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01413 Thermo-mechanical analysis of the ICRH antenna for the ignitor experiment. Part I: Faraday shield
14 Fuel science and technology (fuel cell technology) knowledge than the elementary limit analysis (plastic hinges, yield lines). Basic ideas of the approach are recalled and applied to slabs in one- and two-way bending, as well as to pressurized cylinders. The importance of the strength reserve due to the dome effect and the pertinence of the method are verified compared to the finite element simulation and to some tests on reinforced concrete models. The restrained bending response is very sensitive to 'secondary effects' (e.g. shape and support imperfections) that may strongly reduce the structure strength. The approximate method permits easily to account for initial deflections, imperfect contact and compliant supports.
06101413 Thermo-mechanical analysis of the ICRH antenna for the ignitor experiment, Part h Faraday shield Berruti, T. Fusion Engineering and Design, 2005, 73, (2 4), 155 169. The ion cyclotron resonance heating (ICRH) system of the ignitor machine has been designed. The description of one of the components of the ICRH system, the Faraday shield (FS), and all the relevant calculations are presented in this paper. The thermo-mechanical analysis of the FS is performed. The displacement and stresses due to thermal loads generated by the plasma and dynamic loads induced by plasma vertical disruptions events (VDE) are studied in detail taking into account different plasma scenarios. A final design of the FS that takes into account the theoretical and computational results obtained as well as the qualification for remote handling (RH) positioning of all the FS parts is proposed. A FS split into different compact and easily movable elements is presented.
06101414 Thermo-mechanical analysis of the ICRH antenna for the ignitor experiment, Part Ih Antenna straps Salvetti, M. F. et al. Fusion Engineering and Design, 2005, 73, (2 4), 171 180. This paper presents the design of the ion cyclotron resonance heating (ICRH) system of the ignitor machine. In addition, the paper presents relevant calculations and the design solutions adopted for the ICRH antenna straps. The thermal mechanical analysis of the structure is illustrated. The displacements and stresses due to thermal loading and to dynamic loads induced during plasma vertical disruptions events (VDE) are calculated. The capability of carrying out both the assembly and maintenance of the antennas' components in full remote handling (RH) conditions is one of the specifications to which the design has to comply. A mechanical design that guarantees ease of operation is discussed. The proposed solution minimizes the variety of movements required for the manipulator.
06101415
Transient modeling of micro-grooved heat pipe
Suman, B. et al. International Journal of Heat and Mass Transfer, 2005, 48, (8), 1633 1646. One-dimensional transient model for fluid flow and heat transfer is presented for a micro-grooved heat pipe of any polygonal shape utilizing a macroscopic approach. The coupled non-linear governing equations for the fluid flow, heat and mass transfer are developed based on first principles and are solved simultaneously. The transient behaviour for various parameters, e.g. substrate temperature, radius of curvature, liquid velocity, etc. are studied. The effects of the groove dimensions, heat input and Q-profiles on the studied parameters have been evaluated. The steady state profiles for substrate temperature, radius of curvature, liquid velocity etc. have also been generated. The model predicted steady state substrate temperature profile is successfully compared with the experimental results from the previous study. The general nature of the model and the associated parametric study ensure the wide applicability of the model.
06101416 Vibration tests on pile-group foundations using large-scale blast excitation Tanaka, H. et al. Nuclear Engineering and Design, 2005, 235, (17 19), 2087 2098. Extensive vibration tests have been performed on pile-supported structures at a large-scale mining site. Ground motions induced by large-scale blasting operations were used as excitation forces for vibration tests. The main objective of this research is to investigate the dynamic behaviour of pile-supported structures, in particular, pilegroup effects. Two test structures were constructed in an excavated 4 m deep pit. One structure had 25 steel tubular piles and the other had four piles. The super-structures were exactly the same. The test pit was backfilled with sand of appropriate grain size distributions in order to obtain good compaction, especially between the 25 piles. Accelerations were measured at the structures, in the test pit and in the adjacent free field, and pile strains were measured. The vibration tests were performed six times with different levels of input motions. The maximum horizontal acceleration recorded at the adjacent ground surface varied from 57 cm/s2 to 1683 cm/s2 according to the distances between the test site and the blast areas. Maximum strains were 13,400 micro-strains were recorded at the pile top of the four-pile structure, which means that these piles were subjected to yielding.
