research from Carnegie Mellon University’s Robotics Institute (RI) aims to increase autonomy for individuals with such motor impairments by introducing a head-worn device that will help them control a mobile manipulator.
Products for nautical applications face an unusual set of design challenges. The corrosiveness of salt water can cause premature degradation, and the impact of fast-moving vessels bouncing up against forceful ocean waves can also damage equipment.
In an automotive vehicle, the Window Regulator is an electro-mechanical assembly that is mounted inside the door. The basic function of the Window Regulator is to raise or lower the glass when required and hold the glass in closed position or in any desired position. During Water servicing or rains, Water will typically enter inside the door through the seals and on to the Window Regulator mechanism. Hence these conditions must be physically tested in the laboratory to assess the Window Regulator’s functionality which could get affected by Water intrusion. The Water spray test conditions are based on mutual agreement between Inteva Products and the OEMs. Water spray test involves moving the electric Window Regulator to upper stall position (Window closed) at a defined voltage and line resistance. The glass must be dwelled followed by spraying defined amount of Water which simulates the rain. The agreed number of test cycles would be around 4500 which lasts about 7 weeks. Hence, to prepare this test setup, a large area of floor space along with other testing peripherals were to be procured and this would involve good amount of space, cost, Water, and time. Hence the Test Lab team developed an economical in-house test setup using available resources and equipment to reuse and recycle which will lead to significant savings. This test setup developed to conduct Water spray test was carried out by using the available electric control box and mechanical infrastructure along with re-circulation of Water. The primary objective of this test setup was to comply with the test requirements along with Water reusage. This significantly reduced the new procurement / development cost and time since the available resources in the test lab were reused (80% of the materials were used from inventory, available in-house and from multipurpose devices and 20% were purchased).
Gavhane, SudarshanBabu, YugandharPrasannakumar, JitheshBanjan, Rohith
An automotive door latch that functions manually or electronically is a vital component of a door closure system. It primarily aims to provide security of the occupants by securing the door system by ensuring timely locking and unlocking of the doors. A wide range of factors like safety, ergonomics, and security influence the development of these latches to eliminate safety. With the growing trend and advancements, automotive electronics is becoming more complex and prevalent. Hence, any exposure of electrical/electronic components to water make them susceptible to short circuits, corrosion etc., thereby may make it the functionality of systems and increasing the chances of failure in these devices. Intrusion of water possible into the latch system can be disastrous depending on the climatic conditions. Stringent safety criteria have given rise to unconventional test methods that are time-consuming and hence necessitate virtual validation techniques. Virtual validation becomes a viable option and with proper correlation work it helps to address these types of problems at low cost and in early stages of product development The latch is subjected to an impact by a jet of water, modelled using Smoothened Particle Hydrodynamics (SPH) technique. SPH is a mesh-free method used to simulate fluid flow and has found its application in many engineering problems & fluid structure interaction (FSI) models. Since it can handle problems involving free surfaces, deformable boundaries, moving interfaces, extremely large deformation, and crack propagation, this was found to be an ideal technique for simulation. Water is made to impinge on the latch assembly and the/those water accumulated regions observed in the simulation were compared with the test results which are found to have good correlation. A design modification was suggested to prevent/minimize water ingression into the system which was further analyzed and proved to be efficient based on the FSI methodology.
Kaushik, AchalaKrishnamurthy, HarishGajendra, HarishCalamaco, Eli
A team of researchers at University of California, Riverside, has moved a step closer to finding a use for the hundreds of millions of tons of plastic waste produced every year that often winds up clogging streams and rivers and polluting our oceans.
The model-based design is very much prominent in the vehicle level control system design and state estimation algorithms. It gives the edge to understand and interpret the dynamic systems. Three-way catalytic converter is a thermo-chemical device to convert the toxic oxides into carbon dioxide and water vapor, during this conversion reactions it generates the heat over the catalyst surface. Detailed chemical and thermal model of the catalyst will be able to predict the conversion efficiency, state of stored oxygen (SoX) and oxygen storage capacity (OSC). As the catalyst get aged, the reaction rates of conversion reactions deteriorate, in results the temperature dynamics also varies which wanes the exothermic heat. In this work, a novel perspective is presented to capture the behavior of SoX and health of the catalytic converter using thermal model analysis of TWC. An equivalent second order multi input single output (MISO) linear sub-space model is identified for the complex detailed thermal model. A second order MISO system is obtained using measured temperature sensor signals across the device. Recursive least square method will be updating the system parameters online then Kalman filter is employed for state estimation. Joint estimation of the hidden state is tested and validated on urban drive cycle with differently aged catalytic converters.
