The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform
Ali Turan - One of the best experts on this subject based on the ideXlab platform.
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Mechanical Equilibrium operation integrated modelling of recuperative solid oxide fuel cell gas turbine hybrid systems design conditions and off design analysis
Applied Energy, 2021Co-Authors: Yu Huang, Ali TuranAbstract:Abstract A novel model integrating Mechanical Equilibrium operation, electrochemical reactions and other thermodynamic processes has been built in this research to gain energetic and operational insights into recuperative solid oxide fuel cell – gas turbine hybrid systems. Determination mechanism for Equilibrium running is proposed for both design stage analysis and off-design operation through reanalysis of classical speed and flow compatibility requirements. The coupling with solid oxide fuel cells and inclusion of a recuperator substantively introduces several independent variables to the related equation, while the number of independent parameters decreases in modelling when matching issues of turbomachinery are taken into account. Compared to simple hybridization, there are increasingly complex mutual influence and constraints between upstream and downstream parameters that are linked by the heat recovery process. Quantitative analysis of factors in turbine design shows 14–16% higher system efficiency with component pressure losses taken into consideration. When the turbine is appropriately designed, an electric efficiency of 68% can be achieved with recuperator effectiveness of 0.9. Results also highlight the significantly expanded operating ranges of turbomachinery under lower recuperator effectiveness of 0.8 as compensation for a 3% lower electrical efficiency at design conditions. A performance map for the proposed system is developed based on off-design operation analysis with stable running state ensured throughout.
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Mechanical Equilibrium operation integrated modelling of recuperative solid oxide fuel cell – gas turbine hybrid systems: Design conditions and off-design analysis
Applied Energy, 2021Co-Authors: Yu Huang, Ali TuranAbstract:Abstract A novel model integrating Mechanical Equilibrium operation, electrochemical reactions and other thermodynamic processes has been built in this research to gain energetic and operational insights into recuperative solid oxide fuel cell – gas turbine hybrid systems. Determination mechanism for Equilibrium running is proposed for both design stage analysis and off-design operation through reanalysis of classical speed and flow compatibility requirements. The coupling with solid oxide fuel cells and inclusion of a recuperator substantively introduces several independent variables to the related equation, while the number of independent parameters decreases in modelling when matching issues of turbomachinery are taken into account. Compared to simple hybridization, there are increasingly complex mutual influence and constraints between upstream and downstream parameters that are linked by the heat recovery process. Quantitative analysis of factors in turbine design shows 14–16% higher system efficiency with component pressure losses taken into consideration. When the turbine is appropriately designed, an electric efficiency of 68% can be achieved with recuperator effectiveness of 0.9. Results also highlight the significantly expanded operating ranges of turbomachinery under lower recuperator effectiveness of 0.8 as compensation for a 3% lower electrical efficiency at design conditions. A performance map for the proposed system is developed based on off-design operation analysis with stable running state ensured throughout.
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Mechanical Equilibrium operation integrated modelling of hybrid sofc gt systems design analyses and off design optimization
Energy, 2020Co-Authors: Yu Huang, Ali TuranAbstract:Abstract A novel model has been built in this research integrating Mechanical Equilibrium operation, electrochemical reactions and other thermodynamic processes to gain insights into SOFC – GT hybrid systems in both energetic and operational aspects. To deliver the recommended SOFC pressure of 4–7 bar, a centrifugal compressor of high compression ratio is employed, and the matching issues of turbomachinery are newly analyzed to account for the disruption of SOFCs to the operation of single-shaft gas turbines. The number of independent parameters decreases in hybrid system modelling when speed and flow compatibilities are contained to ensure turbomachinery running stably without acceleration or deceleration. Compared to conventional gas turbines, however, the coupling of SOFCs substantively introduces at least two independent variables to the flow compatibility equation, in which two of the unknown terms are essentially assigned by different air and fuel utilization. When the turbine is appropriately designed with pressure loss considerations, an electric efficiency of 48.0% can be achieved by the simple system without surge risk of the compressor. Results also highlight the improvement effects of the coupling technology under off-design conditions. In ideal case, an electric efficiency of 44.4% can still be achieved at 46% designed power output.
