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Energy Conversion and Transmission of Electric power Generation through Water Evaporation

Journal of thermal science 2025年第2期34卷 413-428页

作者： CHEN Liang WANG Lu WANG Xinyi ZHANG Bo LI Zhen Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Department of Engineering MechanicsTsinghua UniversityBeijing100084China

Water is a recyclable resource and the largest energy carrier on *** hydropower generation technologies hold great promise for the ***,there is a lack of evaluation standards for power generation ***,the mechanism of hydrovoltaic power generation lacks systematic *** this study,a thermodynamic analysis method about hot and humid air energy conversion based on the principle of hydropower generation is *** author's knowledge,it is the first time that the maximum available energy of hydropower generation is analyzed by exergy and parametric *** greater the difference,the higher the available ***,a series of experiments were conducted to explore the power generation device materials,structural composition,and structural parameters,further clarifying the principle of electricity ***,the influence of temperature and relative humidity on the power generation performance was also *** increase in temperature can effectively increase the output electrical performance of the power *** open-circuit voltage and short-circuit current of water evaporation power generation with Al_(2)O_(3)nanoparticles are higher than 2.5 V and 150 nA *** analysis,we propose relevant application strategies to provide theoretical and practical support for the development of green energy.

关键词： exergy analysis green energy new hydropower generation flexible power generation devices

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Multi-objective optimization of laser perforated fuel filter parameters based on artificial neural network and genetic algorithm

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Particuology 2025年第1期96卷 57-70页

作者： Yifan Wang Tianyi Zhang Lei Chen Wenquan Tao Key Laboratory of Thermo-Fluid Science and Engineering MOESchool of Energy and Power EngineeringXi'an Jiaotong UniversityXi'an710049China

In precise fuel circuit systems, the filtration of particulate impurities seriously affects the efficiency and service life of various components. For filtration process intensification of high-pressure fuel laser perforated filters, the two-phase flow characteristics in filters is studied. The size, position and number of filtration holes are taken as optimization variables, and take the filtration efficiency and flow pressure drop as optimization objectives. Computational fluid dynamics (CFD) is used to simulate the two-phase motion of continuous phase and discrete particles in a periodic unit. Artificial neural networks (ANN) are utilized for objectives prediction, and the NSGA-II genetic algorithm is employed for multi-objective optimization, resulting in the Pareto front solution set. Furtherly, the reasonable solution is selected by introducing TOPSIS to ensure that two optimization indexes are relatively smaller and balanced. The optimized filter element scheme allows the filter to have a pressure drop of less than 3.2 MPa under high pressure and a filtration efficiency of over 80% for spherical particle impurities with a diameter of 5 μm or more.

关键词： Fuel filter Multiphase flow Neural network Genetic algorithm Multi-objective optimization Particle

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An Implicit Scheme for Least-Square Gradient in Coupled Algorithm

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International Journal for Numerical Methods in Fluids 2025年第5期97卷 795-819页

作者： Li, Zhao-Ren Ou, Guo-Hui Chen, Li Ji, Wen-Tao Tao, Wen-Quan Key Laboratory of Thermo-Fluid Science and Engineering of MOE School of Energy and Power Engineering Xi'an Jiaotong University Xi'an China

In this paper, an implicit scheme that uses the least-square method to compute the pressure gradient term in the momentum equation, mainly for coupled algorithm was proposed. Accurate computation of the pressure gradient is crucial in computational fluid dynamics, directly influencing the precision of calculation results. The least-square gradient can reach unconditional second-order accuracy in the finite volume method. Currently, the least-square gradient method is predominantly employed in segregated algorithms, primarily utilizing explicit schemes that are not applicable to coupled algorithms. The scarcity of high-accuracy schemes for computing pressure gradients in coupled algorithms underscores a significant research gap. It contributes by presenting a derivation of an implicit scheme for the least-square gradient, complemented by an extensive discussion on boundary treatment methods. The efficacy of proposed least-square method through comparative analysis involving the Green-Gauss method, as well as benchmarking against existing literature or analytical solutions across distinct cases. The findings demonstrate that, in the majority of cases, the least-square method offers superior accuracy and convergence rates compared with the Green-Gauss method. © 2025 John Wiley & Sons Ltd.

