The Experts below are selected from a list of 52884 Experts worldwide ranked by ideXlab platform
V Vasechko - One of the best experts on this subject based on the ideXlab platform.
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performance of different tungsten grades under transient Thermal Loads
Nuclear Fusion, 2011Co-Authors: J Linke, Thorsten Loewenhoff, V Massaut, G Pintsuk, G Ritz, M Rodig, A Schmidt, C Thomser, I Uytdenhouwen, V VasechkoAbstract:Plasma facing components in future thermonuclear fusion devices will be subjected to intense transient Thermal Loads due to type I edge localized modes (ELMs), plasma disruptions, etc. To exclude irreversible damage to the divertor targets, local energy deposition must remain below the damage threshold for the selected wall materials. For monolithic tungsten (pure tungsten and tungsten alloys) power densities above ?0.3?GW?m?2 with 1?ms duration result in the formation of a dense crack network. Thin tungsten coatings for the so-called ITER-like wall in JET, which have been deposited on a two-directional carbon?fibre composite (CFC) material, are even less resistant to Thermal shock damage; here the threshold values are by a factor of 2 lower. First ELM-simulation experiments with high cycle numbers up to 104 cycles on actively cooled bulk tungsten targets do not reveal any cracks for absorbed power densities up to 0.2?GW?m?2 and ELM-durations in the sub-millisecond range (0.8?ms); at somewhat higher power densities (0.27?GW?m?2, ?t = 0.5?ms) cracks have been detected for 106 cycles.
Hasan Mehrjerdi - One of the best experts on this subject based on the ideXlab platform.
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hybrid hydrogen battery storage to smooth solar energy volatility and energy arbitrage considering uncertain electrical Thermal Loads
Renewable Energy, 2020Co-Authors: Reza Hemmati, Hasan Mehrjerdi, Mosayeb BornapourAbstract:Abstract This paper brings together the benefits of hydrogen and battery storage devices in the electrical network integrated with solar energy. The introduced hybrid storage system is utilized to achieve two purposes including uncertainty leveling and energy arbitrage. The volatility of solar energy and electrical-Thermal Loads is developed by Normal distribution. The hydrogen storage system is designed to smooth such uncertainty and storing the electrical energy in hydrogen form. Therefore, the hydrogen storage levels the uncertainties associated with solar power and Loads. The battery is utilized to shift energy from pricey hours to the inexpensive time intervals and minimizing energy cost in network. The optimization programming finds optimal setting and charging-discharging pattern for both storage technologies. The seasonal profile is considered for electrical-Thermal Loads and solar energy. It is verified that the given hybrid storage scheme saves the cost by 117000 $/year and the solar system decreases the cost by 28%.
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Optimal cooperation of a hydrogen storage system and fuel cell to supply electrical and Thermal Loads
Journal of Renewable and Sustainable Energy, 2019Co-Authors: Hasan MehrjerdiAbstract:A framework is planned to supply electrical and Thermal Loads by joint application of a hydrogen storage system (HSS) and a fuel cell. The system, including electrical and Thermal Loads, is connect...
