共查询到20条相似文献,搜索用时 46 毫秒
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某电厂1#机组为东方汽轮机有限公司生产的N660-25/600/600型超超临界、一次中间再热、冲动式、单轴三缸四排汽、凝汽式汽轮机。本文重点介绍了对该机组的配汽特性曲线以及定滑压曲线进行的优化设计,从而达到提高机组在部分负荷运行经济性的目的。采用优化后的配汽特性曲线和滑压曲线,在350~590MW,机组的热耗值得到了明显的改善,运行经济性得到提高。 相似文献
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定负荷下火电机组最优运行初压的确定 总被引:1,自引:1,他引:0
针对传统的压力优化方法在迭代寻优过程中存在的一些问题,结合汽轮机变工况理论,提出汽轮机定负荷下主蒸汽压力的优化计算方法,利用粒子群算法(PSO)对最优压力进行求取,得出不同负荷下主蒸汽压力的最优运行值,并以某1 000 MW汽轮机为例进行了分析.结果表明:该方法很好地解决了定负荷下压力寻优问题,且可以得出机组的最佳滑压运行方式和最优运行初压,即80%负荷以上时,保持25 MPa定压运行;80%负荷以下时,机组保持2阀全开滑压运行模式,在低负荷区2阀全开滑压运行模式的热经济性明显高于3阀全开滑压运行模式. 相似文献
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Harish C. Barshilia N. Selvakumar K.S. Rajam 《Solar Energy Materials & Solar Cells》2009,93(3):315-323
Spectrally selective AlxOy/Al/AlxOy multilayer absorber coatings were deposited on copper (Cu) and molybdenum (Mo) substrates using a pulsed sputtering system. The Al targets were sputtered using asymmetric bipolar-pulsed DC generators in Ar+O2 and Ar plasmas to deposit an AlxOy/Al/AlxOy coating. The compositions and thicknesses of the individual component layers were optimized to achieve high solar absorptance (α=0.950-0.970) and low thermal emittance (ε=0.05-0.08). The X-ray diffraction data in thin film mode showed an amorphous structure of the AlxOy/Al/AlxOy coating. The X-ray photoelectron spectroscopy data of the AlxOy/Al/AlxOy multilayer absorber indicated that the AlxOy layers present in the coating were non-stoichiometric. The optical constants (n and k) of the multilayer absorber were determined from the spectroscopic ellipsometric data. Drude's free-electron model was used for generating the theoretical dispersion of optical constants for Al films, while the Tauc-Lorentz model was used for modeling optical properties of the dielectric AlxOy layers. In order to study the thermal stability of the AlxOy/Al/AlxOy coatings, they were subjected to heat treatment (in air and vacuum) at different temperatures and durations. The multilayer absorber deposited on Cu substrates exhibited high solar selectivity (α/ε) of 0.901/0.06 even after heat-treatment in air up to 400 °C for 2 h. At 450 °C, the solar selectivity decreased significantly on Cu substrates (e.g., α/ε=0.790/0.07). The coatings deposited on Mo substrates were thermally stable up to 800 °C in vacuum with a solar selectivity of 0.934/0.05. The structural stability of the absorber coatings heat treated in air (up to 400 °C) and vacuum (up to 800 °C) was confirmed by micro-Raman spectroscopy measurements. Studies on the accelerated aging tests suggested that the absorber coatings on Cu were stable in air up to 75 h at 300 °C and the service lifetime of the multilayer absorber was predicted to be more than 25 years. Further, the activation energy for the degradation of the multilayer absorber heat treated for longer durations in air is of the order of 64 kJ/mol. 相似文献
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Yih-Farn Kao Swe-Kai Chen Jen-Haur Sheu Jiun-Ting Lin Wei-En Lin Jien-Wei Yeh Su-Jien Lin Tzung-Hsien Liou Chia-Wen Wang 《International Journal of Hydrogen Energy》2010
This study presents an innovative multi-principal-element CoFeMnTiVZr alloy system for the absorption and desorption of hydrogen. Pressure-composition-isotherms (PCIs) demonstrate that CoFeMnTixVZr, CoFeMnTiVyZr, and CoFeMnTiVZrz can absorb and desorb hydrogen for x, y, and z that satisfy 0.5 ≤ x ≤ 2.5, 0.4 ≤ y ≤ 3.0, and 0.4 ≤ z ≤ 3.0, respectively. X-ray diffraction (XRD) reveals that CoFeMnTixVyZrz alloys have a simple C14 Laves phase with a single set of lattice parameters before and after PCI tests. The distributions of each element in CoFeMnTixVyZrz alloys are roughly equal, as revealed by SEM/EDS mapping. The effects of values x, y, and z on the hydrogen storage properties are elucidated in terms of lattice constant, element segregation, hydride formation enthalpies of the alloy components and hydrogen, and the averaged formation enthalpy. The high-entropy effect promotes the formation of a single C14 Laves phase, and the maximum hydrogen storage capacity is strongly related to the hydride formation enthalpy of the alloy and hydrogen. 相似文献
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A. Di Benedetto V. Di Sarli E. Salzano F. Cammarota G. Russo 《International Journal of Hydrogen Energy》2009
In this work, the explosion behavior of stoichiometric CH4/O2/N2/CO2 and H2/O2/N2/CO2 mixtures has been studied both experimentally and theoretically at different CO2 contents and oxygen air enrichment factors. Peak pressure, maximum rate of pressure rise and laminar burning velocity were measured from pressure time records of explosions occurring in a closed cylindrical vessel. The laminar burning velocity was also computed through CHEMKIN–PREMIX simulations. 相似文献
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基于Senkin模型,应用自编化学反应机理简化程序,结合Kinalc和Mechmod开源程序,发展了详细化学反应机理的简化与验证方法.以电站锅炉燃烧的计算流体力学(CFD)数值模拟为应用背景,建立了考虑C/H/O/N/S/Cl/K/Na元素的详细化学反应机理(115组分,1,342基元反应),并运用此方法得到简化反应机理(28组分,20反应).验证结果表明,该简化机理在锅炉运行的主要参数变化范围内(温度T=1,100~1,500,℃,过量空气系数λ=0.8~1.2)具有较好的准确性和较高的计算效率,可应用于锅炉燃烧的CFD计算. 相似文献
