119 research outputs found
Damage mechanism characterization of ±35° and ±55° FW composite tubes using acoustic emission method
No full textThe focus of this study is to investigate the mechanical properties, of ±35° and ±55° filament wound (FW) composite tubes under axial compression loading using the acoustic emission technique. For this purpose, material failure, crashworthiness characteristics, and the effect of each mechanism on the energy absorption capacity were studied using numerical and experimental approaches. Also, to identify and estimate the contribution percentage of damage mechanisms as well as how the damage grows in the specimens, the analysis of acoustic emission signals recorded during loading was performed. Digital image correlation was additionally used to capture displacement/strain contour maps. Finally, to analyze the effect of the winding pattern in the experimental test, the tubes were simulated using finite element analysis (FEA). For modeling of damage mechanisms, a 3D continuum damage model was used. The results of signal processing showed that by increasing the weaving angle of fibers from ±35° to ±55°, the separation of fibers from the matrix decreases, and the percentage of matrix crushing and fiber failure increases. The assessment of damage percentages showed that the reason for the large drop in force at ±55° compared to ±35° is the increase in matrix crushing. Furthermore, the failure behavior of FW tubes appeared to be dominated by local buckling, and the FEA effectively predicted the linear behavior and maximum load value of the composite tubes.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Ship Hydromechanics and Structure
Noise simulations on an airfoil with trailing-edge serrations: Validation of a hybrid RANS/LES approach
No full textA hybrid Reynolds Averaged Navier Stokes (RANS)/Large Eddy Simulation (LES) approach to predict airfoils with Trailing-Edge Serrations (TES) both, aerodynamically and aeroacoustically, is validated using experimental results on trailing–-edge noise from a NACA 633–018 airfoil for a chord–-based Reynolds Number (Re) of 3, 9 × 104. It was experimentally analyzed in the TU Delft wind tunnel, where aerodynamic and acoustic data was collected in the anechoic test section. A highly automated process chain was developed to assess the aerodynamic performance of serrated blade sections, develop efficient wind tunnel tests, and support design questions during the development process. The process comprises the parametrization and meshing of the blade sections, performs the simulations, and conducts the post–processing of the results. A standard Unsteady Reynolds Averaged Navier Stokes (URANS) approach was utilized for purely aerodynamic investigations, whereas an embeddedLES approach was used to predict the aeroacoustics of the airfoil. Therein, synthetic turbulence being injected in the mid–chord region of the airfoil is propagated to the trailing–edge within a wall–modeled LES subdomain. The far–field noise is evaluated employing the Ffowcs-Williams and Hawkings (FW-H) acoustic analogy by placing the evaluation surface on the airfoil’s solid boundary. The aerodynamic characteristics, boundary layer parameters, far–field trailing–edge noise from the baseline airfoil with a straight trailing–edge and trailing–edge serrations are investigated. Detailed aerodynamic analyzes focusing on the effect of different parameters on the aerodynamics as well as a thorough aeroacoustic evaluation will be shown in the full thesis.Aerospace Engineerin
Life-cycle assessment of water injection into hydrocarbon reservoirs using exergy concept
No full textWater injection into hydrocarbon reservoirs has been studied in great detail both from the subsurface and from surface perspectives, usually aiming at maximizing the production of low-cost oil. Here, the exergy concept is used to examine the potential life-cycle impact of injecting water into hydrocarbon reservoirs by considering the energy requirements of the process. It is found that the exergy recovery factor, being the ratio between the produced exergy corrected for material and process exergy requirements for its extraction and the gross exergy of the source decreases with time. Usually the process exergy requirements to produce the exergy increases with time. In the case of water injection the main contributors to the process exergy are due to treatment of water and the pumping of reservoir fluids. The method presented in this paper can also quantify the amount of CO2 per unit volume of the produced oil. It is contended that the volume of water required to produce the oil is an important indicator of the efficiency of water drive recovery of oil. Moreover, the amount of carbon dioxide produced for the extraction of one barrel of oil depends strongly on the water cut fw.in the producers. Below fw = 80% little CO2 is produced; however, when fw> 90% a small increase in the water cut leads to a large increase of carbon dioxide production. This emphasizes the importance of water management in water drive recovery of oil.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Reservoir Engineerin
Food Waste through the Food-Water-Energy Nexus Lenses: A Case Study of Amsterdam
No full textFood waste is a global issue that causes various but significant global impacts, wasting millions of hectares of arable land, 0.75 to 1.25 trillion of cubic meter of water per year, and about 1.5% of the global energy production. In developed nations, food waste occurs mainly at the retail and consumer stage. By 2050, 80% of the global food consumption will take place within cities. Cities are also a key nexus of energy, water, and food flows. Amsterdam offers an interesting case study as the city does not have any comprehensive strategy to tackle the food waste produced within its boundaries. Yet, the city has shown ambitions in transforming itself into a sustainable metropolis with strong renewable energy and circular strategies. This study uses the Food-Energy-Water (FEW) Nexus approach, particularly suited to understand the interactions and interconnections between Amsterdam’s food flows and the energy and water systems. This