210
Fuel and Energy Abstracts
May 2006
06•01417 Wavelet time-frequency analysis of accelerating and decelerating flows in a tube bank Indrusiak, M. L. S. et al. Nuclear Engineering and Design, 2005, 235, (17 19), 1875 1887. In the present work, the steady approximation for accelerating and decelerating flows through tube banks is discussed. With this purpose, the experimental study of velocity and pressure fluctuations of transient turbulent cross-flow in a tube bank with square arrangement and a pitch-to-diameter ratio of 1.26 is performed. The Reynolds number at steady-state flow, computed with the tube diameter and the flow velocity in the narrow gap between the tubes, is 8 x 104. Air is the working fluid. The accelerating and decelerating transients are obtained by means of start and stop of the centrifugal blower. Wavelet and wavelet packet multi-resolution analysis were applied to decompose the signal in frequency intervals, using Daubechies 20 wavelet and scale functions, thus allowing the analysis of phenomena in a time frequency domain. The continuous wavelet transform was also applied, using the Morlet function. The signals in the steady state, which presented a bistable behaviour, were separated in two modes and analysed with usual statistic tools. The results were compared with the steady-state assumption, demonstrating the ability of wavelets for analysing time varying signals.
Fuel cell technology 06101418 A single-phase, non-isothermal model for PEM fuel cells Ju, H. et al. International Journal of Heat and Mass Transfer, 2005, 48, (7), 1303 1315. A proton exchange membrane (PEM) fuel cell produces a similar amount of waste heat to its electric power output, and tolerates a small temperature deviation from its design point for best performance and durability. These stringent thermal requirements present a significant heat transfer problem. In this work, a three-dimensional, nonisothermal model is developed to account rigorously for various heat generation mechanisms, including irreversible heat due to electrochemical reactions, entropic heat, and Joule heating arising from the electrolyte ionic resistance. The thermal model is further coupled with the electrochemical and mass transport models, thus permitting a comprehensive study of thermal and water management in PEM fuel cells. Numerical simulations reveal that the thermal effect on PEM fuel cells becomes more critical at higher current density and/or lower gas diffusion layer thermal conductivity. This three-dimensional model for single cells forms a theoretical foundation for thermal analysis of multicell stacks where thermal management and stack cooling is a significant engineering challenge.
06•01419 Conducting polymer-coated stainless steel bipolar plates for proton exchange membrane fuel cells (PEMFC) Joseph, S. et al. International Journal qf Hydrogen Energy, 2005, 30, (12), 1339 1344. Stainless steel satisfies many of the requirements for proton exchange membrane (PEM) fuel cell bipolar plates except its corrosion under fuel cell operating conditions. Metal oxide formation leads to contact resistance, and metal dissolution can cause contamination of the membrane electrode assembly (MEA). These problems can be solved by coating stainless steel plates with corrosion resistant and conductive layers. In this study, 304 stainless steel was coated electrochemically with the conducting polymers polyaniline (PANI) and polypyrrole (PPY). Cyclic voltammetry was used for the polymerisation and deposition of these polymers. The polymer-coated stainless steel plates were tested for corrosion and contact resistance under PEM fuel cell conditions, which showed improved corrosion resistance with acceptable contact resistance.