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Optimal cooperation of a hydrogen storage system and fuel cell to supply electrical and Thermal Loads
Journal of Renewable and Sustainable Energy, 2019Co-Authors: Hasan MehrjerdiAbstract:A framework is planned to supply electrical and Thermal Loads by joint application of a hydrogen storage system (HSS) and a fuel cell. The system, including electrical and Thermal Loads, is connected to the upstream network. The bidirectional operation is defined for the system, and the system can buy energy from the grid or sell energy to the grid. A water electrolyzer is applied to produce hydrogen from water and store electricity in the form of hydrogen. The stored hydrogen supplies the Thermal Loads, as well as the fuel cell. The electrical Loads are directly connected to the grid and are supplied by the grid. The electricity is received from the fuel cell at hours 17 to 22. When the price of electricity is high, the electrical Loads can receive their power from the fuel cell rather than the grid. Additionally, any excess electricity may be sold to the grid. The uncertainty in the Thermal and electrical Loads is modeled and formulated as stochastic programming. The hydrogen is fed to the fuel cell and the Thermal Loads. The proposed model minimizes the daily operational cost of the system. The results demonstrate that the daily operational cost of the system is $22.274 USD/day. The bidirectional operation reduces the daily operational cost by about 79%. The unceratinty increases the cost by about 15%.A framework is planned to supply electrical and Thermal Loads by joint application of a hydrogen storage system (HSS) and a fuel cell. The system, including electrical and Thermal Loads, is connected to the upstream network. The bidirectional operation is defined for the system, and the system can buy energy from the grid or sell energy to the grid. A water electrolyzer is applied to produce hydrogen from water and store electricity in the form of hydrogen. The stored hydrogen supplies the Thermal Loads, as well as the fuel cell. The electrical Loads are directly connected to the grid and are supplied by the grid. The electricity is received from the fuel cell at hours 17 to 22. When the price of electricity is high, the electrical Loads can receive their power from the fuel cell rather than the grid. Additionally, any excess electricity may be sold to the grid. The uncertainty in the Thermal and electrical Loads is modeled and formulated as stochastic programming. The hydrogen is fed to the fuel cell and...
Jihwan Kim - One of the best experts on this subject based on the ideXlab platform.
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structural stability of functionally graded panels subjected to aero Thermal Loads
Composite Structures, 2008Co-Authors: K J Sohn, Jihwan KimAbstract:Abstract Static and dynamic stabilities of functionally graded (FG) panels which are subjected to combined Thermal and aerodynamic Loads are investigated. The volume fractions of constituent materials composing the FG panels are assumed to be given by a simple power law distribution. Material properties of the FG panels are obtained by a linear rule of mixture. Panels are considered as rectangular plates which are based on the first-order shear deformation theory. The von Karman strain–displacement relation is used to account for geometric nonlinearity, which is caused by a large deformation. The first-order piston theory is used to simulate supersonic aerodynamic Loads acting on the panels. Equations of motion are derived by the principle of virtual work and numerical solutions are obtained by a finite element method. The Newton–Raphson method is applied to get solutions of the nonlinear governing equations. Flutter boundaries are defined by linear flutter analysis and the Guyan reduction is applied to reduce degree of freedom for eigenvalue analysis. The influence of the material constitution, asymmetric characteristics of FG panels on Thermal buckling and flutter characteristics are examined. Static and dynamic stability margins of FG panels are defined for various volume fractions.
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nonlinear bending response of functionally graded plates under Thermal Loads
Journal of Thermal Stresses, 2006Co-Authors: Jihwan KimAbstract:ABSTRACT Nonlinear bending analysis of functionally graded plates subjected to uniform pressure and Thermal Loads is investigated using a 3-D finite element method. Material properties are varied continuously in the thickness direction according to a simple power law distribution. A three-dimensional solid element is used for more accurate modeling of material properties and temperature field in the thickness direction. The Green–Lagrange nonlinear strain-displacement relation is used to account for large deflection due to uniform pressure and Thermal Loads and the incremental formulation is applied for nonlinear analysis. The Thermal Loads are assumed as uniform, linear and sinusoidal temperature rises across the thickness direction. In numerical studies, the nonlinear bending responses of Al2O3-Ni FGM plates due to temperature field, volume fraction distribution, and system geometric parameters are presented, in detail.
Suhail Albhaisi - One of the best experts on this subject based on the ideXlab platform.
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effect of substructure stiffness on performance of steel integral abutment bridges under Thermal Loads
Transportation Research Record, 2012Co-Authors: Suhail Albhaisi, Hani Nassif, Euiseung HwangAbstract:This paper presents a study that investigated the effect of substructure stiffness on the performance of short- and medium-length steel integral abutment bridges (IABs) built on clay under Thermal load effects. Various parameters, such as pile size and orientation, pile type, and foundation soil stiffness, were considered in the study. Detailed, three-dimensional (3-D), finite element (FE) models were developed to capture the behavior of IABs. Field measurements from a IAB were used to validate the 3-D FE model developed with LUSAS software. With the use of validated models, a parametric study was carried out to study the effect of these parameters on the performance of IABs under Thermal loading with AASHTO load and resistance factor design temperature ranges. The study showed that the substructure stiffness had a significant effect on the stress level induced by Thermal Loads in various components of the substructure and superstructure. The results also showed significant variations in displacement and ...
