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SSRN 2025年

作者： Liu, Hang Li, Yang Huang, Heng Zhou, Zhifu Wu, Wei-Tao Wei, Lei Lyu, Jizu Hu, Chengzhi Li, Yubai Song, Yongchen Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education Dalian University of Technology Dalian116024 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi’an710049 China School of Mechanical Engineering Nanjing University of Science and Technology Nanjing210094 China Department of Mechanical and Energy Engineering Southern University of Science and Technology Shenzhen518055 China School of Mechanical Engineering Guangdong Ocean University Zhanjiang524088 China

The gas diffusion layer (GDL) of proton exchange membrane fuel cells (PEMFCs) is a critical component for the transport of reactants. The efficiency of reactant gas transport remains a major technical challenge in the field today. The anisotropic structure of the GDL gives rise to substantial variations of gas diffusion as well as permeability in different directions. The study employs X-CT technology to obtain the actual GDL’s geometry, aiming to investigate a spatial structure at the microscale and its gas transport characteristics. CFD method is used to simulate and study the gas diffusivity and gas permeability of GDL with four different thicknesses. The numerical simulation results show the diffusivity and permeability in the Through-plane (TP) direction are lower than those in the In-plane (IP) direction. Moreover, the effective diffusion coefficient decreases with increasing thickness, but is also dependent on the solid fibre structure of GDL. Horizontal alignment of the carbon fibers and the disc-shaped adhesive contributes to the anisotropy between the TP and IP directions, resulting in anisotropic gas transport. The purpose of the study is to supply critical references for manufacturing techniques and optimization of gas transport in GDLs. © 2025, The Authors. All rights reserved.

关键词： Gas permeability

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Corrigendum to “Experimental study on flow boiling and circumferential non-uniform heat transfer characteristics in helically-coiled tube under coupled heat transfer conditions” [Appl. Therm. Eng. 258(Part C) (2025) 124844]

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Applied Thermal engineering 2025年 261卷

作者： Hengyuan Wang Qiyu Xuan Hailin Lei Xi Li Zhibin Li Huixiong Li State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an 710049 China

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Study on thermo-fluid-chemical coupling simulation and characteristic fields evolution during in-situ pyrolysis of tar-rich coal

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International Journal of Heat and Fluid flow 2025年 116卷

作者： Meijing Chen Yongbo Du Chang’an Wang Yujie Hou Tianlin Yuan Liujun Chang Lei Deng Defu Che State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an 710049 China

Underground in-situ pyrolysis of tar-rich coal is an effective approach to expand the supply channels of oil and gas while ensuring energy security, and it has currently aroused wide attention in the academic community. The coupling of multiple interdependent physical fields causes the in-situ pyrolysis process and related phenomena. However, existing studies usually only have focused on a single process. The study proposed a three-dimensional (3D) model for the in-situ pyrolysis of tar-rich coal employing external high-temperature fluids. Numerical simulation was used to achieve the transient calculation of the coupling model of chemical reaction, fluid flow, and heat transfer. The impacts of medium type, medium temperature, inlet rate, well patterns, and the number of horizontal fractures were investigated by characterizing the temperature and concentration fields. The results indicate that, under the basic working condition, the pyrolysis reaction of tar-rich coal in the formation has been completed after ∼28.5 months of heat injection. Both N 2 and CO 2 are heat carriers with greater advantages in heat transfer as compared to H 2 O (g). The threshold of injection rate is 5 m·s −1 . The heat transfer effect of coal seams with 4 injection wells is obviously better than that of 1 and 2 injection wells. The number of 3 horizontal fractures is superior to 1 and 2 fractures, which can effectively enhance heat transfer and promote the thermal decomposition. The present study has emphatically investigated the evolution of characteristic fields of tar-rich coal seams under thermo-fluid-chemical coupling conditions during the in-situ pyrolysis process, providing substantial reference significance to guide the in-situ conversion mining.

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ȮH insights into the interaction of hydrogen-rich methane and water: Laser absorption experiments and chemical kinetics

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Combustion and Flame 2025年 278卷

作者： Xin Zhang Zilong Feng Congjie Hong Wuchuan Sun Zuohua Huang Yingjia Zhang State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an 710049 PR China