关键词： coupled algorithm least-square method pressure gradient

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Baseline-free wavelength modulation spectroscopy based on cepstral analysis

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Optics Express 2025年第8期33卷 17645-17662页

作者： Wang, Zhenhai Zhu, Ning Wang, Weitian Chao, Xing Center for Combustion Energy Department of Energy and Power Engineering Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Tsinghua University Beijing100084 China

This paper demonstrates what we believe to be a new WMS m-FID technique based on cepstral analysis, incorporating wavelength modulation spectroscopy (WMS) with a modified form of the time-domain molecular free-induction decay (m-FID) signal. Detailed theoretical framework of the WMS m-FID technique, as well as the fitting routine, has been investigated. The proposed WMS m-FID technique is first validated through a static CO gas cell experiment using the CO R(9) absorption line near 2179.7719 cm−1. The fitting error between the measured and best-fit m-FID signals is less than 1.0 %, with integrated absorbance area of relative uncertainty 0.17 %. Time-resolved measurements of CO over a 6-second purge period demonstrate the reliability and robustness of the proposed WMS m-FID approach in comparison with direct absorption spectroscopy (DAS) and WMS-2f/1f techniques. The demonstration of the proposed WMS m-FID approach is further carried out in a premixed CH4/Air laminar flame of a flat-flame burner. The relative fitting residuals between the measured and best-fit m-FID signals remain below 4.0 %, yielding T = 1763 K and XH2O = 16.58 % at HAB = 7 mm, with a temperature uncertainty of 30 K and absolute H2O concentration uncertainty of 0.65 %. The average temperature difference between the WMS m-FID and WMS-2f/1f techniques is within 18.0 K (2O concentration difference is within 0.4 % (rd-order peak (τ ≥ ∼5.7 ns) and the 4th-order peak (τ ≥ ∼7.7 ns), with deviations of 2.7 % and 4.4 % from the entire m-FID signal fitting, respectively. Both the static gas-cell and high-temperature flat-flame demonstrations indicate that the proposed WMS m-FID technique enables quantitative, accurate, and baseline-free measurements. It is envisioned that the WMS m-FID technique can be an effective solution for achieving baseline-free, quantitative, in situ monitoring in practical combustion environments. © 2025 Optica Publishing Group under the terms of the Optica Open Access Publishing Agr

关键词： Absorption spectroscopy

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Modeling and Performance Analysis on an Integrated System Combining Supercritical Carbon Dioxide Brayton Cycle with Leakage Feedback Utilizing a Heat Pump or Direct Compression

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Journal of engineering for Gas Turbines and power 2025年第10期147卷 101011页

作者： Qi, Yinke Ma, Xiaofeng Jiang, Peixue Zhu, Yinhai Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Beijing Key Laboratory of CO2 Utilization and Reduction Technology Department of Energy and Power Engineering Tsinghua University Beijing100084 China

CO2 leakage due to the coexistence of pressure differentials and clearances within the integrated turbine-Alternator-compressor (TAC) of the kW-level sCO2 Brayton cycle is a key issue affecting cycle efficiency and long-Term stable operation. To analyze the impact of leakage and feedback, this study examined the integrated system of the sCO2 Brayton cycle with leakage feedback and compared the system performance differences between heat pump feedback and direct compression feedback. Thermodynamic models for the Brayton cycle and feedback unit were established, and the effects of varying key parameters were analyzed. A genetic algorithm was employed to further optimize the system. The selection suggestion charts for the feedback unit were obtained. It is recommended to choose a direct compression feedback unit for conditions with a cavity pressure higher than 6.41 MPa, whereas a heat pump feedback unit is recommended for other conditions. The heat pump feedback unit has advantages particularly at high rotational speeds, low leakage factors, and low cavity pressures. The efficiency of the optimized integrated system is improved by up to 12.53%. The net power accounted for only 53.6% of the turbine output power, the main cycle compression power accounted for 32.1%, the TAC losses accounted for 10.7%, and the total compression power of the feedback unit accounted for 3.7%. Ignoring the internal leakage and losses of TAC can overestimate the power generation capacity of the Brayton cycle, resulting in it being only 79% of the ideal case after considering losses and power consumption. © 2025 American Society of Mechanical Engineers (ASME). All rights reserved.

