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Design Optimization and Operating Performance of S-CO_(2) Brayton Cycle under Fluctuating Ambient Temperature and Diverse Power Demand Scenarios

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Journal of Thermal Science 2024年第1期33卷 190-206页

作者： YANG Jingze YANG Zhen duan yuanyuan Key Laboratory for Thermal Science and Power Engineering of MOE Beijing Key Laboratory for CO_(2) Utilization and Reduction TechnologyTsinghua UniversityBeijing 100084China

The supercritical CO_(2)(S-CO_(2)) Brayton cycle is expected to replace steam cycle in the application of solar power tower system due to the attractive potential to improve efficiency and reduce *** the concentrated solar power plant with thermal energy storage is usually located in drought area and used to provide a dispatchable power output,the S-CO_(2) Brayton cycle has to operate under fluctuating ambient temperature and diverse power demand *** addition,the cycle design condition will directly affect the off-design *** this work,the combined effects of design condition,and distributions of ambient temperature and power demand on the cycle operating performance are analyzed,and the off-design performance maps are proposed for the first time.A cycle design method with feedback mechanism of operating performance under varied ambient temperature and power demand is introduced *** show that the low design value of compressor inlet temperature is not conductive to efficient operation under low loads and sufficient output under high ambient *** average yearly efficiency is most affected by the average power demand,while the load cover factor is significantly influenced by the average ambient *** multi-objective optimization,the optimal solution of designed compressor inlet temperature is close to the minimum value of35℃ in Delingha with low ambient temperature,while reaches 44.15℃ in Daggett under the scenario of high ambient temperature,low average power demand,long duration and large value of peak load during the peak temperature *** the cycle designed with compressor inlet temperature of 35℃ instead of 44.15℃ in Daggett under light industry power demand,the reduction of load cover factor will reach 0.027,but the average yearly efficiency can barely be improved.

关键词： supercritical CO_(2)Brayton cycle ambient temperature fluctuating power demand scenarios design optimization off-design performance

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选煤厂筒仓内混凝土填料工程量的求解计算

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煤炭工程 2024年第8期56卷 32-37页

作者：段元元中煤科工集团北京华宇工程有限公司天津分公司天津300121

针对选煤厂筒仓底部结构空间形状复杂,混凝土填料体积计算精度不足的问题,详细探讨了两种不同的计算方法。首先,提出一种基于Excel表格参数化输入及空间分割技术的方案,即将复杂区域划分为n个可量化处理的弓形面积,通过累加这些细分区... 详细信息

针对选煤厂筒仓底部结构空间形状复杂,混凝土填料体积计算精度不足的问题,详细探讨了两种不同的计算方法。首先,提出一种基于Excel表格参数化输入及空间分割技术的方案,即将复杂区域划分为n个可量化处理的弓形面积,通过累加这些细分区域的体积以近似得到整体填料体积,这种方法称为分割法;其次,运用微积分原理对筒仓内壁与方形开口间过渡区域的三维几何体进行解析计算,从而得出更为精确的数学模型。通过对这两种方法的对比分析及与实测结果的比对,结果发现,分割法优势在于直观易懂,适合快速估算,误差为-0.90%;而微积分法则具有较高的理论精度,适用于复杂形态下的精确计算,误差低至0.46%。

关键词：选煤厂筒仓混凝土填料工程量分割法微积分法现场验证

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高原鼢鼠驱动高寒草甸土壤碳氮含量变化的时效性

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中国草地学报 2024年第5期46卷 91-100页

作者：王玲玲李捷段媛媛刘彩凤吴彤郭正刚兰州大学草地农业科技学院甘肃兰州730020

为明确小型地下啮齿动物鼠丘效应和边缘效应影响土壤碳氮含量的时效性,本研究采用分区取样法研究青藏高原东北缘高寒草甸0~20 cm土层有机碳和氮随高原鼢鼠(Eospalax baileyi)鼠丘恢复年限的变化特征。结果表明:鼠丘效应影响土壤有机碳... 详细信息