06•01420 Effects of geometric and electronic factors on ORR activity of carbon supported Pt-Co electrocatalysts in PEM fuel cells Antolini, E. et al. International Journal of Hydrogen Energy, 2005, 30, (11), 1213 1220. The effects of both geometric (Pt Pt bond distance) and electronic (Pt d-band vacancy) factors on the electrocatalytic activity for the oxygen reduction reaction (ORR) of carbon supported Pt and Pt Co alloy catalysts were investigated by X-ray diffraction and X-ray absorption spectroscopies in conjunction with electrochemical measurements in proton exchange membrane (PEM) fuel cells. In the presence of cobalt, a decrease in the Pt Pt bond distance and an increase in the metal particle size were observed. In PEM fuel cells the ORR activity on all the Pt Co/C catalysts was higher than that on Pt/C. A poor fit between the ORR activity and the P~Pt bond distance was found. Conversely,
06101413 Thermo-mechanical analysis of the ICRH antenna for the ignitor experiment, Part h Faraday shield Berruti, T. Fusion Engineering and Design, 2005, 73, (2 4), 155 169. The ion cyclotron resonance heating (ICRH) system of the ignitor machine has been designed. The description of one of the components of the ICRH system, the Faraday shield (FS), and all the relevant calculations are presented in this paper. The thermo-mechanical analysis of the FS is performed. The displacement and stresses due to thermal loads generated by the plasma and dynamic loads induced by plasma vertical disruptions events (VDE) are studied in detail taking into account different plasma scenarios. A final design of the FS that takes into account the theoretical and computational results obtained as well as the qualification for remote handling (RH) positioning of all the FS parts is proposed. A FS split into different compact and easily movable elements is presented.
06101414 Thermo-mechanical analysis of the ICRH antenna for the ignitor experiment, Part Ih Antenna straps Salvetti, M. F. et al. Fusion Engineering and Design, 2005, 73, (2 4), 171 180. This paper presents the design of the ion cyclotron resonance heating (ICRH) system of the ignitor machine. In addition, the paper presents relevant calculations and the design solutions adopted for the ICRH antenna straps. The thermal mechanical analysis of the structure is illustrated. The displacements and stresses due to thermal loading and to dynamic loads induced during plasma vertical disruptions events (VDE) are calculated. The capability of carrying out both the assembly and maintenance of the antennas' components in full remote handling (RH) conditions is one of the specifications to which the design has to comply. A mechanical design that guarantees ease of operation is discussed. The proposed solution minimizes the variety of movements required for the manipulator.
06101415
Transient modeling of micro-grooved heat pipe
Suman, B. et al. International Journal of Heat and Mass Transfer, 2005, 48, (8), 1633 1646. One-dimensional transient model for fluid flow and heat transfer is presented for a micro-grooved heat pipe of any polygonal shape utilizing a macroscopic approach. The coupled non-linear governing equations for the fluid flow, heat and mass transfer are developed based on first principles and are solved simultaneously. The transient behaviour for various parameters, e.g. substrate temperature, radius of curvature, liquid velocity, etc. are studied. The effects of the groove dimensions, heat input and Q-profiles on the studied parameters have been evaluated. The steady state profiles for substrate temperature, radius of curvature, liquid velocity etc. have also been generated. The model predicted steady state substrate temperature profile is successfully compared with the experimental results from the previous study. The general nature of the model and the associated parametric study ensure the wide applicability of the model.
06101416 Vibration tests on pile-group foundations using large-scale blast excitation Tanaka, H. et al. Nuclear Engineering and Design, 2005, 235, (17 19), 2087 2098. Extensive vibration tests have been performed on pile-supported structures at a large-scale mining site. Ground motions induced by large-scale blasting operations were used as excitation forces for vibration tests. The main objective of this research is to investigate the dynamic behaviour of pile-supported structures, in particular, pilegroup effects. Two test structures were constructed in an excavated 4 m deep pit. One structure had 25 steel tubular piles and the other had four piles. The super-structures were exactly the same. The test pit was backfilled with sand of appropriate grain size distributions in order to obtain good compaction, especially between the 25 piles. Accelerations were measured at the structures, in the test pit and in the adjacent free field, and pile strains were measured. The vibration tests were performed six times with different levels of input motions. The maximum horizontal acceleration recorded at the adjacent ground surface varied from 57 cm/s2 to 1683 cm/s2 according to the distances between the test site and the blast areas. Maximum strains were 13,400 micro-strains were recorded at the pile top of the four-pile structure, which means that these piles were subjected to yielding.