J Linke - One of the best experts on this subject based on the ideXlab platform.
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performance of different tungsten grades under transient Thermal Loads
Nuclear Fusion, 2011Co-Authors: J Linke, Thorsten Loewenhoff, V Massaut, G Pintsuk, G Ritz, M Rodig, A Schmidt, C Thomser, I Uytdenhouwen, V VasechkoAbstract:Plasma facing components in future thermonuclear fusion devices will be subjected to intense transient Thermal Loads due to type I edge localized modes (ELMs), plasma disruptions, etc. To exclude irreversible damage to the divertor targets, local energy deposition must remain below the damage threshold for the selected wall materials. For monolithic tungsten (pure tungsten and tungsten alloys) power densities above ?0.3?GW?m?2 with 1?ms duration result in the formation of a dense crack network. Thin tungsten coatings for the so-called ITER-like wall in JET, which have been deposited on a two-directional carbon?fibre composite (CFC) material, are even less resistant to Thermal shock damage; here the threshold values are by a factor of 2 lower. First ELM-simulation experiments with high cycle numbers up to 104 cycles on actively cooled bulk tungsten targets do not reveal any cracks for absorbed power densities up to 0.2?GW?m?2 and ELM-durations in the sub-millisecond range (0.8?ms); at somewhat higher power densities (0.27?GW?m?2, ?t = 0.5?ms) cracks have been detected for 106 cycles.
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failure modes of vacuum plasma spray tungsten coating created on carbon fibre composites under Thermal Loads
Journal of Nuclear Materials, 2009Co-Authors: T Hirai, N Bekris, J P Coad, C Grisolia, J Linke, H Maier, G F Matthews, V Philipps, E WesselAbstract:Abstract Vacuum plasma spray tungsten (VPS-W) coating created on a carbon fibre reinforced composite (CFC) was tested under two Thermal load schemes in the electron beam facility to examine the operation limits and failure modes. In cyclic ELM-like short transient Thermal Loads, the VPS-W coating was destroyed sub-layer by sub-layer at 0.33 GW/m 2 for 1 ms pulse duration. At longer single pulses, simulating steady-state Thermal Loads, the coating was destroyed at surface temperatures above 2700 °C by melting of the rhenium containing multilayer at the interface between VPS-W and CFC. The operation limits and failure modes of the VPS-W coating in the Thermal load schemes are discussed in detail.
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post examination of helium cooled tungsten components exposed to demo specific cyclic Thermal Loads
Symposium On Fusion Technology, 2009Co-Authors: G Ritz, T Hirai, J Linke, P Norajitra, R Giniyatulin, Lorenz SingheiserAbstract:Abstract A concept of helium-cooled tungsten finger module was developed for the European DEMO divertor. The concept was realized and tested under DEMO specific cyclic Thermal Loads up to 10 MW/m2. The modules were examined carefully before and after loading by metallography and microstructural analyses. While before loading mainly discrete and shallow cracks were found on the tungsten surface due to the manufacturing process, dense crack networks were observed at the loaded surfaces due to the Thermal stress. In addition, cracks occurred in the structural, heat sink part and propagated along the grains orientation of the deformed tungsten material. Facilitated by cracking, the molten brazing metal between the tungsten plasma facing material and the W–La2O3 heat sink, that could not withstand the operational temperatures, infiltrated the tungsten components and, due to capillary forces, even reached the plasma facing surface through the cracks. The formed cavity in the brazed layer reduced the heat conduction and the modules were further damaged due to overheating during the applied heat Loads. Based on this detailed characterization and possible improvements of the design and of the manufacturing routes are discussed.