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Mechanical Equilibrium operation integrated modelling of hybrid SOFC – GT systems: Design analyses and off-design optimization
Energy, 2020Co-Authors: Yu Huang, Ali TuranAbstract:Abstract A novel model has been built in this research integrating Mechanical Equilibrium operation, electrochemical reactions and other thermodynamic processes to gain insights into SOFC – GT hybrid systems in both energetic and operational aspects. To deliver the recommended SOFC pressure of 4–7 bar, a centrifugal compressor of high compression ratio is employed, and the matching issues of turbomachinery are newly analyzed to account for the disruption of SOFCs to the operation of single-shaft gas turbines. The number of independent parameters decreases in hybrid system modelling when speed and flow compatibilities are contained to ensure turbomachinery running stably without acceleration or deceleration. Compared to conventional gas turbines, however, the coupling of SOFCs substantively introduces at least two independent variables to the flow compatibility equation, in which two of the unknown terms are essentially assigned by different air and fuel utilization. When the turbine is appropriately designed with pressure loss considerations, an electric efficiency of 48.0% can be achieved by the simple system without surge risk of the compressor. Results also highlight the improvement effects of the coupling technology under off-design conditions. In ideal case, an electric efficiency of 44.4% can still be achieved at 46% designed power output.
Yu Huang - One of the best experts on this subject based on the ideXlab platform.
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Mechanical Equilibrium operation integrated modelling of recuperative solid oxide fuel cell gas turbine hybrid systems design conditions and off design analysis
Applied Energy, 2021Co-Authors: Yu Huang, Ali TuranAbstract:Abstract A novel model integrating Mechanical Equilibrium operation, electrochemical reactions and other thermodynamic processes has been built in this research to gain energetic and operational insights into recuperative solid oxide fuel cell – gas turbine hybrid systems. Determination mechanism for Equilibrium running is proposed for both design stage analysis and off-design operation through reanalysis of classical speed and flow compatibility requirements. The coupling with solid oxide fuel cells and inclusion of a recuperator substantively introduces several independent variables to the related equation, while the number of independent parameters decreases in modelling when matching issues of turbomachinery are taken into account. Compared to simple hybridization, there are increasingly complex mutual influence and constraints between upstream and downstream parameters that are linked by the heat recovery process. Quantitative analysis of factors in turbine design shows 14–16% higher system efficiency with component pressure losses taken into consideration. When the turbine is appropriately designed, an electric efficiency of 68% can be achieved with recuperator effectiveness of 0.9. Results also highlight the significantly expanded operating ranges of turbomachinery under lower recuperator effectiveness of 0.8 as compensation for a 3% lower electrical efficiency at design conditions. A performance map for the proposed system is developed based on off-design operation analysis with stable running state ensured throughout.
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Mechanical Equilibrium operation integrated modelling of recuperative solid oxide fuel cell – gas turbine hybrid systems: Design conditions and off-design analysis
Applied Energy, 2021Co-Authors: Yu Huang, Ali TuranAbstract:Abstract A novel model integrating Mechanical Equilibrium operation, electrochemical reactions and other thermodynamic processes has been built in this research to gain energetic and operational insights into recuperative solid oxide fuel cell – gas turbine hybrid systems. Determination mechanism for Equilibrium running is proposed for both design stage analysis and off-design operation through reanalysis of classical speed and flow compatibility requirements. The coupling with solid oxide fuel cells and inclusion of a recuperator substantively introduces several independent variables to the related equation, while the number of independent parameters decreases in modelling when matching issues of turbomachinery are taken into account. Compared to simple hybridization, there are increasingly complex mutual influence and constraints between upstream and downstream parameters that are linked by the heat recovery process. Quantitative analysis of factors in turbine design shows 14–16% higher system efficiency with component pressure losses taken into consideration. When the turbine is appropriately designed, an electric efficiency of 68% can be achieved with recuperator effectiveness of 0.9. Results also highlight the significantly expanded operating ranges of turbomachinery under lower recuperator effectiveness of 0.8 as compensation for a 3% lower electrical efficiency at design conditions. A performance map for the proposed system is developed based on off-design operation analysis with stable running state ensured throughout.
