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Performance and Sizes of sCO_(2)Multistage Axial Compressors at Various power Capacities

Journal of Thermal Science 2025年第2期34卷 352-373页

作者： WANG Tianze XU Jinliang ZHENG Haonan QI Jianhui Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy Utilization North China Electric Power UniversityBeijing100026China Key Laboratory of Power Station Energy Transfer Conversion and System(North China Electric Power University) Ministry of EducationBeijing102206China School of Energy and Power Engineering Shandong UniversityJi’nan250061China

The supercritical carbon dioxide(sCO_(2))cycle can be powered by traditional as well as clean *** help users obtain more accurate results than the literatures with pre-set compressor efficiency,we proposed a complete model to establish a link between the performance,sizes of compressors and parameters such as power W_(C),inlet temperature T_(in),inlet pressure P_(in)and pressure ratioε.Characteristic sizes of compressors l_(c),profile loss Y_(p)and clearance loss Ycl are all proportional to powers of W_(C)with powers of 0.5,-0.075 and-0.5 to 0 respectively;the scaling laws are constant in the range of capacities from 20 MW to 200 *** compressor isentropic efficiencyη_(tt)grows as the W_(C)increases,and the curves become *** efficiency improves over the full power range when the speed is changed from standard speed to the optimal speed;theη_(tt)curves turn soft as the n *** the P_(in)and T_(in)approach the critical point,theη_(tt)*** efficiency follows a parabolic curve as theεincreases,this parabolic distribution results from the tradeoff between the change in losses and the pressure distribution of ***η_(tt)versus P_(in),T_(in)andεrelations are similar at various capacities because of insignificant changes in the distribution of *** efficiency maps facilitate the estimation of system performance,while scaling law for irreversible losses and characteristic lengths,along with constant criterion analyses,aid in comprehending the characteristics of compressors across various capacities.

关键词： sCO_(2)cycle compressor efficiency irreversible losses scaling laws

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Graph neural network-driven prediction of high-performance CO_(2)reduction catalysts based on Cu-based high-entropy alloys

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Chinese Journal of Catalysis 2025年第4期71卷 197-207页

作者： Zihao Jiao Chengyi Zhang Ya Liu Liejin Guo Ziyun Wang International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi’an Jiaotong UniversityShaanxi 710049China School of Chemical Sciences University of AucklandAuckland 1010New Zealand

High-entropy alloy(HEA)offer tunable composition and surface structures,enabling the creation of novel active sites that enhance catalytic performance in renewable energy ***,the inherent surface complexity and tendency for elemental segregation,which results in discrepancies between bulk and surface compositions,pose challenges for direct investigation via density functional *** address this,Monte Carlo simulations combined with molecular dynamics were employed to model surface segregation across a broad range of elements,including Cu,Ag,Au,Pt,Pd,and *** analysis revealed a trend in surface segregation propensity following the order Ag>Au>Al>Cu>Pd>*** capture the correlation between surface site characteristics and the free energy of multi-dentate CO_(2)reduction intermediates,a graph neural network was designed,where adsorbates were transformed into pseudo-atoms at their centers of *** model achieved mean absolute errors of 0.08–0.15 eV for the free energies of C_(2)intermediates,enabling precise site activity *** indicated that increasing the concentration of Cu,Ag,and Al significantly boosts activity for CO and C_(2)formation,whereas Au,Pd,and Pt exhibit negative *** screening stable composition space,promising HEA bulk compositions for CO,HCOOH,and C_(2)products were predicted,offering superior catalytic activity compared to pure Cu catalysts.

关键词： Density functional theory Machine learning CO_(2)reduction High entropy alloys Graph neural network

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BiOI晶体缺陷工程提升光催化CO2到C2产物转化性能（英文）

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Science China Materials 2025年第5期68卷 1561-1569页

作者：黄富霞刘一菲王峰刘亚郭烈锦 International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi'an Jiaotong University

BiOI材料在光催化CO2还原领域展现出巨大潜力,但其较弱的CO2的活化能力与较差的载流子分离效率严重制约了光催化转化效率.本研究通过构建富含丰富晶体缺陷的BiOI基光催化剂有效地提高了其光催化性能.结合X射线衍射、拉曼、和高分辨透射... 详细信息

