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SSRN 2024年

作者： Wang, Cui Jin, Hui School of Water and Environment Chang'an University Xi’an710054 China Key Laboratory of Subsurface Hydrology and Ecological Effect in Arid Region of the Ministry of Education Chang'an University Xi’an710054 China Key Laboratory of Eco-hydrology and Water Security in Arid and Semi-arid Regions of Ministry of Water Resources Chang’an University Xi’an710054 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi’an710049 China Ministry of Education of China Chongqing University Chongqing400044 China

Biomass energy is renewable and rich in the world, providing a solution for the shortage in fossil fuel and serious environmental pollution. Proposing efficient utilization method of biomass waste demands urgent attention. Supercritical water gasification (SCWG) process is a potential technology. In this work, a poly-generation system based on SCWG was developed to convert biomass waste to gas, biochar, heat and electricity. Firstly, mass, energy, and exergy flow were calculated at the typical condition. Subsequently, impact of various operating parameters on the hydrogen-rich syngas yield, generated electricity, thermodynamic performance was investigated. The result demonstrated that the exergy loss primarily occurred on cooler, reactor, heat exchanger and preheater, accounting for more than 90% of total exergy loss, arising from irreversible reaction, heat transfer and heat dissipation. Higher temperature, biomass concentration and preheated water exerted a positive effect for hydrogen-rich gas production and supplied heat energy, while these parameters were disadvantageous to exergy efficiency. Biochar energy was affected by biomass concentration. Energy efficiency increased with preheated water quantity and biomass concentration rising, and impact of biomass concentration was more significant. Conversely, evaluated gasification temperature displayed an adverse effect on energy efficiency. The maximal exergy efficiency reached 58.3% at 550℃, 33%, 900 kg·h-1. © 2024, The Authors. All rights reserved.

关键词： Biomass

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pH-Triggered Hydroxylated Surface with Rapid Hydroxyl Radical Generation Boosts Efficient Noble-Metal-Free Pilot-Scale Photoreforming of Lignocellulose for Hydrogen Production

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SSRN 2023年

作者： Liu, Feng Fu, Yiwei Lu, Kejian Wang, Shujian Wang, Biao Huang, Jie Yan, Xueli Zheng, Yiqun Guo, Liejin Liu, Maochang International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Shaanxi Xi’an710049 China School of Chemistry Chemical Engineering and Materials Jining University Shandong Qufu273155 China Suzhou Academy of Xi’an Jiaotong University Jiangsu Suzhou215123 China

Photocatalytic H2 prodcution from lignocellulosic biomass photoreforming is deemed to be a promising alternative to overall water splitting owing to its more sustainable and value-added oxidation half-reaction. However, an efficient lignocellulose photoreforming system toward H2 production, especially at the pilot scale, is scarce and exigent to date. Herein, we present a lignocellulose photoreforming system containing noble-metal-free particulate twinned Cd0.5Zn0.5S nanocatalyst, water, and lignocellulose, enabling an unprecedented H2 evolution activity with an apparent quantum yield of 12.74% at 400 nm. Subsequently, an outdoor 7.2-m2 compound parabolic concentrator-based reactor is developed to scale up this system to a practical level with a H/2 production rate of 615 mL h-1 under direct solar irradiation. We demonstrate that a pH-triggered hydroxylated surface over Cd0.5Zn0.5S nanotwins enables superior hole transfer and rapid hydroxyl radical generation by inducing favorable reaction kinetics/thermodynamics in alkaline solution. Our work thus provides a state-of-art example of pilot-scale system for the practical Hsub>2 production via lignocellulose photoreforming. © 2023, The Authors. All rights reserved.

关键词： Lignocellulose

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Research on a Poly-Generation System for Gas-Biochar-Heat-Electricity by Supercritical Water Gasification of Biomass Waste

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SSRN 2024年

Biomass energy is renewable and rich in the world, providing a solution for the shortage in fossil fuel and serious environmental pollution. Proposing efficient utilization method of biomass waste demands urgent attention. Supercritical water gasification (SCWG) process is a potential technology. In this work, a poly-generation system based on SCWG was developed to convert biomass waste to gas, biochar, heat and electricity. Firstly, mass, energy, and exergy flow were calculated at the typical condition. Subsequently, impact of various operating parameters, including gasification temperature, mass flowrate of preheated water, biomass concentration, on the hydrogen-rich syngas yield, generated electricity, thermodynamic performance of the system was investigated. The result demonstrated that the exergy loss primarily occurred on cooler, reactor, heat exchanger and preheater, accounting for more than 90% of total exergy loss under different conditions, arising from irreversible reaction, heat transfer and heat dissipation. Higher temperature, higher biomass concentration and more preheated water exerted a positive effect for hydrogen-rich gas production and supplied heat energy, while these parameters were disadvantageous to exergy efficiency. Biochar energy was primarily affected by biomass concentration. Energy efficiency increased with preheated water quantity and biomass concentration rising, and impact of biomass concentration was more significant. Conversely, evaluated gasification temperature displayed an adverse effect on energy efficiency. The maximal exergy efficiency reached about 58.3% at 550°C, biomass concentration of 33%, preheated water mass flowrate of 900 kg·h-1 © 2024, The Authors. All rights reserved.

