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SSRN 2022年

作者： Sun, Tianli Wu, Ye Mei, Jian Han, Yinghui Cai, Tianyi Liu, Dong MIIT Key Laboratory of Thermal Control of Electronic Equipment School of Energy and Power Engineering Nanjing University of Science and Technology Nanjing210094 China Advanced Combustion Laboratory School of Energy and Power Engineering Nanjing University of Science and Technology Nanjing210094 China College of Resources and Environment University of Chinese Academy of Sciences Beijing100049 China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai200093 China

Improving combustion efficiency of diesel engine is very important in the current background of carbon neutralization because sufficient combustion means low pollutant emission and little energy waste. In past studies, catalytic coatings were used in diesel engine to speed up fuel-burning rates and reduce emissions caused by insufficient combustion. Insufficient combustion mainly in high temperature and low oxygen area, using oxygen carrier as the coating material for the combustor surface to support additional –O and regulate the combustion process also is a promising strategy. A desired Fe-based oxygen carrier with excellent redox capability and stability was fabricated to convert fuel pyrolysis products into CO2, H2O and extra heat to improve the fuel combustion efficiency. A range of cerium modified Fe2O3 oxygen carriers were prepared and tested with ethylene as a representative fuel to investigate the redox capability and stability during fuel pyrolysis process. In addition, the gas-solid surface reaction of ethylene and iron oxide was studied by density functional theory (DFT) to illustrate their good reactivity and the mechanism of doping optimization. It was found that when using the FeCe-2 oxygen carrier with the mole ration of Fe and Ce is 9:1 during ethylene pyrolysis process, the ethylene was oxidized most sufficiently (CO2 yield>92%). DFT simulation showed that Ce doping improved the reactivity of surface oxygen. Experimental data and characterization analysis showed that the addition of Ce improved oxygen vacancy capacity to enhance the oxidation for the pyrolysis products. Due to the role of both, the ethylene and its pyrolysis products were converted into CO2 and H2O quickly and effectively. The obtained results indicate that FeCe-2 is the potential oxygen carrier coating material for combustion efficiency improvement. © 2022, The Authors. All rights reserved.

关键词： Carbon dioxide

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A Dynamic Plunger Lift Model for Shale Gas Wells

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Fluid Dynamics & Materials Processing 2023年第7期19卷 1735-1751页

作者： Shiyu Miao Xiao Liu Xiaoya Feng Haowen Shi Wei Luo Peng Liu Petroleum Engineering Institute of Yangtze University Wuhan430100China Laboratory of Multiphase Pipe Flow Gas Lift Innovation CenterChina National Petroleum Corp.Yangtze UniversityWuhan430100China Key Laboratory of Drilling and Production Engineering for Oil and Gas Wuhan430100China Sichuan Shale Gas Exploration and Development Limited Liability Company Chengdu640000China Sichuan Changning Gas Development Company PetroChina Southwest Oil&Gas Field CompanyChengdu610051China Oil and Gas Technology Research Institute of Changqing Oilfield Company PetroChinaXi’an710018China

At present,the optimization of the plunger mechanism is shale gas wells is mostly based on empirical methods,which lack a relevant rationale and often are not able to deal with the quick variations experienced by the production parameters of shale gas wells in comparison to conventional gas *** order to mitigate this issue,in the present work,a model is proposed to loosely couple the dynamics of gas inflow into shale gas wells with the dynamics of the liquid *** from the flow law that accounts for the four stages of movement of the plunger,a dynamic model of the plunger lift based on the real wellbore trajectory is *** model is then tested against 5 example wells,and it is shown that the accuracy level is higher than 90%.The well‘switch’,optimized on the basis of simulations based on such a model,is tested through on-site *** is shown that,compared with the original switch configuration,the average production of the sample well can be increased by about 15%.