BiOI材料在光催化CO2还原领域展现出巨大潜力,但其较弱的CO2的活化能力与较差的载流子分离效率严重制约了光催化转化效率.本研究通过构建富含丰富晶体缺陷的BiOI基光催化剂有效地提高了其光催化性能.结合X射线衍射、拉曼、和高分辨透射电子显微镜表征,证实了BiOI-LD和BiOI-TC催化剂中分别存在晶格畸变和孪晶结构缺陷.紫外-可见光谱、微孔与化学吸附分析,以及光致发光光谱表征结果表明,晶体缺陷的引入显著增强了光催化剂的光吸收能力、CO2吸附能力、载流子传输效率及寿命.电子顺磁共振光谱进一步证实BiOI-TC中超氧自由基的生成量显著提升,表明晶体缺陷构筑有效增强了催化剂表面反应活性.因此, BiOI-TC催化剂实现了6.2μmol g-1h-1的CH3CH2OH生成速率,且选择性达到100%.通过原位FTIR研究识别了生成CH3CH2OH的关键中间体（*CO、*COCO、*CHO和*CH2）,并揭示BiOI-LD中C2H6的生成与*CH3中间体的形成密切相关.

关键词： photocatalysis CO2 reduction BiOI crystal defects CH3CH2OH C2H6

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Performance comparison investigation on different pulse tube position heat pumps with power recovery displacer

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International Journal of Refrigeration 2025年 176卷 1-16页

作者： Zhu, Shenglin Chen, Xi Zhu, Yifan Qi, Yingxia School of Energy and Power Engineering University of Shanghai for Science and Technology 516 Jungong Road Shanghai200093 China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering University of Shanghai for Science and Technology 516 Jungong Road Shanghai200093 China

Spacecraft waste heat is dissipated into space primarily by radiation. To improve the heat dissipation efficiency of spacecraft radiators in high-temperature environments and reduce heat wastage in spaceflight thermal control systems, thermoacoustic heat pumps (TAHP) are considered a viable method for increasing radiator cooling temperatures and recovering waste heat. In this study, one-dimensional simulations are used to optimize the geometrical parameters of the 100-watt work recovery thermoacoustic heat pump (WRTAHP) for various pulse tube positions. The performances of the two systems are compared at a cold-end temperature of 293 K and a hot-end temperature of 353 K. The results reveal that a heating capacity of 256 W with a relative Carnot efficiency of 35.01 % is achieved for the pulse tube front-type thermoacoustic heat pump (FTTAHP), whereas the pulse tube back-type thermoacoustic heat pump (BTTAHP) obtains a heating capacity of 225 W with a relative Carnot efficiency of 30.59 %. As the cold-end temperature decreases, the coefficient of performance is reduced for FTTAHP, while the performance of BTTAHP shows a substantial improvement. At a cold end temperature of 233 K and a hot-cold end temperature difference of 60 K, a heating capacity of 268 W with a relative Carnot efficiency of 50.57 % is achieved for BTTAHP. Furthermore, the heating capacity of the BTTAHP is not significantly increased by adopting the active phase adjustment structure. In summary, the FTTAHP is suitable for spacecraft radiator applications and avoids high temperatures affecting compressor operation, whereas the BTTAHP is better suited for low-temperature heating. © 2025 Elsevier Ltd and IIR

关键词： Waste heat utilization

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Concurrently Boosting Activity and Stability of Oxygen Reduction Reaction Catalysts via Judiciously Crafting Fe-Mn Dual Atoms for Fuel Cells

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Nano-Micro Letters 2025年第4期17卷 275-289页

作者： Lei Zhang Yuchen Dong Lubing Li Yuchuan Shi Yan Zhang Liting Wei Chung-Li Dong Zhiqun Lin Jinzhan Su International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi’an Jiaotong UniversityXi’an 710049People’s Republic of China Department of Physics Tamkang UniversityNew Taipei CityTaiwan 25137People’s Republic of China Department of Chemical and Biomolecular Engineering National University of SingaporeEngineering Drive 4Singapore 117585Singapore

