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Multi-objective dynamic optimization model for
China’s road transport energy technology switching
Dan GAO , Zheng LI , Feng FU , Linwei MA
Front. Energy. 2009, 3 (3): 247-253.
https://doi.org/10.1007/s11708-009-0048-3
Deducting the future switching of the road transport energy technology is one of the key preconditions for relative technology development planning. However, one of the difficulties is to address the issue of multi-objective and conflicting constrains, e.g., minimizing the climate mitigation or minimizing economic cost. In this paper, a dynamic optimization model was established, which can be used to analyze the road transport energy technology switching under multi-objective constrains. Through one case study, a series of solutions could be derived to provide decision-makers with the flexibility to choose the appropriate solution with respect to the given situation.
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Synchronous observation of rising soluble bubble
through quiescent solution
Yifu ZHANG , Shuai TIAN , Weizhong LI , Yongchen SONG ,
Front. Energy. 2009, 3 (3): 307-312.
https://doi.org/10.1007/s11708-009-0028-7
An experimental method using computer image processing technology (CIPT) was proposed to observe and investigate the velocity, deformation, heat and mass transfer, etc. of a rising soluble gas (CO2) bubble through a quiescent hot water. A model was set up to describe the behavior of the bubble in a visual experimental system in which a high-speed camera rose instantaneously with the movement of the bubble. A series of trajectory videos about the bubble were recorded by a computer linked to the camera. The trajectory, volume changes and rate of mass transfer of the bubble were obtained by the CIPT. It is found that the single bubble follows a rolling trajectory at the initial stage when there is mass transfer. With the volume decreasing, the disturbed behavior of the bubble becomes tempered. When the rising velocity of the bubble reaches the maximum, the velocity is nearly at a constant. The experimental and analysis results show that this method is useful for the research on the mass transfer and the movement of rising bubbles in liquid.
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Cooling performance of grid-sheets for highly
loaded ultra-supercritical steam turbines
Dieter BOHN , Robert KREWINKEL , Shuqing TIAN ,
Front. Energy. 2009, 3 (3): 313-320.
https://doi.org/10.1007/s11708-009-0036-7
In order to increase efficiency and achieve a further CO2-reduction, the next generation of power plant turbines will have steam turbine inlet temperatures that are considerably higher than the current ones. The high pressure steam turbine inlet temperature is expected to be increased up to approximately 700°C with a live steam pressure of 30MPa. The elevated steam parameters in the high and intermediate pressure turbines can be encountered with Ni-base alloys, but this is a costly alternative associated with many manufacturing difficulties. Collaborative research centre 561 “Thermally Highly Loaded, Porous and Cooled Multi-Layer Systems for Combined Cycle Power Plants” at RWTH Aachen University proposes cooling the highly loaded turbines instead, as this would necessitate the application of far less Ni-base alloys. To protect the thermally highly loaded components, a sandwich material consisting of two thin face sheets and a core made from a woven wire mesh is used to cover the walls of the steam turbine casing. The cooling steam is led through the woven wire mesh between the two face sheets to achieve a cooling effect. The wire mesh provides the grid-sheet with structural rigidity under varying operating conditions. In the present work, the cooling performance of the grid-sheets will be investigated applying the conjugate heat transfer method to ultra-supercritical live and cooling steam conditions for a section of the cooling structure. The behaviour of the flow and the heat transfer in the grid-sheet will be analyzed in detail using a parameter variation. The numerical results should give a first prediction of the cooling performance under future operating conditions.
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Exhaust hood for steam turbines-single-flow arrangement
Michal HOZNEDL , Ladislav TAJC , Jaroslav KREJCIK , Lukas BEDNAR , Kamil SEDLAK , Jiri LINHART ,
Front. Energy. 2009, 3 (3): 321-329.
https://doi.org/10.1007/s11708-009-0039-4
In the past, increased attention was given to the development of an optimal shape for the inlet part of LP turbine casings in SKODA POWER. A double-flow design is typically used for high power output turbines. An optimized shape for the internal diffuser has been found, which transforms the kinetic energy of steam into increased pressure, thus effectively increasing the thermodynamic efficiency of the stage. Some conclusions have been drawn from laboratory experiments, others derived directly from on-site measurements at power plants. The conclusions from the development of double-flow turbines form the basis for the design of the single-flow turbine arrangement. Single-flow design is typically used for lower output turbines. There are still some limitations in applying this arrangement. The designer needs to resolve the bearing position and how to ensure access to them. Reinforcing the ribs and supports are used, therefore, to ensure the rigidity of the entire casing. The optimization of the single-flow diffuser shape is therefore the subject of the study presented below.
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Status of domestic gasification technology in
China
Zhimin HUANG , Jiansheng ZHANG , Guangxi YUE ,
Front. Energy. 2009, 3 (3): 330-336.
https://doi.org/10.1007/s11708-009-0021-1
Five domestic gasification technologies in China were presented and reviewed, including opposed multi-burner (OMB) gasification technology of coal water slurry (CWS), oxygen staged gasification technology, two-stage dry feed entrained flow gasification, pulverized coal gasification process of HT-L, and ash agglomerating fluidized bed gasification. The former four technologies belong to pressurized entrained flow gasification technology. The process description, technology characteristics, research and development process, performance indexes and commercialization progress of these technologies were mainly discussed.
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Development of MCBurn and its application in
the analysis of SCWR physical characteristics
Ganglin YU , Kan WANG ,
Front. Energy. 2009, 3 (3): 348-352.
https://doi.org/10.1007/s11708-009-0031-z
The MCBurn, a coupled code system linking the Monte Carlo N-particle transport code(MCNP) and Oak Ridge isotope generation and depletion code (ORIGEN), can resolve the basic calculation problems in reactor physical design and analysis, such as criticality, power distribution, nuclide burn up, and neutron fluence. It has been verified in the pressurized water reactor (PWR) pin model, fast reactor (FR) burn up model, and boiling water reactor(BWR) assemble model with benchmarked results. In supercritical water reactor (SCWR) physical calculations, the calculation conditions such as the geometry, the neutron spectrum, and the fuel materials, etc., are more complex than those in traditional reactors, which is a great challenge to reactor physics calculation code. However, the MCBurn code is a possible solution. In this paper, several update functions of the MCBurn in new neutron cross-section lib, code interface, and neutron flux distribution were described. The application of the MCBurn in SCWR were verified on a supercritical water reactor assemble. The calculation results show that the MCBurn is accurate and adaptable in the SCWR calculation.
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Syngas composition study
Zhe WANG , Jinning YANG , Zheng LI , Yong XIANG ,
Front. Energy. 2009, 3 (3): 369-372.
https://doi.org/10.1007/s11708-009-0044-7
The syngas composition characteristic was investigated in the real slurry-feed gasifier using a detailed gas phase reaction mechanism. The results show that the time for syngas to reach equilibrium is much shorter than the residence time for slurry feed entrained-flow gasifiers, indicating a gas phase species partial equilibrium state. Further calculation shows that the four major species, CO, CO 2, H 2, and H 2O, are in equilibrium via the reaction . Suggestions are provided for future modeling and model validation.
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15 articles
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