The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform
A G Olabi - One of the best experts on this subject based on the ideXlab platform.
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a comprehensive study of the effect of bipolar Plate bp Geometry design on the performance of proton exchange membrane pem fuel cells
Renewable & Sustainable Energy Reviews, 2019Co-Authors: Tabbi Wilberforce, Zaki El Hassan, Emmanuel Ogungbemi, Oluwatosin Ijaodola, F N Khatib, A Durrant, James Thompson, Ahmad Baroutaji, A G OlabiAbstract:Abstract Fuel cell efficiency is determined by many factors, including operational parameters such as electrochemical kinetics, cell operating temperature, mass transport, flow rates and other physical components in the cell stack like the membrane electrode assembly (MEA) as well as the bipolar Plate (BP). The BP accounts for almost 70% of the mass of the stack and 30% of the overall price of the cell stack on the fuel cell market. The bipolar Plate Geometry design serves as the medium of entry of the reactive gases into the fuel cell and also functions as a platform for easy dissemination of the reactive substance onto the active surface of the cell stack. Its crucial role in the stack determines water management for the PEM fuel cell, thermal and electrical conductivity, mass transport and current density distribution. This research therefore aims to make a critical assessment of existing bipolar Plate Geometry design with respect to the maximum functionality of fuel cell (advantages and disadvantages of each design considered). The work thoroughly discusses some parameters that define an effective bipolar Plate Geometry design which is able to enhance the functionality of a cell stack. Furthermore, the work will serve as a guide to the fuel cell research community in the selection of a suitable Geometry design for any fuel cell operating at varying conditions.
S V Taskaev - One of the best experts on this subject based on the ideXlab platform.
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plastically deformed gd x x y in zr ga b solid solutions for magnetocaloric regenerator of parallel Plate Geometry
Journal of Alloys and Compounds, 2018Co-Authors: S V Taskaev, V V Khovaylo, D Karpenkov, I A Radulov, Maxim Ulyanov, D Bataev, A DyakonovAbstract:Abstract Despite significant progress in the study of materials undergoing first-order magnetic phase transitions accompanied by the so-called giant magnetocaloric effect (MCE), Gd metal still remains the most widely used material in prototypes of magnetic refrigerators due to its significant MCE, good machinability and reasonable mechanical and chemical stabilities. Alloying of Gd enables fine-tuning the Curie temperature of Gd-based solid solutions (all show second-order phase transitions), for graded magnetocaloric materials. Commonly, Gd packed spheres are used as a magnetocaloric working substance in the active magnetic regenerator (AMR) cycle. In this work, we show that the optimized stacking parallel-Plate Geometry of AMR bed made of Gd is more effective for application at frequencies 1–10 Hz then the packed spheres. We also give a short review on magnetocaloric properties of cold-rolled Gd-X (X = Y, In, Zr, Ga, B) solid solutions. These materials can be produced in the form of thin (∼100 μm) foils/Plates to ensure rapid heat exchange between to the heat transfer fluid. Although the magnetocaloric effect decreases in the as-rolled foils, it can be recovered by thermal treatment of the final stacked-Plates regenerators. Gd-Y, Gd-In and Gd-Zr solid solutions have magnetocaloric properties, comparable to the MCE of pure Gd in a wide temperature working span up to 37 K, 36 K, and 16 K respectively, which makes them suitable magnetocaloric material systems for testing the fundamental heat exchangers geometries at ambient temperature and in frequencies of 1–10 Hz.