关键词： Brayton cycle

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Ambient-freeze hybrid drying: A facile, low-cost synthesis method for composite silica aerogel with ideal formability and thermal insulation performance

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Ceramics International 2025年第10期51卷 12842-12852页

作者： Hu, Yang Tao, Jihao Nie, Yinan He, Chenbo Si, Qiaolin Sun, Chunlei Zhao, Xin Tang, Guihua MOE Key Laboratory of Thermo-Fluid Science and Engineering School of Energy and Power Engineering Xi'an Jiaotong University Xi'an710049 China

Due to the fragile characteristic of silica aerogel, it is difficult to achieve large-scale preparation of large-sized and multi-shaped silica aerogels through the simple and low-cost ambient drying method to meet the needs of various application fields. In this study, we present a novel approach that combines ambient and freeze drying methods to synthesize fiber composite silica aerogels with excellent formability and thermal insulation performance. Rock-wool fibers and TiO2/ZrO2 fibers produced by electrostatic spinning were employed to fabricate composite in various shapes. The rock-wool fiber composite aerogel exhibits high thermal insulation performance with a thermal conductivity of 0.0283 W m−1 K−1 at room temperature. The TiO2/ZrO2 fiber composite aerogel demonstrates a high specific surface area of 792.26 m2 g−1 and outstanding temperature resistance up to 800 °C. The Mie scattering simulations demonstrate that the TiO2/ZrO2 composite fibers exhibit high radiative shielding properties at high temperature and the measured thermal conductivity of the TiO2/ZrO2 fiber composite aerogel powder is 0.0538 W m−1 K−1 at 800 °C in an argon atmosphere. This study introduces a novel method for integrating silica aerogel with various types of fibers, expanding the potential applications of ambient drying aerogels. © 2025 Elsevier Ltd and Techna Group S.r.l.

关键词： thermal conductivity

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Effects of Operation Parameters on Heat Transfer in Tubular Moving Bed Heat Exchangers:A CFD-DEM Study

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Journal of thermal science 2025年第2期34卷 542-554页

作者： LU Weiqin LI Zhihan TANG Xueyu LIU Dinghe KE Xiwei ZHOU Tuo Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Department of Energy and Power EngineeringTsinghua UniversityBeijing100084China School of Transportation and Vehicle Engineering Shandong University of TechnologyJi’nan255049China College of Electrical and Power Engineering Taiyuan University of TechnologyTaiyuan030024China

Tubular moving bed heat exchangers(MBHEs)present inherent advantages for efficiently and stably recovering sensible heat from high-temperature granular *** this study,we introduce a viable and practical approach based on the combined approach of Computational Fluid Dynamics with Discrete Element Method(CFD-DEM)and employ it to conduct a comprehensive investigation into the effects of operation parameters on tubular *** parameters include inlet particle temperature(ranging from 500℃to 700℃),tube wall temperature(ranging from 50℃to 250℃),and particle descent velocity(ranging from 0.5 mm/s to 12 mm/s).Our analysis reveals that the heat radiation and gas film heat conduction predominantly govern the heat transfer process in the particle-fluid-wall system,collectively contributing to approximately 90%of the total heat flux of tube wall(Q_(w)^(simu)).The results indicate that increasing the inlet particle temperature and reducing the tube wall temperature intensify heat transfer by enlarging the temperature *** interestingly,Q_(w)^(simu) exhibits three distinct stages as particle descent velocity increases,including an ascent stage,a descent stage,and a stable ***,the simulation attempts suggest that the optimal descent velocity for maximizing Q_(w)^(simu) falls within the range of 1.3-2.0 mm/*** findings not only uncover the precise influence mechanisms of operation parameters on heat transfer outcomes but also offer valuable insights for heat transfer enhancement efficiency in MBHE system.

关键词： tubular moving bed heat exchangers heat transfer operation parameters CFD-DEM heat transfer enhancement

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Machine learning-assisted fluorescence visualization for sequential quantitative detection of aluminum and fluoride ions

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Journal of Environmental sciences 2025年第3期149卷 68-78页

作者： Qiang Zhang Xin Li Long Yu Lingxiao Wang Zhiqing Wen Pengchen Su Zhenli Sun Suhua Wang School of Environmental Science and Engineering Guangdong University of Petrochemical TechnologyMaoming 525000China MOE Key Laboratory of Resources and Environmental System Optimization College of Environmental Science and EngineeringNorth China Electric Power UniversityBeijing 102206China