Flue gas recirculation and steam injection are employed in hydrogen-rich gas turbines to stabilize fuel reactivity and improve cycle efficiency, introducing high water vapor content into the combustion chamber and thereby necessitating an investigation of water-fuel interactions at elevated temperatures. This study employed UV laser absorption diagnostics behind reflected shock waves to conduct in situ measurements of the ȮH concentration time-histories during the oxidation of CH 4 /H 2 /H 2 O/O 2 /Ar mixtures at pressures of approximately 1.3, 5.0, and 15.2 atm and temperatures ranging from 1225 to 1888 K with varying hydrogen blending and water addition ratios. The absorption lineshapes of the ȮH R 1 (5) transition in the A-X(0,0) vibronic band were characterized after broadening and shifting in Ar at different pressures, with diagnostic center wavelengths set at 306.6868 nm (1.3 atm), 306.6874 nm (5.0 atm), and 306.6886 nm (15.2 atm), respectively. The obtained ȮH concentration time-history data were compared in detail with predictions from eight representative reaction kinetic models, and the predictive capability of the models for ȮH behavior was quantitatively assessed using the error function method. NUIGMech1.1 exhibited superior performance in predicting ȮH behavior and was subsequently selected for kinetic analysis to elucidate stage-specific micro-mechanisms and identify key reactions driving the concentration evolution. The activating effect of H 2 on ȮH behavior during CH 4 oxidation was investigated. Results indicate that higher hydrogen levels intensify hydrogen-related reaction pathways, expanding the radical pools (H, ȮH, and Ö), thereby promoting fuel consumption through Ḣ-atom abstraction reactions. Additionally, by introducing weak collision H 2 O* and inert H 2 O**, the thermodynamic and kinetic effects of water were distinguished. The results show that under the current conditions, H 2 O primarily affects ȮH behavior through direct participatio

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Comparison of CO_(2)with H_(2)O as the transport medium in a biomass supercritical water gasification system

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Frontiers of Chemical Science and engineering 2024年第11期18卷 121-133页

作者： Weizuo Wang Bingru Lu Jinwen Shi Qiuyang Zhao Hui Jin State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049China

Supercritical water gasification is a clean technology for biomass conversion and *** supercritical water gasification systems,H_(2)O is often used as the transport *** in the reaction temperature at the gasification area and in the heating rate of biomass may limit the gasification rate and *** this paper,CO_(2)is used as the transport medium due to its relatively low critical point and specific heat ***,a corn stalk gasification system with different transport media is established in this paper,and the influences of various operating parameters,such as temperature,pressure and feedstock concentration,are *** results show that the gas yield in the CO_(2)-transport system decreases by no more than 5 wt%.In addition,thermodynamic analysis reveals that a system with CO_(2)as transport medium consumes approximately 25%less electricity than a system with H_(2)O as the transport *** addition,the reaction heat absorption *** results show the superiority of CO_(2)to H_(2)O as a transport medium.

关键词： biomass supercritical water gasification hydrogen production CO_(2)transport energy and exergy analyses

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Thermal-Hydraulic Calculation and Analysis on Evaporator System of a 1000 MW Ultra-Supercritical Pulverized Combustion Boiler with Double Reheat

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Journal of Thermal Science 2021年第3期30卷 807-816页

作者： WAN Li YANG Dong ZHOU Xihong DONG Le LI Juan State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049China

A double reheat ultra-supercritical boiler is an important development direction for high-parameter and large-capacity coal-fired power plants due to its high thermal efficiency and environmental *** has developed a 1000 MW double reheat ultra-supercritical boiler with steam parameters of 35 MPa at 605℃/613℃/613℃.Reasonable water wall design is one of the keys to safe and reliable operation of the *** order to examine the thermal-hydraulic characteristics of the double reheat ultra-supercritical boiler,the water wall system was equivalent to a flow network comprising series-parallel circuits,linking circuits and pressure nodes,and a calculation model was built on account of the conservation equations of energy,momentum and *** the iterative solving of nonlinear equations,the prediction parameters of the water wall at boiler maximum continue rate(BMCR),75%turbine heat-acceptance rate(THA)and 30%THA loads,including total pressure drops,flow distribution,outlet steam temperatures,fluid and metal temperatures were *** results of calculation exhibit excellent thermal-hydraulic characteristics and substantiate the feasibility of the water wall design of the double reheat ultra-supercritical boiler.

关键词： double reheat ultra-supercritical boiler water wall flow network method thermal-hydraulic characteristic

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Effects of physical properties of supercritical water on heat transfer characteristics of single particle within a particle cluster Author links open overlay panel

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Particuology 2024年第8期91卷 291-302页

作者： Xiaoyu Li Bowei Zhang Huibo Wang Hui Jin State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an710049China

The complex physical properties of supercritical water(SCW)make the heat transfer characteristics of particles within a particle cluster *** heat transfer characteristics of single particle within a particle cluster in SCW,influenced by surrounding particles,have not been effectively *** numerical simulations were conducted to investigate the heat transfer characteristics of particle clusters in SCW under different *** results were compared and analyzed with those from constant property *** was found that Reynolds number(Re)and the void fraction of particle cluster have no special effects on the variation trends of Nusselt number(Nu)for the focused ***,the particle temperature had a significant effect on the variation trends of *** effect of Re on the heat transfer rate exponent(η)of the focused particle can be divided into two zones:a significant effect zone and a non-significant effect *** effect of void fraction onηin the non-significant effect zone was *** the non-significant effect zone,ηdecreased with the increasing particle *** the significant effect zone,the variation trends ofηbecame more *** fundamental reason for this series of phenomena is the changes in distribution of physical properties.A model forηwas developed for the non-significant effect *** model can filter out the effects of Re and certain particle cluster spatial configurations,and it demonstrates good predictive performance.