study performs a Material Flow Analysis to quantify the different food waste (FW) flows and their origins. It finds that households are the main producers of food waste compared to FW-producing businesses in Amsterdam. Bread, dairy, vegetables, and fruits are the largest avoidable FW, while vegetable peels, fruits peels, coffee grounds, and potatoes peels constitute the bulk of unavoidable food waste. It then quantifies the embedded energy and water present within these food flows. Using the latest developments in the field of bio-based economy regarding food waste valorization, it provides an inventory of the potential technologies available to valorize Amsterdam’s FW. The study then quantifies the energy and water inputs of 12 of these food waste-valorizing technologies. This step confirms the large knowledge gap regarding the water and energy intensities of the latest bio-based technologies. The type and amount of recovered resources through these technologies are also quantified. In addition, this study provides a review of the current social and commercial initiatives based in Amsterdam tackling this issue of food waste. It offers a six-category qualitative framework to assess their food waste rescue potential. Then, a new food waste management and valorization framework is proposed, based on the Value Pyramid model from the bio-based economy, the Food Waste Management Hierarchy framework, and the FEW nexus insights developed in this study. This new framework enables to outline strategies for both Amsterdam’s avoidable and unavoidable food waste flows. It suggests anaerobic digestion, Black Soldier Fly bioconversion, and composting as potential FEW-efficient solutions for Amsterdam’s unavoidable FW. Last, Amsterdam’s FW stakeholders are analyzed through their importance, interests, and potential roles in a future FW scheme. It suggests that the municipality and AEB, Amsterdam’s Waste-to-Energy plant should be at the center of a future FW valorization scheme. Overall, this study combines the FEW nexus perspective and the bio-based economy approach to identify the best options to manage and valorize Amsterdam’s food waste.Industrial Ecolog
High-value food waste valorisation in the Amsterdam Metropolitan Area: A combined environmental-, socio-technical- and network analysis of anaerobic fermentation technologies for fatty acids production, from a nexus governance perspective
No full textThe unprecedented major scale and rapid rate of urban growth put an increasing pressure on natural resources for providing energy, materials, and food- and nutrition security. Likewise, an alarming major increase can be witnessed in the generation of food waste (FW) in urban areas. While megacities contribute to 6.7% of the global population, 12.6% of global waste disposal can be attributed to them1. 30 to 50% of produced food is never consumed, and FW constitutes 25 to 30% of municipal solid waste in high-income countries which is expected to grow 35% until 20252. One of these high-income, highly urbanized areas is the Amsterdam Metropolitan Area (AMA), where the related impacts of FW treatment create important environmental and socio-economic challenges that demand optimisation in terms of reduced environmental impacts and enhanced resource recovery. The AMA poses an interesting case study with high ambitions for a circular economy in relation to organic and biobased resources, yet a comprehensive regional strategy for circular and sustainable FW waste treatment remains uncomposed, while effective FW prevention does not emerge. Especially with regard to techniques that obtain more high-value, circular products as aimed for by the Dutch government. Only few studies investigate these high-value techniques, and more importantly lack to demonstrate the role of governance in the socio-technical transition that is required, and the impact it has on the main actors in the current system, as it requires a change from a systems perspective. Therefore, this research applies a two-dimensional nexus governance approach specific to the context of three high-value valorisation techniques in the AMA that use fermentation technologies for fatty acids production (i.e. Chaincraft for feed additives, Amsterdam Green Campus for food additives, and the FABULOUS-project for bioplastics). It investigates how these technologies could contribute to more circular and sustainable FW valorisation. This is respectively analysed by means of a socio-technical analysis and social network analysis, including a baseline study of available FW flows and an environmental assessment (EA) of the investigated technologies.Industrial Ecolog
Investigation of energy absorption capacity of 3D filament wound composite tubes: experimental evaluation, numerical simulation, and acoustic emission monitoring
No full textBy analyzing the failure mechanisms, crashworthiness characteristics of FW composite tubes subjected to two modes of progressive damage and catastrophic failure are investigated using acoustic emission technique and numerical method. The AE signals of ±45° composite tubes were classified using hierarchical and wavelet transform methods, and based on the realistic and three-dimensional geometrical architecture of tubular structures, the microstructural finite element model was developed using Catia and ABAQUS software. Then deformation patterns and the impression of each mechanism on the crashworthiness characteristics were assessed. Results indicated that fiber breakage and fiber/matrix debonding could likely control the higher percentage of damage. By changing the type of modes from progressive damage to catastrophic failure, the percentage of matrix cracking increases, the fiber/matrix separation decreases, and the failure behavior become dominated by local buckling. Comparing the FE simulation with experimental results, we found the proposed 3D model can reasonably predict the pre-crushing, post-crushing, and material densification.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Ship Hydromechanics and Structure
Computational aeroacoustics of rotor noise in novel aircraft configurations: A lattice-boltzmann method-based study