为明确小型地下啮齿动物鼠丘效应和边缘效应影响土壤碳氮含量的时效性,本研究采用分区取样法研究青藏高原东北缘高寒草甸0~20 cm土层有机碳和氮随高原鼢鼠(Eospalax baileyi)鼠丘恢复年限的变化特征。结果表明:鼠丘效应影响土壤有机碳、全氮、铵态氮、硝态氮含量及C∶N和铵态氮/硝态氮(ANR),具有明显的时效性。其中,鼠丘不同土层的有机碳含量、0~10 cm土层的铵态氮含量和C∶N在第4年时恢复至对照区水平,鼠丘0~10 cm土层的全氮、硝态氮含量和ANR在第3年时恢复至对照区水平;10~20 cm土层,鼠丘土壤硝态氮和铵态氮含量在第5年恢复至对照区水平,土壤全氮在第1年恢复至对照区水平。边缘效应影响土壤有机碳、全氮、铵态氮和硝态氮含量及C∶N,亦表现出明显的时效性。其中,边缘区不同土层的铵态氮含量在第4年时恢复至对照区水平;0~10 cm土层,边缘区的土壤硝态氮、有机碳含量在第3年时恢复至对照区水平,土壤全氮含量和C∶N在第5年恢复至对照区水平;边缘区10~20 cm土层的硝态氮含量在第2年恢复至对照区水平。

关键词：高寒草甸鼠丘效应边缘效应有机碳氮 C∶N ANR

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Power Generation Systems Using Continuous Blowdown Waste Heat from Drum Boilers Driving an Organic Rankine Cycle

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中国电机工程学报 2013年第35期33卷 I0001-I0014页

作者： LIU Qiang duan yuanyuan WAN Xucai Tsinghua University CPECC Southwest Electric Power Design Institute

提出了一种利用汽包锅炉排污系统余热的有机朗肯循环发电系统,有机工质回收扩容器疏水的热量,并通过气轮机发电。建立了系统的热力性能分析模型,并对R227ea、RC318、R236ea、R245fa、R245ca、R123和R113等7种工质的热力性能进行了优化... 详细信息

提出了一种利用汽包锅炉排污系统余热的有机朗肯循环发电系统,有机工质回收扩容器疏水的热量,并通过气轮机发电。建立了系统的热力性能分析模型,并对R227ea、RC318、R236ea、R245fa、R245ca、R123和R113等7种工质的热力性能进行了优化。结果表明,临界温度高的工质,其o2循环的最佳主气温度（蒸发温度）反而低；亚临界循环采用干流体时,过热不利于余热的利用；超临界循环可以改善热源与工质间的温度匹配,有利于增大系统输出功,但是其运行压力高、大比热区的传热恶化等问题是实际运行和设计需要考虑的因素；R236ea的热力性能优于其余6种工质。

关键词：朗肯循环余热驱动连续排污发电系统锅炉燃煤电厂标准煤耗率发电量

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Structure and flow calculation of cake layer on microfiltration membranes

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Journal of Environmental Sciences 2017年第6期29卷 95-101页

作者： Yadong Yu Zhen Yang yuanyuan duan Key Laboratory for Thermal Science and Power Engineering of MOE Beijing Key Laboratory for CO2 Utilization and Reduction TechnologyTsinghua UniversityBeijing 100084China

Submerged membrane bioreactors （SMBR） are widely used in wastewater treatment. The permeability of a membrane declines rapidly because of the formation of a cake layer on the membrane surface. In this paper, a multiple staining protocol was conducted to probe the four major foulants in the cake layer formed on a filtration membrane. Fluorescent images of the foulants were obtained using a confocal laser scanning microscope （CLSM）. The three dimensional structure of the cake layer was reconstructed, and the internal flow was calculated using computational fluid dynamics （CFD）. Simulation results agreed well with the experimental data on the permeability of the cake layer during filtration and showed better accuracy than the calculation by Kozeny-Carman method. B-D-Glucopyranose polysaccharides and proteins are the two main foulants with relatively large volume fractions, while a-D-glucopyranose polysaccharides and nucleic acids have relatively large specific surface areas. The fast growth of B-D-glucopyranose polysaccharides in the volume fraction is mainly responsible for the increase in cake volume fraction and the decrease in permeability. The specific area, or the aggregation/dispersion of foulants, is less important to its permeability compared to its volume fraction.