The presence of aluminum(Al^(3+))and fluoride(F^(−))ions in the environment can be harmful to ecosystems and human health,highlighting the need for accurate and efficient *** this paper,an innovative approach is presented that leverages the power of machine learning to enhance the accuracy and efficiency of fluorescence-based detection for sequential quantitative analysis of aluminum(Al^(3+))and fluoride(F^(−))ions in aqueous *** proposed method involves the synthesis of sulfur-functionalized carbon dots(C-dots)as fluorescence probes,with fluorescence enhancement upon interaction with Al^(3+)ions,achieving a detection limit of 4.2 nmol/***,in the presence of F^(−)ions,fluorescence is quenched,with a detection limit of 47.6 nmol/*** fingerprints of fluorescence images are extracted using a cross-platform computer vision library in Python,followed by data ***,the fingerprint data is subjected to cluster analysis using the K-means model from machine learning,and the average Silhouette Coefficient indicates excellent model ***,a regression analysis based on the principal component analysis method is employed to achieve more precise quantitative analysis of aluminum and fluoride *** results demonstrate that the developed model excels in terms of accuracy and *** groundbreaking model not only showcases exceptional performance but also addresses the urgent need for effective environmental monitoring and risk assessment,making it a valuable tool for safeguarding our ecosystems and public health.

关键词： Machine learning Aluminum ion detection Fluorine ion detection Fluorescence probe K-means model

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Study of Multiphase Flow in Ultrafine Powder Stirred Mill Based on CFD-DEM 4th

Study of Multiphase Flow in Ultrafine Powder Stirred Mill Ba...

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4th International Conference on Mechanical Design and Simulation, MDS 2024

作者： Ge, Jingxu Huo, Chaoxia Wang, Lin Zheng, Jin Li, Guojun Key Laboratory of Thermal Fluid Science and Engineering of MOE Faculty of Energy and Power Engineering Xi’an Jiaotong University 28 Xianning West Road Shaanxi Xi’an China Xi’an Thermal Power Research Institute Co. Ltd Shaanxi Xi’an China

ISBN: (纸本)9789819778867

The stirred media mill with pin-type rotor structure is one of the important equipment for manufacturing superfine powder. The CFD-DEM method is used to simulate the solid and liquid flow in the stirred mill. The velocity, collision and energy in the grinding chamber were analysed. The results show that the velocity gradient near the wall of the cylinder and agitator is large, and the velocity gradient near the cover plate on both sides is small, and the distribution of solid particles with high velocity in the grinding chamber is small;the particle distribution in the grinding cavity is not uniform, showing a tendency to pile up to the cover plate on both sides;the total energy per particle in the area near the agitator is much higher than that of the cover plate area on both sides, and the area near the agitator is the effective grinding area. © The Author(s) 2025.

关键词： Multiphase flow

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Superhydrophobic ceramic membrane coupled with a biphasic solvent for efficient CO_(2)capture

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Green Energy & Environment 2025年第4期10卷 834-844页

作者： Kaili Xue Zhen Chen Xiaona Wu Heng Zhang Haiping Chen Junhua Li State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing100084China Beijing Key Laboratory of Pollutant Monitoring and Control in Thermoelectric Production Process School of EnergyPower and Mechanical EngineeringNorth China Electric Power UniversityBeijing102206China MOE Key Laboratory of Resources and Environmental Systems Optimization College of Environmental Science and EngineeringNorth China Electric Power UniversityBeijing102206China

An innovative strategy was proposed by integration of membrane contactor(MC)with biphasic solvent for efficient CO_(2) capture from flue *** accessible fly ash-based ceramic membrane(CM)underwent hydrophobic modification through silane grafting,followed by fluoroalkylsilane decoration,to prepare the superhydrophobic membrane(CSCM).The CSCM significantly improved resistance to wetting by the biphasic solvent,consisting of amine(DETA)and sulfolane(TMS).Morphological characterizations and chemical analysis revealed the notable enhancements in pore structure and hydrophobic chemical groups for the modified *** of wetting/bubbling behavior based on static wetting theory referred the liquid entry pressure(LEP)of CSCM increased by 20 kPa compared to pristine *** with traditional amine solvents,the biphasic solvent presented the expected phase *** experiments demonstrated that the CO_(2) capture efficiency of the biphasic solvent increased by 7%,and the electrical energy required for desorption decreased by 32%.The 60-h continuous testing and supplemental characterization of used membrane confirmed the excellent adaptability and durability of the *** study provides a potential approach for accessing hydrophobic ceramic membranes and biphasic solvents for industrial CO_(2) capture.

关键词： Carbon capture Membrane contactor Hydrophobic modification Membrane wetting Biphasic solvent

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