关键词： Biomass

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A Thermal Calculation Model for Tubular Condensing Heat Exchanger

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SSRN 2023年

作者： Han, Lei Yang, Kaixuan Yang, Jiahui Li, Ruiyu Li, Yuhang Deng, Lei Che, Defu State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an710049 China Shanghai Power Equipment Research Institute Co. Ltd. Shanghai200240 China Shunde Institute of Inspection Guangdong Institute of Special Equipment Inspection and Research Foshan528300 China Xi’an Thermal Power Research Institute Co. Ltd. Xi’an710032 China

The condensing heat exchanger is commonly applied in various heat exchange systems. It can efficiently recover moisture and heat from the flue gas that contains water vapor. However, the convective-condensation heat transfer process is so complicated that no mature thermal calculation model is available. This study develops a thermal calculation model for the widely employed tubular condensing heat exchanger in industry. To characterize the degree of the heat and mass transfer, this study introduces two parameters, namely the sensible and latent heat transfer efficiencies of fin. The thermal calculations are conducted for the condensing heat exchangers reported in the literature to verify the proposed model by comparing it with the experimental data. The results show that the absolute error of the calculated sensible and latent heat transfer efficiencies is 0.0365 and 0.0268, respectively. A maximum difference of 5.2 K has been acquired between the measured and calculated values of the outlet temperature. The relative error of the condensate water flowrate is mostly within ±5.0% and ±10.0% under the bare-tube and finned-tube conditions, respectively, with a maximum deviation of 0.7 and 1.4 kg h-1. This study provides a general model for designing and optimizing various tubular condensing heat exchangers accurately. © 2023, The Authors. All rights reserved.

关键词： Mass transfer

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Microwave-assisted synthesis of bimetallic NiCo-MOF-74 with enhanced open metal site for efficient CO 2 capture

Environmental Functional Materials

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Environmental Functional Materials 2022年第3期1卷 253-266页

作者： Changwei Chen Mohammadreza Kosari Meizan Jing Chi He State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University Xi'an 710049 Shaanxi PR China Department of Chemical and Biomolecular Engineering Faculty of Engineering National University of Singapore 10 Kent Ridge Crescent 119260 Singapore Department of Chemistry Key Laboratory of Organic Optoelectronics & Molecular Engineering of Ministry of Education Tsinghua University Beijing PR China National Engineering Laboratory for VOCs Pollution Control Material & Technology University of Chinese Academy of Sciences Beijing 101408 PR China

Metal–organic frameworks (MOFs) containing two different inorganic metal nodes (known as bimetallic MOFs) could exhibit enhanced CO 2 adsorption compared to their monometallic counterparts. Herein, a series of bimetallic NiCo-MOF-74 synthesized by microwave-assisted method were investigated for CO 2 adsorption. It was revealed that narrow micropore channel with open metal site (OMS) of the bimetallic NiCo-MOF-74 influence CO 2 binding affinity and CO 2 /N 2 adsorption. The CO 2 uptake of Ni 1 Co 1 -MOF-74 at 0 °C and 1 bar (100 kPa) was 8.30 mmol g −1 which is higher than those of Ni-MOF-74 (3.99 mmol g −1 ), Ni 6 Co 1 -MOF-74 (3.62 mmol g −1 ), Ni 1 Co 6 -MOF-74 (6.40 mmol g −1 ) and Co-MOF-74 (5.03 mmol g −1 ). While this could be related to the high specific surface area of Ni 1 Co 1 -MOF-74, Ni 1 CO 2 -MOF-74 with relatively low specific surface areas still shows good CO 2 adsorption capacity up to 5.70 mmol/g, which is higher than those of adsorbents Ni-MOF-74, Ni 6 Co 1 -MOF-74 and Co-MOF-74, indicating that adsorption performance mainly relies on coordinated metals. Ni 1 Co 1 -MOF-74 showed remarkable recyclability performance, ranking selectivity of CO 2 /N 2 reach up to 34, and suitable isosteric heat (31–23 kJ mol −1 ), manifesting a great probability for industrial CO 2 capture. As revealed, incorporated Ni 2+ /Co 2+ nodes within Ni 1 Co 1 -MOF-74, which are acting as active and open sites for CO 2 capture, led to the synergetic effects comprising of micropores as well as dense dual-metal sites.