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Plastically deformed Gd-X (X = Y, In, Zr, Ga, B) solid solutions for magnetocaloric regenerator of parallel Plate Geometry
Journal of Alloys and Compounds, 2018Co-Authors: S V Taskaev, V V Khovaylo, D Karpenkov, I A Radulov, Maxim Ulyanov, D Bataev, A Dyakonov, D. Gunderov, Konstantin P. Skokov, Oliver GutfleischAbstract:Abstract Despite significant progress in the study of materials undergoing first-order magnetic phase transitions accompanied by the so-called giant magnetocaloric effect (MCE), Gd metal still remains the most widely used material in prototypes of magnetic refrigerators due to its significant MCE, good machinability and reasonable mechanical and chemical stabilities. Alloying of Gd enables fine-tuning the Curie temperature of Gd-based solid solutions (all show second-order phase transitions), for graded magnetocaloric materials. Commonly, Gd packed spheres are used as a magnetocaloric working substance in the active magnetic regenerator (AMR) cycle. In this work, we show that the optimized stacking parallel-Plate Geometry of AMR bed made of Gd is more effective for application at frequencies 1–10 Hz then the packed spheres. We also give a short review on magnetocaloric properties of cold-rolled Gd-X (X = Y, In, Zr, Ga, B) solid solutions. These materials can be produced in the form of thin (∼100 μm) foils/Plates to ensure rapid heat exchange between to the heat transfer fluid. Although the magnetocaloric effect decreases in the as-rolled foils, it can be recovered by thermal treatment of the final stacked-Plates regenerators. Gd-Y, Gd-In and Gd-Zr solid solutions have magnetocaloric properties, comparable to the MCE of pure Gd in a wide temperature working span up to 37 K, 36 K, and 16 K respectively, which makes them suitable magnetocaloric material systems for testing the fundamental heat exchangers geometries at ambient temperature and in frequencies of 1–10 Hz.
J C Schouten - One of the best experts on this subject based on the ideXlab platform.
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microchannel Plate Geometry optimization for even flow distribution at high flow rates
Chemical Engineering Research & Design, 2004Co-Authors: E R Delsman, A Pierik, M H J M De Croon, Gert Jan Kramer, J C SchoutenAbstract:Microreactors generally consist of microstructured Plates containing a large number of equal channels. The small diameter of the channels enables high heat and mass transfer rates. To exploit this feature and realize a high throughput within a small volume, it is necessary to use high flow rates. However, at these high flow rates it is not straightforward to obtain an even distribution of fluid flow over the individual microchannels. A three-dimensional computational fluid dynamics (CFD) model was used to calculate the flow distribution on a microstructured Plate. Calculation time was reduced by introducing an artificial viscosity in the channel region. The calculations show that a transitional velocity exists, below which the flow distribution is independent of velocity and above which inertia effects start to influence the distribution. To optimize the flow distribution, nine different Plate geometries were studied at flow rates between 0.1 and 100 m s–1, or 4 × 10–4 to 0.4 m3 h–1 per Plate. By optimizing the Plate Geometry, the relative standard deviation of the flow distribution was reduced from 19 to 3%. Furthermore, it is shown that the optimal Geometry depends on the flow rate, which thus needs to be taken into account in the design of microchannel Plates.
A Dyakonov - One of the best experts on this subject based on the ideXlab platform.
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plastically deformed gd x x y in zr ga b solid solutions for magnetocaloric regenerator of parallel Plate Geometry
Journal of Alloys and Compounds, 2018Co-Authors: S V Taskaev, V V Khovaylo, D Karpenkov, I A Radulov, Maxim Ulyanov, D Bataev, A DyakonovAbstract:Abstract Despite significant progress in the study of materials undergoing first-order magnetic phase transitions accompanied by the so-called giant magnetocaloric effect (MCE), Gd metal still remains the most widely used material in prototypes of magnetic refrigerators due to its significant MCE, good machinability and reasonable mechanical and chemical stabilities. Alloying of Gd enables fine-tuning the Curie temperature of Gd-based solid solutions (all show second-order phase transitions), for graded magnetocaloric materials. Commonly, Gd packed spheres are used as a magnetocaloric working substance in the active magnetic regenerator (AMR) cycle. In this work, we show that the optimized stacking parallel-Plate Geometry of AMR bed made of Gd is more effective for application at frequencies 1–10 Hz then the packed spheres. We also give a short review on magnetocaloric properties of cold-rolled Gd-X (X = Y, In, Zr, Ga, B) solid solutions. These materials can be produced in the form of thin (∼100 μm) foils/Plates to ensure rapid heat exchange between to the heat transfer fluid. Although the magnetocaloric effect decreases in the as-rolled foils, it can be recovered by thermal treatment of the final stacked-Plates regenerators. Gd-Y, Gd-In and Gd-Zr solid solutions have magnetocaloric properties, comparable to the MCE of pure Gd in a wide temperature working span up to 37 K, 36 K, and 16 K respectively, which makes them suitable magnetocaloric material systems for testing the fundamental heat exchangers geometries at ambient temperature and in frequencies of 1–10 Hz.