Mandloi, DeepakSahu, PrachiBagade, Monika JayprakashDas, Himadri
The requirements of the automotive industry move along due to product competitiveness and this contributes to increase complexity in the requirements for evaluation. Simulation tools play a key role thanks to their versatility and multiple physical phenomena that can be represented. The axis of analysis for this paper is the problem of the interaction of airflow and water flow in the cowl/plenum/leaf screen components. Airflow is represented by HVAC system operating and water flow by the vehicle in torrential rain. Initially, one simulation is evaluated at a time, in one side, the airflow entering the HVAC system in which the amount of air entering is monitored and pressure drop, on the other, the water simulation on the vehicle, both using a Lagrangian CFD model (using with tools such as STAR CCM+® or Ansys Fluent®) Due to this, a CFD methodology was developed to evaluate the interaction of air and water flow. This uses CFD Eulerian model for airflow and a Lagrangian model for water, in which results from the initial simulation are included to evaluate the interaction of both fluids and consequently obtain a more significant result for water particle behavior. The research results show a significant change in the amount of water distribution in the system when it has airflow as an initial boundary condition. Furthermore, the kinematics of the windshield wipers is another key factor in the study, and it changes the physics of this analysis, which is currently under development to provide more effective results.
Alonso, LilianaSaavedra, OscarRuiz, Josias
Fuel cells are considered one of the promising technologies as possible replacement of Internal Combustion Engine (ICE) for the transportation sector due to their high efficiency, ultra-low (or zero) emissions and for the higher drive range. The Membrane Electrode Assembly (MEA) is what mainly influences the Fuel Cell FC performance, durability, and cost. In PEMFC the proton conductivity of the membrane is a function of the humidification level of the FC membrane, hence the importance of keeping the membrane properly humidified to achieve the best possible fuel cell performance. To have the optimal water content inside the fuel cell’s membrane several strategies could be adopted, dealing with the use of external device (such as membrane humidifier) or to adopt an optimal set of parameters (gas flow rate and temperature for example) to use the water produced at fuel cell cathode as humidity source. The aim of this paper is to study the behavior of a FC vehicle humidification system. Starting from experimental tests properly made with a commercial system, two different designs of the humidifier have been proposed. For both solutions, a CFD model has been developed to analyze the pressure drop and velocity. The membrane is modeled as a porous media to reduce the computational cost of the virtual CFD simulation. The simulation results have allowed to compare the two different proposed designs, performing a sensitivity analysis of the expected performances of the humidifier itself.
Carello, MassimilianaLandolfi, SilvioRizzello, AlessandroKhadilkar, Sumit
The development of perception functions for tomorrow’s automated vehicles is driven by enormous amounts of data: often exceeding a gigabyte per second and reaching into the terabytes per hour. Data is typically gathered by a fleet of dozens of mule vehicles which multiply the data generated into the hundreds of petabytes per year. Traditional methods for fueling data-driven development would record every bit of every second of a data logging drive on solid-state drives located on a PC in the vehicle. Recorded data must then be exported from these drives using an upload station which pushes to the data lake after arriving back at the garage. This paper considers different techniques for curating logged data. These curation methods are performed to maximize the usefulness of the data throughout its lifecycle and minimize the amount of data necessary for perception development and validation The reduction of logged data has the effect of not only curtailing storage costs, but also minimizing latency for data availability and maximizing possible campaign drive time. Advanced techniques considered include: (a) the real-time evaluation of sensor and bus signals, (b) the application of artificial intelligence (e.g. for similarity-based image discovery and dynamic scene content detection), and (c) using function prototyping to inform the data curation process. In addition, various possible integration points for the curation techniques are considered in the data ingestion pipeline - from the cloud in the datacenter to the in-vehicle logging system on the edge. The trade-offs for each proposed techniques are considered across the various components of the data ingestion pipeline to explore the feasibility of - and to arrive at some conclusions for - designing more intelligent data collection campaigns.
Perrin, JacobHasenklever, Daniel
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