关键词： Bimetallic metal–organic frameworks NiCo-MOF-74 Microwave-assisted synthesis Open metal site CO 2 capture

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The Role of Particle-Vortex Interaction in Hydraulic Performance and Erosion Behavior of Semi-Open Centrifugal Pump: Effect of Particle Size

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SSRN 2023年

作者： Wang, Kai Liu, Hanyu Wang, Like Guo, Pengcheng Wang, Yueshe Yang, Junfeng State Key Laboratory of Eco-hydraulics in Northwest Arid Region Xi’an University of Technology No.5 Jinhua South Road Xi’an710048 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University No.28 Xianning West Road Xi’an710049 China Shaanxi Provincial Dongzhuang Water Conservancy Engineering Co. Ltd Xi’an713200 China

The interaction between the particle migration and vortex evolution aggravates the complexity of erosion on the flow components. In this work, the liquid-solid two-phase flow of semi-open centrifugal pump under different particle sizes is simulated based on the four-way coupling Euler-Lagrange method, in which the fluid-particle interaction and particle-particle interaction are taken into account. The interrelationship among vortex structure, particle migration and surface erosion behavior is revealed. The results show that the erosion area is mainly distributed in the blade leading edge, the pressure surface inlet edge and the hub. When the particle size is 0.1 mm and 0.3 mm, due to the good following characteristic of particles and the inhibition effect on tip leakage vortex, the particles are easy to impact the outlet edge of blade suction surface and the hub, which induce severe erosion. As the particle size decreases, the number of particles flowing into the tip clearance layer increases. Therefore, the frequent impact of particles on the tip leakage vortex leads to the breakup, separation and refusion of the vortex, which aggravates the flow instability. This paper provides a new insight into the hydraulic performance and erosion characteristics of semi-open centrifugal pump in terms of particle-vortex interaction. © 2023, The Authors. All rights reserved.

关键词： Particle size

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Verification and validation plus uncertainty quantification of heat transfer simulation for liquid metal in wire-wrapped rod assembly

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International Communications in Heat and Mass Transfer 2025年 165卷

作者： Liu, Zhenglong Zhong, Peiling Qiu, Hanrui Wang, Mingjun Tian, Wenxi Su, Guanghui State Key Laboratory of Multiphase Flow in Power Engineering Department of Nuclear Science and Technology Xi'an Jiaotong University Xi'an710049 China

A complete CFD best practice process is proposed, including Phenomena Identification and Ranking Table (PIRT), Verification and Validation (V&V), and Uncertainty Quantification (UQ). The heat transfer of liquid metal within a rod assembly under both normal and blocked conditions is used as an example to demonstrate the full CFD process. key flow and heat transfer phenomena are identified, and model sensitivity analyses are performed based on these phenomena. Turbulent Prandtl models, porous blockage models and different meshing strategies sensitivity analysis are conducted. Uncertainty quantification is performed. The discretization uncertainty is calculated using the Grid Convergence Index (GCI). The convergence orders are greater than unity for all cases except the fluid temperature in the blocked condition using meshing strategy 2. The input parameter uncertainty is estimated using finite difference. The model uncertainty is derived. Under normal condition, the model uncertainty of the wall and fluid temperatures are 2.88 K and 3.37 K, respectively. Under blocked condition, the model uncertainty of wall temperature is slightly higher than fluid temperature. The wall temperature uncertainty for strategies 1 and 2 are 8.46 K and 9.03 K, while the fluid uncertainty of strategy 1 and 2 are 3.57 K and 3.06 K, respectively. © 2025 Elsevier Ltd

关键词： Liquid metals

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Experimental Study of Air-Steam–Mixture Condensation Underneath Containment Vessel Surface

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Nuclear Science and engineering 2021年第8期195卷 838-852页

作者： Bing Tan W. X. Tian R. H. Chen S. Z. Qiu G. H. Su a Xi’an Jiaotong University School of Nuclear Science and Technology State Key Laboratory of Multiphase Flow in Power Engineering 28 Xianning West Road Xi’an 710049 Chinab South China University of Technology School of Electric Power Guangzhou 510640 China a Xi’an Jiaotong University School of Nuclear Science and Technology State Key Laboratory of Multiphase Flow in Power Engineering 28 Xianning West Road Xi’an 710049 China

Aiming at studying the condensate flow phenomenon and air-steam–mixture condensation heat transfer underneath a containment vessel surface, a test bench was constructed. The plate dimension was 1.5 × 0.6 m, with Carbozinc 11 coating on the surface, suspended in a pressure vessel with 2.5-m diameter and 4.5-m height. The air-steam mixture was condensed on an inclined plate through natural convection mode and jet mode. By observing flow behavior on the plate through a viewport, four basic regimes were obtained as the inclination angle gradually increased: droplet, droplet to rivulet transition, developed rivulet, and uniform film. During the experiment, we observed a steam atomization phenomenon; therefore, the model predicted better with the atomization effect considered. A simple formula from the condensation data is proposed when the air mole fraction is small. The error between the experimental results and the predicted data is within 25%.