The ability to unlock the interplay between the activity and stability of oxygen reduction reaction(ORR)represents an important endeavor toward creating robust ORR catalysts for efficient fuel ***,we report an effective strategy to concurrent enhance the activity and stability of ORR catalysts via constructing atomically dispersed Fe-Mn dualmetal sites on N-doped carbon(denoted(FeMn-DA)-N-C)for both anion-exchange membrane fuel cells(AEMFC)and proton exchange membrane fuel cells(PEMFC).The(FeMn-DA)-N-C catalysts possess ample dual-metal atoms consisting of adjacent Fe-N_(4)and Mn-N_(4)sites on the carbon surface,yielded via a facile doping-adsorption-pyrolysis *** introduction of Mn carries several advantageous attributes:increasing the number of active sites,effectively anchoring Fe due to effective electron transfer to Mn(revealed by X-ray absorption spectroscopy and density-functional theory(DFT),thus preventing the aggregation of Fe),and effectively circumventing the occurrence of Fenton reaction,thus reducing the consumption of ***(FeMn-DA)-N-C catalysts showcase half-wave potentials of 0.92 and 0.82 V in 0.1 M KOH and 0.1 M HClO_(4),respectively,as well as outstanding *** manifested by DFT calculations,the introduction of Mn affects the electronic structure of Fe,down-shifts the d-band Fe active center,accelerates the desorption of OH groups,and creates higher limiting *** AEMFC and PEMFC with(FeMn-DA)-N-C as the cathode catalyst display high power densities of 1060 and 746 mW cm^(-2),respectively,underscoring their promising potential for practical *** study highlights the robustness of designing Fe-containing dual-atom ORR catalysts to promote both activity and stability for energy conversion and storage materials and devices.

关键词： Doping-adsorption-pyrolysis Dual-atom catalysts Oxygen reduction reaction Fuel cells

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Thermodynamic and environmental analysis of the hydrogen and combustible gas production in supercritical water partial oxidation system of coal

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Energy 2025年 326卷

作者： Li, Yifeng Xing, Guowei Liu, Shi Guo, Shenghui Ge, Zhiwei Guo, Liejin State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

Supercritical water partial oxidation (SCWPO) is an eco-friendly coal treatment technology that lowers the temperature needed for complete coal gasification, promotes hydrogen output, enables targeted regulation of gaseous product composition, and eliminates gaseous pollutants. Current researches mainly focus on experiments and numerical simulations, with limited exploration in thermodynamics. The present study establishes an auto-thermal SCWPO cogeneration system for Hongliulin coal, employs sensitivity analysis to refine system parameters, and utilizes Life Cycle Assessment to evaluate the environmental impact of the hydrogen production system. When the outlet temperature of the SCWPO reactor increases, the preheating water flow and equivalence ratio (ER) enhance, the fraction of H2 in the gas product rises;conversely, the fraction of the combustible gas (CH4+CO + H2) rises. The SCWPO system can be precisely tailored to yield high-purity hydrogen or combustible gas by modulating the amount of oxygen input. The system of combustible gas production is capable of generating 241.67 GJ h−1 of energy and attaining a cold gas efficiency of 81.62 % when the ER is 0.25. The hydrogen production system can generate 1004.38 kg h−1 of H2 and 206 t h−1 of steam at 0.5 MPa and 150 °C for an ER of 0.6. The optimized hydrogen production system achieved 90.97 % energy efficiency and 59.33 % exergy efficiency. The standard Global Warming Potential through carbon capture technology is 0.087 (kg H2)−1. The system developed in this paper benefits the industrial application of SCWPO and the optimization of subsequent processes. © 2025 Elsevier Ltd

关键词： River pollution

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A multi-physics model-based approach for macro-structured surface design to enhance heat transfer in R410A flash spray cooling systems

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International Journal of Heat and Mass Transfer 2025年 247卷

作者： Ye, Ying-Dong Lin, Xiang-Wei Zhou, Zhi-Fu Liu, Maochang Chen, Bin Lu, Youjun Jing, Dengwei State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

Refrigerant flash spray cooling, which offers high heat flux dissipation at low temperatures, holds significant potential for thermal management of high-power electronic devices. While surface structure design can further amplify heat transfer performance, the lack of systematic methodologies to address the complexities of spray cooling has hindered progress. This study establishes a multi-physics computational framework that couples two-phase flash spray dynamics, liquid film heat transfer, and solid heat conduction to systematically optimize macro-structured surfaces. After validating the model against experimental data, the effects of surface geometry (flat, square, straight and pyramid fins) and dimensional parameters on cooling performance were analyzed. The pyramid structure demonstrated superior performance, achieving a 9 K reduction in surface temperature and a 70 % increase in effective heat transfer coefficient compared to the flat surface. Quantitative analysis revealed that optimal macro-structured design hinges on maximizing effective heat transfer area while ensuring uniform liquid film distribution via controlled droplet dynamics. Further parametric studies on nine pyramid geometries identified a base length of 1 mm and height-to-edge ratio of 0.7 as the optimal configuration, balancing heat transfer enhancement and manufacturing costs through a newly proposed Composite Heat Transfer Factor (CHTF). This work provides a mechanistic framework for designing enhanced surfaces in spray cooling systems, bridging critical gaps in both theoretical understanding and engineering application. © 2025 Elsevier Ltd

关键词： Film cooling

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Effects of methanol and its cracked gas on ammonia consumption and NO x emission under high pressure