关键词： Shale gas well complex and more complex well bore structure plunger lift loose coupling simulation model

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Experimental Study of Pool Boiling Heat Transfer on Hydrophilic and Hydrophobic Surface Coupled Micro-Pin-Finned

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SSRN 2023年

作者： Song, Gege Ma, Xiang Xu, Pengzhuo Zhang, Yonghai Weia, Jinjia School of Chemical Engineering and Technology Xi’an Jiaotong University Shaanxi Xi’an710049 China Xi’an Navigation Technology Research Institute Shannxi Xi’an710068 China Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

The pool boiling heat transfer properties of uniform micro-pin-finned surface, hydrophilic and hydrophobic surface were evaluated by employing FC-72 as the working medium. Three hydrophilic and hydrophobic coupled rectangular copper column surfaces (HH4, HH9, and HH16) were invented in order to investigate their boiling heat transfer characteristics further. The effect of several subcoolings (0K, 15K, and 25K) on the critical heat flux was explored by connecting the micro-pin-finned surface (PF) and the smooth surface (SS). A high-speed camera was set up to study the bubbles' behaviors. The results reveal that the hydrophilic and hydrophobic coupled micro-pin-finned copper surface can achieve a higher critical heat flux (CHF) than the rectangular micro-pin-finned surface, but heat transfer performance (HTC) drops slightly (both saturated boiling and subcooling boiling). Visual monitoring demonstrates that the hydrophilic and hydrophobic coupled rectangular micro-pin-finned copper surface may successfully avoid bubble coalescence, especially during subcooled boiling. Furthermore, the hydrophilic and hydrophobic coupled rectangular micro-pin-finned copper column surface described in this paper might serve as an ideal replenishment route to avoid drying and delay the emergence of a boiling crisis. The factors responsible for the impact of the Lattice width coefficient and the Vapor column spacing coefficient on CHF were analyzed. Fluid replenishment and bubble formation behavior were applied to clarify the strengthened heat transfer and triggering mechanism of CHF on the surface of the hydrophilic and hydrophobic coupled rectangular micro-pin-finned copper column surface. © 2023, The Authors. All rights reserved.

关键词： Heat flux

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Publisher's Note: Numerical investigation of the yawed wake and its effects on the downstream wind turbine [J. Renewable Sustainable Energy 8, 033303 (2016)]

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Journal of Renewable and Sustainable Energy 2016年第5期8卷

作者： Miao, Weipao Li, Chun Yang, Jun Xie, Xiaoyun School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai200093 China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering Shanghai200093 China Laboratory of Fluid and Power Machinery Xihua University Jinniu District Sichuan610000 China Shanghai Behr Thermal Systems Co. Pudong District Shanghai201206 China

This article was originally published online on 9 June 2016 with affiliation 3 incorrectly assigned to the second author. Chun Li is not affiliated with the Lab

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Microstructure evolution and properties evaluation of a novel bondline based on Cu@Sn Preform during temperature treatment

Microstructure evolution and properties evaluation of a nove...

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第十九届国际电子封装技术会议(ICEPT 2018)

作者： Hongyan xu Ju Xu Puqi Ning Jianqiang Li Beijing Engineering Laboratory of Electrical Drive System & Power Electronic Device Packaging Techno State Key Laboratory of Multiphase Complex System Institute of Process EngineeringChinese Academy o

The microstructure and properties of Cu@Cu3Sn@Cu6Sn5three-dimensional network bonding interconnections based on Cu@Sn preform was *** through holes were observed at the bulk in as-reflowed,aged and temperature cycling *** evolution and phase transformation during thermal treatment test were studied,the shear strength of three-dimensional network bondlines for as-reflowed and thermal treating samples were compared and *** phase composition of as-reflowed interconnects was Cu/Cu6Sn5 and transformed to Cu/Cu3Sn/Cu6Sn5 after thermal *** failure modes of as-reflowed,aged and temperature cycling test were found in three-dimensional network structure *** average shear strength of the as-reflowed and the thermal treatment bonding interconnections are 49.5 Mpa and 24.9 Mpa,respectively,and crack initiated and propagated that perpendicular to substrate during the aging *** fracture surfaces of the temperature treatment bonding interconnections after shearing test were characterized in *** results show that the Cu3Sn phases in Cu@Cu3Sn@Cu6Sn5 three-dimensional network structure affected its strength and fracture *** Cu-rich substrate side at the fracture surfaces is always regular while the bulk phases are often accompanied by shear bands and dimples.