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Mechanical Equilibrium operation integrated modelling of hybrid sofc gt systems design analyses and off design optimization
Energy, 2020Co-Authors: Yu Huang, Ali TuranAbstract:Abstract A novel model has been built in this research integrating Mechanical Equilibrium operation, electrochemical reactions and other thermodynamic processes to gain insights into SOFC – GT hybrid systems in both energetic and operational aspects. To deliver the recommended SOFC pressure of 4–7 bar, a centrifugal compressor of high compression ratio is employed, and the matching issues of turbomachinery are newly analyzed to account for the disruption of SOFCs to the operation of single-shaft gas turbines. The number of independent parameters decreases in hybrid system modelling when speed and flow compatibilities are contained to ensure turbomachinery running stably without acceleration or deceleration. Compared to conventional gas turbines, however, the coupling of SOFCs substantively introduces at least two independent variables to the flow compatibility equation, in which two of the unknown terms are essentially assigned by different air and fuel utilization. When the turbine is appropriately designed with pressure loss considerations, an electric efficiency of 48.0% can be achieved by the simple system without surge risk of the compressor. Results also highlight the improvement effects of the coupling technology under off-design conditions. In ideal case, an electric efficiency of 44.4% can still be achieved at 46% designed power output.
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Mechanical Equilibrium operation integrated modelling of hybrid SOFC – GT systems: Design analyses and off-design optimization
Energy, 2020Co-Authors: Yu Huang, Ali TuranAbstract:Abstract A novel model has been built in this research integrating Mechanical Equilibrium operation, electrochemical reactions and other thermodynamic processes to gain insights into SOFC – GT hybrid systems in both energetic and operational aspects. To deliver the recommended SOFC pressure of 4–7 bar, a centrifugal compressor of high compression ratio is employed, and the matching issues of turbomachinery are newly analyzed to account for the disruption of SOFCs to the operation of single-shaft gas turbines. The number of independent parameters decreases in hybrid system modelling when speed and flow compatibilities are contained to ensure turbomachinery running stably without acceleration or deceleration. Compared to conventional gas turbines, however, the coupling of SOFCs substantively introduces at least two independent variables to the flow compatibility equation, in which two of the unknown terms are essentially assigned by different air and fuel utilization. When the turbine is appropriately designed with pressure loss considerations, an electric efficiency of 48.0% can be achieved by the simple system without surge risk of the compressor. Results also highlight the improvement effects of the coupling technology under off-design conditions. In ideal case, an electric efficiency of 44.4% can still be achieved at 46% designed power output.
Robert W. Style - One of the best experts on this subject based on the ideXlab platform.
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The Mechanical Equilibrium of soft solids with surface elasticity
Soft matter, 2018Co-Authors: Robert W. StyleAbstract:Recent experiments have shown that surface stresses in soft materials can have a significant strain-dependence. Here we explore the implications of this surface elasticity to show how, and when, we expect it to arise. We develop the appropriate boundary condition, showing that it simplifies significantly in certain cases. We show that surface elasticity's main role is to effectively stiffen a solid surface's response to in-plane tractions, in particular at length-scales smaller than a characteristic elastocapillary length. We also investigate how surface elasticity effects the Green's-function problem of a line force on a flat, linear-elastic substrate. There are significant changes to this solution, especially in that the well-known displacement singularity is regularised. This raises interesting implications for soft phenomena like wetting contact lines, adhesion and friction. Finally, we discuss open questions, future directions, and close ties with existing fields of research.
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the Mechanical Equilibrium of soft solids with surface elasticity
Soft Matter, 2018Co-Authors: Robert W. StyleAbstract:Recent experiments have shown that surface stresses in soft materials can have a significant strain-dependence. Here we explore the implications of this surface elasticity to show how, and when, we expect it to arise. We develop the appropriate boundary condition, showing that it simplifies significantly in certain cases. We show that surface elasticity's main role is to stiffen a solid surface's response to in-plane tractions, in particular at length-scales smaller than a characteristic elastocapillary length. We also investigate how surface elasticity affects the Green's-function problem of a line force on a flat, incompressible, linear-elastic substrate. There are significant changes to this solution, especially in that the well-known displacement singularity is regularised. This raises interesting implications for soft phenomena like wetting contact lines, adhesion and friction. Finally, we discuss open questions, future directions, and close ties with existing fields of research.
Manuel Lopes - One of the best experts on this subject based on the ideXlab platform.