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Plastically deformed Gd-X (X = Y, In, Zr, Ga, B) solid solutions for magnetocaloric regenerator of parallel Plate Geometry
Journal of Alloys and Compounds, 2018Co-Authors: S V Taskaev, V V Khovaylo, D Karpenkov, I A Radulov, Maxim Ulyanov, D Bataev, A Dyakonov, D. Gunderov, Konstantin P. Skokov, Oliver GutfleischAbstract:Abstract Despite significant progress in the study of materials undergoing first-order magnetic phase transitions accompanied by the so-called giant magnetocaloric effect (MCE), Gd metal still remains the most widely used material in prototypes of magnetic refrigerators due to its significant MCE, good machinability and reasonable mechanical and chemical stabilities. Alloying of Gd enables fine-tuning the Curie temperature of Gd-based solid solutions (all show second-order phase transitions), for graded magnetocaloric materials. Commonly, Gd packed spheres are used as a magnetocaloric working substance in the active magnetic regenerator (AMR) cycle. In this work, we show that the optimized stacking parallel-Plate Geometry of AMR bed made of Gd is more effective for application at frequencies 1–10 Hz then the packed spheres. We also give a short review on magnetocaloric properties of cold-rolled Gd-X (X = Y, In, Zr, Ga, B) solid solutions. These materials can be produced in the form of thin (∼100 μm) foils/Plates to ensure rapid heat exchange between to the heat transfer fluid. Although the magnetocaloric effect decreases in the as-rolled foils, it can be recovered by thermal treatment of the final stacked-Plates regenerators. Gd-Y, Gd-In and Gd-Zr solid solutions have magnetocaloric properties, comparable to the MCE of pure Gd in a wide temperature working span up to 37 K, 36 K, and 16 K respectively, which makes them suitable magnetocaloric material systems for testing the fundamental heat exchangers geometries at ambient temperature and in frequencies of 1–10 Hz.
N Phanthien - One of the best experts on this subject based on the ideXlab platform.
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size effect of the parallel Plate Geometry on the rheological behavior of bentonite suspensions
Journal of Rheology, 2020Co-Authors: Wei Wang, Jiawang Chen, N PhanthienAbstract:The change of the rheological behavior of a bentonite suspension with the gap of the parallel-Plate Geometry in a rotational rheometer is investigated. An obvious gap-dependent behavior is found in both the gel and flowing states, based on which it is found that slip at the boundary plays an important role in the viscometric measurement at low shear rates, as well as in the small amplitude oscillatory shear experiment; shear banding is considered to take place at the vicinity of the yielding point, as well as in flows at low shear rates if the boundary slip is suppressed by using rough Plates. Furthermore, relaxation behavior, similar to that of a polymeric system, is observed. The motion of the gel structure is slower with increasing gap, indicating a larger size of the networking structure. This is also the origin for the decrease of the yield stress observed with increasing gap.The change of the rheological behavior of a bentonite suspension with the gap of the parallel-Plate Geometry in a rotational rheometer is investigated. An obvious gap-dependent behavior is found in both the gel and flowing states, based on which it is found that slip at the boundary plays an important role in the viscometric measurement at low shear rates, as well as in the small amplitude oscillatory shear experiment; shear banding is considered to take place at the vicinity of the yielding point, as well as in flows at low shear rates if the boundary slip is suppressed by using rough Plates. Furthermore, relaxation behavior, similar to that of a polymeric system, is observed. The motion of the gel structure is slower with increasing gap, indicating a larger size of the networking structure. This is also the origin for the decrease of the yield stress observed with increasing gap.