210
Fuel and Energy Abstracts
May 2006
06•01417 Wavelet time-frequency analysis of accelerating and decelerating flows in a tube bank Indrusiak, M. L. S. et al. Nuclear Engineering and Design, 2005, 235, (17 19), 1875 1887. In the present work, the steady approximation for accelerating and decelerating flows through tube banks is discussed. With this purpose, the experimental study of velocity and pressure fluctuations of transient turbulent cross-flow in a tube bank with square arrangement and a pitch-to-diameter ratio of 1.26 is performed. The Reynolds number at steady-state flow, computed with the tube diameter and the flow velocity in the narrow gap between the tubes, is 8 x 104. Air is the working fluid. The accelerating and decelerating transients are obtained by means of start and stop of the centrifugal blower. Wavelet and wavelet packet multi-resolution analysis were applied to decompose the signal in frequency intervals, using Daubechies 20 wavelet and scale functions, thus allowing the analysis of phenomena in a time frequency domain. The continuous wavelet transform was also applied, using the Morlet function. The signals in the steady state, which presented a bistable behaviour, were separated in two modes and analysed with usual statistic tools. The results were compared with the steady-state assumption, demonstrating the ability of wavelets for analysing time varying signals.
Fuel cell technology 06101418 A single-phase, non-isothermal model for PEM fuel cells Ju, H. et al. International Journal of Heat and Mass Transfer, 2005, 48, (7), 1303 1315. A proton exchange membrane (PEM) fuel cell produces a similar amount of waste heat to its electric power output, and tolerates a small temperature deviation from its design point for best performance and durability. These stringent thermal requirements present a significant heat transfer problem. In this work, a three-dimensional, nonisothermal model is developed to account rigorously for various heat generation mechanisms, including irreversible heat due to electrochemical reactions, entropic heat, and Joule heating arising from the electrolyte ionic resistance. The thermal model is further coupled with the electrochemical and mass transport models, thus permitting a comprehensive study of thermal and water management in PEM fuel cells. Numerical simulations reveal that the thermal effect on PEM fuel cells becomes more critical at higher current density and/or lower gas diffusion layer thermal conductivity. This three-dimensional model for single cells forms a theoretical foundation for thermal analysis of multicell stacks where thermal management and stack cooling is a significant engineering challenge.
06•01419 Conducting polymer-coated stainless steel bipolar plates for proton exchange membrane fuel cells (PEMFC) Joseph, S. et al. International Journal qf Hydrogen Energy, 2005, 30, (12), 1339 1344. Stainless steel satisfies many of the requirements for proton exchange membrane (PEM) fuel cell bipolar plates except its corrosion under fuel cell operating conditions. Metal oxide formation leads to contact resistance, and metal dissolution can cause contamination of the membrane electrode assembly (MEA). These problems can be solved by coating stainless steel plates with corrosion resistant and conductive layers. In this study, 304 stainless steel was coated electrochemically with the conducting polymers polyaniline (PANI) and polypyrrole (PPY). Cyclic voltammetry was used for the polymerisation and deposition of these polymers. The polymer-coated stainless steel plates were tested for corrosion and contact resistance under PEM fuel cell conditions, which showed improved corrosion resistance with acceptable contact resistance.
06•01420 Effects of geometric and electronic factors on ORR activity of carbon supported Pt-Co electrocatalysts in PEM fuel cells Antolini, E. et al. International Journal of Hydrogen Energy, 2005, 30, (11), 1213 1220. The effects of both geometric (Pt Pt bond distance) and electronic (Pt d-band vacancy) factors on the electrocatalytic activity for the oxygen reduction reaction (ORR) of carbon supported Pt and Pt Co alloy catalysts were investigated by X-ray diffraction and X-ray absorption spectroscopies in conjunction with electrochemical measurements in proton exchange membrane (PEM) fuel cells. In the presence of cobalt, a decrease in the Pt Pt bond distance and an increase in the metal particle size were observed. In PEM fuel cells the ORR activity on all the Pt Co/C catalysts was higher than that on Pt/C. A poor fit between the ORR activity and the P~Pt bond distance was found. Conversely,