关键词： Membrane fouling CLSM Cake layer CFD Permeability

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Multiparameter optimization and configuration comparison of supercritical CO_(2) Brayton cycles based on efficiency and cost tradeoff

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Science China(Technological Sciences) 2021年第10期64卷 2084-2098页

作者： LIU TianYe YANG JingZe YANG Zhen duan yuanyuan Key Laboratory for Thermal Science and Power Engineering of MOE Beijing Key Laboratory for CO_(2)Utilization and Reduction TechnologyTsinghua UniversityBeijing 100084China

Supercritical CO_(2)Brayton cycle has high efficiency,compactness,and excellent power generation *** the design of the cycle,some parameters,such as recuperator pinch point temperature difference(ΔTrec,pp),turbine inlet temperature(Ttur,in),and maximum cycle pressure(pmax),are often preset without ***,different preferences on efficiency and cost tradeoff can significantly affect the optimal design of the cycle,and the influence of different parameters on the design condition and the optimum cycle configuration becomes unclear as the preference *** this study,different preferences on efficiency and cost tradeoff are considered,and the effects of cycle configuration and optimization parameter addition on the tradeoff are *** addition,four configurations under different preferences on tradeoff are *** show that the design condition parametersΔT_(rec,pp) decrease and T_(tur,in) and pmax increase as the preference of thermal efficiency(W_(th))*** optimized parameters affect the results of the design point and cycle *** addition,the simple recuperative cycle and reheating cycle are recommended when low cycle initial cost dominates(W_(th)0.701).The decision maker can select appropriate configuration according to specific preferences.

关键词： supercritical CO_(2)Brayton cycle multi-objective optimization decision preference optimized parameter analysis cycle configuration comparison

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Reply to Comment on“Chemical vapor deposition synthesis and Raman scattering investigation of quasi-one-dimensional ZrS3 nanoflakes”

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Nano Research 2024年第9期17卷 8649-8650页

作者： Yang Chen yuanyuan Jin Junqiang Yang Yizhang Ren Zhuojun duan Xiao Liu Jian Sun Song Liu Xukun Zhu Xidong duan Institute of Chemical Biology and Nanomedicine(ICBN) College of Chemistry and Chemical EngineeringHunan UniversityChangsha 410082China Hunan Key Laboratory of Two-Dimensional Materials and State Key Laboratory for Chemo/Biosensing and Chemometrics College of Chemistry and Chemical EngineeringHunan UniversityChangsha 410082China Department of Chemistry Southern University of Science and TechnologyShenzhen 518055China School of Physics and Electronics Central South UniversityChangsha 410083China

1 Introduction Thanks very much for *** taking time to comment on our recent paper regarding“Chemical vapor deposition synthesis and Raman scattering investigation of quasi-one-dimensional ZrS3 nanoflakes”.We summarize the suggestions of *** as made in the comment[1].First,*** suggested that there are just three peaks of two S 2p doublets in Fig.2(b)in the original paper[1],which is inconsistent to the four peaks of previous reports[2-4].Second,*** mentioned that the ratio of two S 2p doublets is helpful to identify the sulfur vacancies,which have a great impact on the n-type semiconducting nature of ***,*** mentioned that Zr 3d peak appearing at 184.7 eV is wider than previous reports[2,4],which may be accounted by the appearance of ZrS2O,and Zr remains in the tetravalent state.

关键词： state. synthesis quasi

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Ultrathin planar broadband absorber through effective medium design

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Nano Research 2016年第8期9卷 2354-2363页

作者： Dong Liu Haitong Yu Zhen Yang yuanyuan duan School of Energy and Power Engineering Nanjing University of Science & Technology Nanjing 210094 China Key Laboratory of Thermal Science and Power Engineering of Ministry of Education Key Laboratory for CO2 Utilization and Reduction Technology Tsinghua University Beijing 100084 China