No full textThe accurate and reliable prediction of the aerodynamic noise sources of open rotors and ducted-fans in electric Vertical Take-Off and Landing (eVTOL) and non-conventional aircraft configurations is a challenging task from a computational perspective. Indeed, such propulsive systems can often operate in highly distorted and non-homogeneous flows, with the rotating blades interacting with strongly non-uniform and turbulent flows; and/or experience phenomena related to low Reynolds numbers and boundary-layer transition, due to the relatively small diameters and blade tip speeds. While analytical, semi-empirical and low-fidelity numerical models can provide quick and computationally inexpensive predictions, their results are often not fully reliable and their state-of-the-art requires a further development step to properly address the problem of rotor noise prediction in non-conventional aircraft and rotorcraft. On the other hand, Navier-Stokes based scale-resolving approaches such as Large Eddy Simulation (LES) have the capability to capture most of the aforementioned phenomena, but at a prohibitive computational cost for a routine employment in the design stages of such innovative vehicles. In view of this, high-fidelity scale-resolving lattice-Boltzmann (LB) numerical simulations, coupled with the Ffowcs Williams & Hawkings' (FW-H) acoustic analogy, are extensively performed and validated in this thesis. A wide range of aeroacoustic problems, spanning from airfoil and small-scale propellers in transitional boundary-layer regime to open rotors in blade-vortex interaction conditions and ducted fans ingesting the airframe turbulent boundary-layer, are addressed with the aim of predicting, identifying and characterizing and the primary sources of aerodynamic noise associated to open rotors/propellers and ducted-fans in eVTOL and novel aircraft configurations by means of the hybrid LB/FW-H approach.Wind Energ
A Hybrid Magnetic Current Sensor With a Multiplexed Ripple-Reduction Loop
No full textThis article presents a hybrid magnetic current sensor for galvanically isolated measurements. It consists of a CMOS chip that senses the magnetic field generated by current flowing through a lead-frame-based current rail. Hall plates and coils are used to sense low-frequency (dc to 10 kHz) and high-frequency (10 kHz to 5 MHz) magnetic fields, respectively. With the help of on- chip calibration coils, the biasing current of the Hall plates is trimmed to match the sensitivity of the Hall and coil signal paths. The sensitivity drift of the coil path with temperature is compensated by using temperature-dependent gain-setting resistors, while the drift of the Hall path is compensated by biasing the Hall plates with a proportional- to-absolute-temperature (PTAT) current. The resulting sensitivity drift is less than 9% from-40 °C to 80 °C. The offset of the Hall plates is reduced by the current spinning technique, and the resulting ripple is suppressed by a multiplexed ripple-reduction loop (MMRL). Fabricated in a standard 0.18-μm CMOS process, the current sensor occupies 4.6 mm2 and draws 7.8 mA from a 1.8-V supply. It achieves a gain variation of only ±2% in a 5-MHz BW. It also achieves high energy efficiency, with an figure of merit (FoM) of 1.6 fW/Hz.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic
Consumer preferences in the design of airport passenger areas
No full textIn recent decades, commercial developments have become increasingly important for the overall profit of airports. However, little is known about consumer preferences regarding the design of passenger areas, which is striking as the design of terminal buildings affects consumers' emotional state and shopping behaviour. The aim of this study was therefore to investigate how architectural design characteristics are valued by airport passengers, using visualizations of hypothetical passenger areas. Discrete choice experiments were used to investigate passenger preferences for eight design characteristics. Data on 346 passengers were collected in June 2008 in departure and transfer areas at Amsterdam Airport Schiphol. Analyses showed that passengers preferred a passenger area with a curvilinear roof, a curved layout, the presence of greenery, no decoration reflecting the distinctiveness of Holland, warm lighting, wide dimensions and white materials. Signage had no influence.Real Estate & HousingArchitecture and The Built Environmen
The role of water models on the prediction of slip length of water in graphene nanochannels
No full textSlip lengths reported from molecular dynamics (MD) simulations of water flow in graphene nanochannels show significant scatter in the literature. These discrepancies are in part due to the used water models. We demonstrate self-consistent comparisons of slip characteristics between the SPC, SPC/E, SPC/Fw, TIP3P, TIP4P, and TIP4P/2005 water models. The slip lengths are inferred using an analytical model that employs the shear viscosity of water and channel average velocities obtained from nonequilibrium MD simulations. First, viscosities for each water model are quantified using MD simulations of counterflowing, force-driven flows in periodic domains in the absence of physical walls. While the TIP4P/2005 model predicts water viscosity at the specified thermodynamic state with 1.7% error, the predictions of SPC/Fw and SPC/E models exhibit 13.9% and 23.1% deviations, respectively. Water viscosities obtained from SPC, TIP4P, and TIP3P models show larger deviations. Next, force-driven water flows in rigid (cold) and thermally vibrating (thermal) graphene nanochannels are simulated, resulting in pluglike velocity profiles. Large differences in the flow velocities are observed depending on the used water model and to a lesser extent on the choice of rigid vs thermal walls. Depending on the water model, the slip length of water on cold graphene walls varied between 34.2 nm and 62.9 nm, while the slip lengths of water on thermal graphene walls varied in the range of 38.1 nm-84.3 nm.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Engineering ThermodynamicsComplex Fluid Processin
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