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A container loading algorithm with static Mechanical Equilibrium stability constraints
Transportation Research Part B: Methodological, 2016Co-Authors: A. Galrão Ramos, José Fernando Oliveira, José Fernando Gonçalves, Manuel LopesAbstract:The Container Loading Problem (CLP) literature has traditionally guaranteed cargo static stability by imposing the full support constraint for the base of the box. Used as a proxy for real-world static stability, this constraint excessively restricts the container space utilization and has conditioned the algorithms developed for this problem. In this paper we propose a container loading algorithm with static stability constraints based on the static Mechanical Equilibrium conditions applied to rigid bodies, which derive from Newton’s laws of motion. The algorithm is a multi-population biased random-key genetic algorithm, with a new placement procedure that uses the maximal-spaces representation to manage empty spaces, and a layer building strategy to fill the maximal-spaces. The new static stability criterion is embedded in the placement procedure and in the evaluation function of the algorithm. The new algorithm is extensively tested on well-known literature benchmark instances using three variants: no stability constraint, the classical full base support constraint and with the new static stability constraint—a comparison is then made with the state-of-the-art algorithms for the CLP. The computational experiments show that by using the new stability criterion it is always possible to achieve a higher percentage of space utilization than with the classical full base support constraint, for all classes of problems, while still guaranteeing static stability. Moreover, for highly heterogeneous cargo the new algorithm with full base support constraint outperforms the other literature approaches, improving the best solutions known for these classes of problems.
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A physical packing sequence algorithm for the container loading problem with static Mechanical Equilibrium conditions
International Transactions in Operational Research, 2014Co-Authors: A. Galrão Ramos, José Fernando Oliveira, Manuel LopesAbstract:The container loading problem (CLP) is a combinatorial optimization problem for the spatial arrangement of cargo inside containers so as to maximize the usage of space. The algorithms for this problem are of limited practical applicability if real-world constraints are not considered, one of the most important of which is deemed to be stability. This paper addresses static stability, as opposed to dynamic stability, looking at the stability of the cargo during container loading. This paper proposes two algorithms. The first is a static stability algorithm based on static Mechanical Equilibrium conditions that can be used as a stability evaluation function embedded in CLP algorithms (e.g. constructive heuristics, metaheuristics). The second proposed algorithm is a physical packing sequence algorithm that, given a container loading arrangement, generates the actual sequence by which each box is placed inside the container, considering static stability and loading operation efficiency constraints
Scott G. Gregory - One of the best experts on this subject based on the ideXlab platform.
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Mechanical Equilibrium of hot large scale magnetic loops on t tauri stars
Monthly Notices of the Royal Astronomical Society, 2012Co-Authors: Alicia Aarnio, Joe Llama, Moira Jardine, Scott G. GregoryAbstract:The most extended, closed magnetic loops inferred on T Tauri stars confine hot, X-ray-emitting plasma at distances from the stellar surface beyond the X-ray-bright corona and closed large-scale field, distances comparable to the corotation radius. Mechanical Equilibrium models have shown that dense condensations, or ‘slingshot prominences’, can rise to great heights due to their density and temperatures cooler than their environs. On T Tauri stars, however, we detect plasma at temperatures hotter than the ambient coronal temperature. By previous model results, these loops should not reach the inferred heights of tens of stellar radii where they likely no longer have the support of the external field against magnetic tension. In this work, we consider the effects of a stellar wind and show that indeed hot loops that are negatively buoyant can attain a Mechanical Equilibrium at heights above the typical extent of the closed corona and the corotation radius.
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Mechanical Equilibrium of Hot, Large-Scale Magnetic Loops on T Tauri Stars
Monthly Notices of the Royal Astronomical Society, 2012Co-Authors: Alicia Aarnio, Joe Llama, Moira Jardine, Scott G. GregoryAbstract:The most extended, closed magnetic loops inferred on T Tauri stars confine hot, X-ray emitting plasma at distances from the stellar surface beyond the the X-ray bright corona and closed large-scale field, distances comparable to the corotation radius. Mechanical Equilibrium models have shown that dense condensations, or "slingshot prominences", can rise to great heights due to their density and temperatures cooler than their environs. On T Tauri stars, however, we detect plasma at temperatures hotter than the ambient coronal temperature. By previous model results, these loops should not reach the inferred heights of tens of stellar radii where they likely no longer have the support of the external field against magnetic tension. In this work, we consider the effects of a stellar wind and show that indeed, hot loops that are negatively buoyant can attain a Mechanical Equilibrium at heights above the typical extent of the closed corona and the corotation radius.