Ultrathin planar absorbers hold promise in solar energy systems because they can reduce the material, fabrication, and system cost. Here, we present a general strategy of effective medium design to realize ultrathin planar broadband absorbers. The absorber consists of two ultrathin absorbing dielectrics to design an effective absorbing medium, a transparent layer, and metallic substrate. Compared with previous studies, this strategy provides another dimension of freedom to enhance optical absorption; therefore, destructive interference can be realized over a broad spectrum. To demonstrate the power and simplicity of this strategy, we both experimentally and theoretically characterized an absorber with 5-nm-thick Ge, 10-nm-thick Ti, and 50-nm-thick SiO2 films coated on an Ag substrate fabricated using simple deposition methods. Absorptivity higher than 80% was achieved in 15-nm-thick （1/50 of the center wavelength） Ge and Ti films from 400 nm to near 1 btm. As an application example, we experimentally demonstrated that the absorber exhibited a normal solar absorptivity of 0.8 with a normal emittance of 0.1 at 500 ~C, thus demonstrating its potential in solar thermal systems. The effective medium design strategy is general and allows material versatility, suggesting possible applications in real-time optical manipulation using dynamic materials.

关键词： ultrathin planar film broadband absorber effective medium design solar energy

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高能激光光束质量β因子测量方法

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应用光学 2024年第3期45卷 537-542页

作者：阴万宏董再天张云龙王文涛刘磊陈豪远段园园吴磊黎高平于东钰吴沛俞兵孙鹏程西安应用光学研究所、国防科技工业光学一级计量站陕西西安710065 中国电子科技集团公司第十一研究所、固体激光技术重点实验室北京100020

高能激光光束质量β因子测量装置主要用于强激光系统状态调试和综合性能参数诊断,用于评价激光系统出光性能以及远场光斑可聚焦的能力。针对接近衍射极限光束质量β因子测量过程中被测光斑在面阵相机上所占的像素点太少等缺陷,研究了采... 详细信息

高能激光光束质量β因子测量装置主要用于强激光系统状态调试和综合性能参数诊断,用于评价激光系统出光性能以及远场光斑可聚焦的能力。针对接近衍射极限光束质量β因子测量过程中被测光斑在面阵相机上所占的像素点太少等缺陷,研究了采用聚焦显微放大与高精度扫描狭缝相结合的光束质量β因子测量方法,并对相关方案进行了分析计算。此外还设计了采用固定像差元件及平行光管光源组合的激光光束质量β因子测量结果验证方案,对研制的高能激光光束质量β因子测量装置进行了不确定度分析,测量不确定度优于10%。

关键词：高能激光 β因子测量方法显微放大扫描狭缝

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Reinforced SnO2 tensile-strength and“buffer-spring”interfaces for efficient inorganic perovskite solar cells

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Carbon Energy 2024年第6期6卷 282-291页

作者： yuanyuan Zhao Lei Gao Qiurui Wang Qiang Zhang Xiya Yang Jingwei Zhu Hao Huang Jialong duan Qunwei Tang College of Mechanical and Electronic Engineering Shandong University of Science and TechnologyQingdaoChina Institute of New Energy Technology College of Information Science and TechnologyJinan UniversityGuangzhouChina College of Materials Science and Engineering Sichuan UniversityChengduChina Guangxi Key Laboratory of Processing for Non-Ferrous Metals and Featured Materials School of ResourcesEnvironment and MaterialsGuangxi UniversityNanningChina Institute of Carbon Neutrality College of Chemical and Biological EngineeringShandong University of Science and TechnologyQingdaoChina

Suppressing nonradiative recombination and releasing residual strain areprerequisites to improving the efficiency and stability of perovskite solar cells(PSCs).Here,long-chain polyacrylic acid(PAA)is used to reinforce SnO_(2)film and passivate SnO_(2)defects,forming a structure similar to“reinforcedconcrete”with high tensile strength and fewer ***,PAA is also introduced to the SnO_(2)/perovskite interface as a“buffer spring”torelease residual strain,which also acts as a“dual-side passivation interlayer”to passivate the oxygen vacancies of SnO_(2)and Pb dangling bonds in *** a result,the best inorganic CsPbBr_(3)PSC achieves a championpower conversion efficiency of 10.83%with an ultrahigh open-circuit voltageof 1.674 *** unencapsulated PSC shows excellent stability under 80%relative humidity and 80℃over 120 days.

关键词： charge recombination defect passivation inorganic perovskite solar cells interfacial modification strain relaxation

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