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In this work structural and transport properties of layered LiNi1−y−zCoyMnzO2 (y = 0.25, 0.35, 0.5 and z = 0.1) cathode materials are presented. In the considered group of oxides, LiNi1−y−zCoyMnzO2, there is no clear correlation between electrical conductivity and the a parameter (M-M distance in the octahedra layers). A non-monotonic modification of electrical properties of LixNi0.65Co0.25Mn0.1O2 cathode materials is observed upon lithium deintercalation. 相似文献
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Isaiah O. Oladeji Lee Chow Christos S. Ferekides Vijay Viswanathan Zhiyong Zhao 《Solar Energy Materials & Solar Cells》2000,61(2)
The potential of CdTe/CdS/Cd1−xZnxS structure as an alternative to CdTe/CdS structure in photovoltaic application has been demonstrated. The unoptimized solar cell structure grown on transparent conducting oxide coated soda lime glass of 3 mm thickness with no antireflection coating yielded a 10% efficiency. This efficiency is the highest ever recorded in any Cd1−xZnxS film containing CdTe solar cells. 相似文献
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Layer-structured LiNi1/3Co1/3Mn1/3−yAlyO2 has been synthesized via a sol–gel method. The lattice constants of LiNi1/3Co1/3Mn1/3−yAlyO2 decrease with the concentration of aluminum ions. XANES analysis further confirms that the valence of cobalt ion is 3+, and that of Ni is between 2+ and 3+ in LiNi1/3Co1/3Mn1/3−yAlyO2. With doping aluminum ions, the redox centers for the electrochemical reaction change from nickel ions alone to both nickel and cobalt ions. The amounts of de-intercalatable lithium ions are affected by the concentration of aluminum ions; however, the extracting efficiency of lithium ions is improved by doping aluminum ions. Among all the samples, LiNi1/3Co1/3Mn0.23Al0.1O2 exhibits the best capacity retention and the least irreversible capacity. 相似文献
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R. Bayon R. Musembi A. Belaidi M. Br T. Guminskaya M.-Ch. Lux-Steiner Th. Dittrich 《Solar Energy Materials & Solar Cells》2005,89(1):13-25
A system of highly structured TiO2/In(OH)xSy/PbS/PEDOT:PSS has been developed and investigated by photovoltage spectroscopy, X-ray photo- and Auger electron spectroscopies, electron microscopy, and photovoltaic response. TiO2, In(OH)xSy, PbS, and PEDOT:PSS serve as electron conductor, buffer layer, absorber, and hole conductor, respectively. Both buffer and absorber layers were prepared by chemical bath deposition. The band gap of as-prepared In(OH)xSy varied between 2.4 and 3.5 eV depending on the pH-value of the solution. In addition, the band gap of the PbS could be widened to about 0.85 eV making the application as absorber for solar cells feasible. At present, corresponding solar cell devices reach short-circuit current densities of about 8 mA/cm2 and open-circuit voltages of about 0.3 V. 相似文献
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The addition of dimethoxymethane (DMM or methylal) and diethoxymethane (DEM or ethylal) to a rich ethylene/oxygen/argon flame has been investigated by measuring the depletion of soot precursors. Three rich premixed ethylene/oxygen/argon (with and without added methylal or ethylal) flat flames have been stabilized at low-pressure (50 mbar) on a Spalding–Botha type burner with the same equivalence ratio of 2.50. Identification and monitoring of signal intensity profiles of species within the flames have been carried out by using molecular beam mass spectrometry (M.B.M.S.). The replacement of some C2H4 by C3H8O2 or C5H12O2 is responsible for a decrease of the maximum mole fractions of the detected intermediate species. This phenomenon is noticeable for C2–C4 intermediates and becomes more effective for C5–C10 species, mainly when C3H8O2 added.A new kinetic model has been elaborated and contains 546 reactions and 107 chemical species in order to simulate the three investigated flames: C2H4/O2/Ar, C2H4/DMM/O2/Ar and C2H4/DEM/O2/Ar. The reaction mechanism well reproduces experimental mole fraction profiles of major and intermediate species, and underlines the effect of methylal and ethylal addition on species concentration profiles for these flames. 相似文献
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Akira Matsugi Hiroumi Shiina Akifumi Takahashi Kentaro Tsuchiya Akira Miyoshi 《Combustion and Flame》2014
The combustion characteristics and reaction mechanism of mixtures containing nitrogen trifluoride (NF3) were investigated. Burning velocities for H2/NF3/N2, CH4/NF3/N2, and C3H8/NF3/N2 flames were determined for the first time at various equivalence ratios and N2 mole fractions. The burning velocities of the latter two flames were similar and showed peaks at equivalence ratios of ∼1.0, while those of the H2/NF3/N2 flames had the pronounced peak at low equivalence ratios where the formation of the wrinkled flames was observed. A detailed kinetic model was constructed to simulate the laminar burning velocities of H2/NF3/N2 and CH4/NF3/N2 flames. The model accurately reproduced the experimental results. Analyses of the reaction mechanism revealed the major reaction pathways that involve the decomposition of NF3, the oxidation and chain-fluoridation of H2 and CH4, and the formation of N2. 相似文献