关键词： Passive cooling system steam condensation flow regime new empirical correlation

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Rapid modeling of transient processes in hydrogen-blended natural gas pipelines featuring injection and withdrawal points

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International Journal of Hydrogen Energy 2025年

作者： Gong, Junhua Zhou, Chaoqun Wang, Yanxin Deng, Yajun Chen, Yujie Wang, Peng Yu, Bo Chen, Bin Yu, Zhipeng Wang, Bohong School of Mechanical Engineering Beijing Institute of Petrochemical Technology Beijing102617 China Changqing Oil and Gas Transportation Branch of Northwest Company of PipeChina Xingqing District Ningxia Yinchuan City750004 China PipeChina Engineering Technology Innovation Co.Ltd Tianjin300450 China School of Petroleum Engineering Yangtze University Wuhan430100 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China National & Local Joint Engineering Research Center of Harbor Oil & Gas Storage and Transportation Technology/Zhejiang Key Laboratory of Pollution Control for Port-Petrochemical Industry Zhejiang Ocean University Zhoushan316022 China

Blending hydrogen into natural gas pipelines enables the large-scale delivery and application of hydrogen, contributing to carbon emission reduction and promoting the transition to cleaner energy sources. Accurate and efficient predictions of transient processes in such pipelines are critical for effective management and operation. This study proposes a Fourier Neural Operator (FNO)-based model for the rapid prediction of transient processes in hydrogen-blended pipelines with injection and withdrawal points. The model is trained using numerical simulation data of pressure and flow dynamics, with initial conditions, boundary conditions, and the hydrogen blending ratio as inputs to predict hydraulic parameters along the pipeline over time. By optimizing data preprocessing and neural network hyperparameters, the model achieves high accuracy and efficiency in predicting hydraulic states. The FNO model achieves average Root Mean Squared Errors (RMSEs) of 1.06 × 10−3, 1.64 × 10−3, and 7.40 × 10−4 for pressure, flow rate, and density, respectively, with the Coefficient of Determination (R2) exceeding 0.99 for all three variables. Furthermore, the model demonstrates strong generalization capabilities, accurately predicting hydraulic states for pipeline topologies and scenarios beyond the training data. In these cases, the RMSE remains in the order of 10−3 or smaller. For a 100 km pipeline, the computational efficiency of the FNO model is at least 969 times higher than that of traditional numerical methods, with the maximum efficiency improvement reaching 5168 times as the number of pipeline cases simultaneously predicted increases. These results highlight the potential of the FNO model for real-time applications in hydrogen-blended natural gas pipeline management. © 2025 Hydrogen Energy Publications LLC

关键词： Mean square error

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Modeling and prediction of ultrasonic attenuations in liquid-solid dispersions containing mixed particles with Monte Carlo method

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Particuology 2019年第2期17卷 84-91页

作者： Jianfei Gu Fengxian Fan Yunsi Li Huinan Yang Mingxu Su Xiaoshu Cai Institute of Particle and Two-Phase Flow Measurement/Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering University of Shanghai for Science and Technology Shanghai 200093 China

We develop a theoretical model for predicting the ultrasonic attenuation in the liquid-solid system containing mixed particles. The ultrasonic attenuation coefficient is obtained by counting the number of phonons that reach the receiver. Using the Monte Carlo method (MCM), numerical simulations were performed to predict the ultrasonic attenuations with not only a single particle type but also monodisperse and polydisperse mixed particles. The simulation results for the systems with a single particle type were compared with various standard models. The results show that they agree well at relatively low particle volume concentrations (within 10%). For systems with mixed particles, the particle volume concentrati on was found to in crease to around 10%, and the variation of the ultrasonic attenuation agai nst the mixing ratio yields a nonlinear trend. Moreover, the ultrasonic attenuation is significantly affected by particle properties. The numerical results also show that both the particle type and particle size distribution should be carefully taken into account in the dispersions with polydisperse mixed particles, where the MCM can give a more direct description of the physics of sound propagation compared with the conventional models.

关键词： Ultrasound Ultrasonic attenuation Monte Carlo method Particle size measurement

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