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International Journal of Hydrogen Energy 2025年 136卷 491-500页

作者： Geyuan Yin Shujie Shen Haochen Zhan Erjiang Hu Zuohua Huang State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an People's Republic of China

The mole fraction profiles for NH 3 /syngas were measured at 5.0 MPa and different blending ratios and compared with NH 3 /methanol to understand the effects of methanol and its cracked gas on ammonia oxidation and micro-species behavior. A kinetic model proposed in our previous work is validated against the measured data. The model demonstrates remarkable accuracy in predicting the concentration profiles of NH 3 and NO x under all conditions. Moreover, a superior performance of methanol control is found at low temperatures, while syngas has a better performance at high temperatures. The onset temperature of methanol is lower than that of syngas. When the temperature reaches 950 K, H 2 can provide more active OH than methanol and accelerate the ammonia consumption through the reaction cycle. Moreover, methanol triggers NO formation at 50 K lower than syngas, and the peak molar concentration of NO is lower than that of syngas at high blending ratios. At a substitution ratio of 50 %, NO generated by an ammonia-methanol mixture exhibits an “N”-shaped trend, while it monotonically increases with temperature with syngas blending. The peak concentrations of N 2 O with methanol are higher than those from syngas, especially at substitution ratios of 10 % and 25 %.

关键词： Nitrogen oxides

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NUMERICAL STUDY OF THE EFFECT OF PERIODIC WAKE ON FILM COOLING EFFECTIVENESS ON A PLATE

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Thermal Science 2025年第2期29卷 1197-1206页

作者： Shi, Liuliu Fan, Haobo Chen, Eryun School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering Shanghai China

The research presented in this paper is devoted to exploring the influence of up-stream periodic wake on the film cooling effectiveness on a downstream plate. This investigation is carried out through rigorous numerical simulations utilizing a ded-icated simulation model. The model was developed to examine the impact of up-stream periodic wake on film cooling performance across varying blowing ratios (M = 0.3, 0.5, and 1.0) and wake sweeping frequencies (10 Hz, 20 Hz, and 40 Hz). Comparative analyses are conducted with a baseline scenario involving a constant jet without wake. The objective of these analyses is to provide a deeper understand-ing of the mechanisms through which upstream wake influences film cooling per-formance, ultimately shedding light on the flow characteristics and cooling effec-tiveness of film cooling under sweeping wakes. © 2025 Published by the Vinča Institute of Nuclear Sciences, Belgrade, Serbia.

关键词： blowing ratio film cooling gas turbine wake

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Numerical study of specific C-shaped heat exchanger using porous medium and coarse mesh coupling method

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International Journal of Thermal Sciences 2025年 210卷

作者： He, Shaopeng Wang, Shiqi Wang, Mingjun Tian, W.X. Qiu, S.Z. Su, G.H. State Key Laboratory of Multiphase Flow in Power Engineering School of Nuclear Science and Technology Xi'an Jiaotong University Xi'an710049 China

Porous medium method is an effective simplified approach for the heat exchanger simulation when the numerous tubes and complex structures bring unacceptable computational resources to full-scale simulation. However, for the specific C-shaped heat exchanger, the tube side resistance and flow distribution characteristics that significantly affects the heat transfer and natural circulation performance cannot be obtained by the traditional porous medium method coupled with the one-dimensional node model for tube side. It is urgent to develop a new coupling method that can not only simplify modeling and calculation, but also obtain tube side high-resolution flow heat transfer characteristics. This study presents a novel calculation method which couples the porous medium mesh and the tube side coarse mesh. The coupling method was then applied to a typical C-shaped passive residual heat removal heat exchanger (PRHR HX), which is significant to the stable operation and the mitigation of accident conditions in the nuclear power plant. The coupling calculation method was validated against the full-scaled simulation and data from scaled-down experiment. The average relative error of heat transfer power is 2.1 % under steady state conditions. Under transient conditions, the average absolute error of the fluid temperature and wall temperature are less than 6 K. Then the 3D thermal-hydraulic characteristics of PRHR HX was studied. Owing to a greater gravitational pressure head, the mass flow rates in the extended tubes surpass those in the shorter tubes by a relative deviation of 27.4 %. The upper horizontal tube's heat exchange capacity constitutes approximately 70 % of the total power, leading to enhanced natural circulation. The outlet temperatures from various tubes tend to equalize. The boiling area gradually extended down along the heat transfer tubes. Our work would present an innovative calculation method to the numerical study and design optimization of the C-shaped heat

关键词： Nuclear power plants

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