关键词： Supercritical water Particle cluster Heat transfer characteristics Heat transfer rate exponent Physical properties correction

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Numerical investigation on the drag characteristics of supercritical water flow past a sphere

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Science China(Technological Sciences) 2020年第8期63卷 1509-1519页

作者： WU ZhenQun OU GuoBiao REN YiFei JIN Hui State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi'an 710049China

Numerical simulation has become a useful approach to explore the complex physical and chemical process inside the supercritical water(SCW)fluidized bed *** to the drastic and non-linear variation of water properties near pseudocritical point,the flow field and drag coefficient of SCW flow past a cold particle are considerably different from that of conventional ***,in this work,particle-resolved numerical investigation is conducted to study the flow field and drag characteristics under the influence of the special water properties *** varying the enthalpy corresponding to the particle surface temperature,which will be called the particle surface enthalpy for short,in a wide range,it realizes the study under different properties variation *** simulated results demonstrate that the variations of drag coefficient versus Reynolds number(Re)and particle surface enthalpy are in good regularity when taking the freestream temperature as reference *** drag coefficient is enhanced greatly at high enthalpy difference between particle surface and inflow,and the enhancement is mainly contributed by that of the frictional drag ***,the drag coefficient variations under different pressures are in good agreement when cases are set with the same inflow and particle surface enthalpies,*** fitting the simulated results,a new drag coefficient correlation is developed for Re range of 10–200 with consideration of the influence of the special properties *** fitting quality is good that the maximum deviation between the new correlation and simulated data is 13.92%,and the mean deviation is 3.67%.

关键词： supercritical water numerical simulation sphere drag coefficient

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Effect of 2,5-dimethylfuran addition on ignition delay times of n-heptane at high temperatures

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Frontiers in Energy 2019年第3期13卷 464-473页

作者： Zhenhua GAO Erjiang HU Zhaohua XU Geyuan YIN Zuohua HUANG State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049China

The shock tube autoignition of 2,5-dimethylfuran (DMF)/n-heptane blends (DMF)/n-100%, by mole fraction) with equivalence ratios of 0.5, 1.0, and 2.0 over the temperature range of 1200-1800 K and pressures of 2.0 atm and 10.0 atm were investigated. A detailed blend chemical kinetic model resulting from the merging of validated kinetic models for the components of the fuel blends was developed. The experimental observations indicate that the ignition delay times nonlinearly increase with an increase in the DMF addition level. Chemical kinetic analysis including radical pool analysis and flux analysis were conducted to explain the DMF addition effects. The kinetic analysis shows that at lower DMF blending levels, the two fuels have negligible impacts on the consumption pathways of each *** the DMF addition increases to relatively higher levels, the consumption path of n-heptane is significantly changed due to the competition of small radicals, which primarily leads to the nonlinear increase in the ignition delay times of DMF/n-heptane blends.

关键词： ignition delay time shock tube kinetic model 2,5-dimethylfuran (DMF) n-heptane

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The Measurement of Oil,Gas and Water flowrates in Three-Phase Slug flow

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Chinese Journal of Chemical engineering 1998年第4期6卷 37-43页

作者：蔡继勇陈听宽罗毓珊 State Key Laboratory of Multiphase Flow in Power Engineering Xi'An Jiaotong University Xi'an 710049 China

Three-sphase flow invo1ving oil-water two immiscible liquids and gas which is often foundin the fields of petroleum production has been studied in this paper.A new method with thecombination of a horizontal tube,a downward flow vertica1 tube and an orifice to measure theflowrates is *** this method the frictional pressure drop in the downward vertical tube isreplaced by that in the horizontal tube,the void fraction is derived from the gravitational pressuredrop,then the volume fraction of the individual phase can also be *** individual flowratescan be calculated when the water fraction is *** method is applicable for many kinds ofoil-wells to measure the flowrates of crude oil,natural gas and *** with other methods,the presented method involves fewer measuring *** experimental results proved quitegood accuracy of the method,with measurement deviation within 10%,and reliable results wereobtained under high Dressure conditions.

关键词： measurement flowrate three-phase flow slug flow

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