关键词： microstructure evolution as-reflowed aging test temperature cycling shearing strength

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The Influence of Tube Diameter Parameters on the flow Resistance and Heat Transfer Characteristics of Supercritical Co2 in Horizontal Tubes

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SSRN 2023年

作者： Cheng, Liangyuan Xu, Jingliang Wang, Qingyang Dong, Xinyu Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy Utilization North China Electric Power University Beijing102206 China Key Laboratory of Power Station Energy Transfer Conversion and System of Ministry of Education China Hebei Key Laboratory of Low Carbon and High Efficiency Power Generation Technology North China Electric Power University Baoding071003 China

The diameter parameters of tubes can affect flow and heat transfer characteristics of supercritical fluids, which is crucial for improving the efficiency and safe operation of thermal power generation systems. Based on the above, experimental research was conducted to investigate the influence of tube diameter parameters on the flow resistance and heat transfer of supercritical carbon dioxide(sCO2) in horizontal tubes. Stainless steel smooth circular tubes with diameters of 8 mm, 10 mm, and 12 mm were used as the test section, and various experiments were carried out under the range of mass flux: 509.23-1267.34 kg/m2s, heat flux: 97.91-410.43 kW/m2, and operating pressure: 5.542-15.427 MPa. The results reveal that the tube diameter parameters have a greater influence on the heat transfer in the two-phase-like regime, while a relatively small influence on the heat transfer in the liquid-like and vapor-like regimes;Furthermore, it is found that the influence of tube diameter on heat transfer is more significant at the top generatrix through the analysis of local heat transfer. In addition, the sudden change of frictional pressure drop (DPf) near the pseudo-critical point is also related to the tube diameter parameters, and the tube diameter influence is almost negligible when the pressure exceeded 1.5Pc. Based on the pseudo-boiling theory, the tube diameter parameters influence the flow stratification of sCO2 in horizontal tubes, and correlations of the maximum wall temperature difference between the top and bottom generatrix (DTmax) for different diameter tubes between the supercritical boiling number (SBO) and the supercritical Reynolds number of LL phase (ReLL) was established. Our work can provide a new research direction for flow and heat transfer characteristics of supercritical fluid in horizontal tubes, and theoretical guidance for the design of heat exchange tubes in engineering. © 2023, The Authors. All rights reserved.

关键词： Heat transfer

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Effects of Hydrothermal and Hydrothermal Oxidation Pretreatments on Physicochemical Properties of High Value-Added Biochar Fuel Pellets and Activated Carbon Materials

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SSRN 2023年

作者： Lang, Sen Zhang, Shouyu Yang, Jifan Zhou, Yi Liu, Simeng Xu, Zihang Han, Xiuyuan Huang, Jiantian School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai200093 China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering Shanghai200093 China Huazhan Aerospace Electric Appliance Co. LTD Aerospace Science and Industry Corporation Suzhou215129 China

In this paper, cotton stalk (CS) and Chinese fir sawdust (FS) were treated for hydrothermal pretreatment with or without H2O2, and then respectively pyrolyzed and activated to prepare biochar pellets and activated carbon materials. The results show that compared with hydrothermal pretreatment (HT), hydrothermal oxidation (HTO) pretreatment has stronger degradation ability of hemicellulose and cellulose. With the increase of pretreatment temperature, some decomposed substances repolymerize to form lignin-like substances. In the 160-260oC temperature range, the physical properties of biochar pellets prepared under HT 230oC and HTO 200oC are the best, and crystalline cellulose plays a key role in it. The calorific value and energy density of the biochar pellets obtained after pretreatment were consistent with the variation trend of their physical properties. The combustion characteristics of treated CS/FS biochar pellets gradually decreased with the increase of temperature. Compared with CS, FS biochar have better energy density and physical properties due to high cellulose content. The CS-HTO200-A has the highest specific surface area and pore volume, which is 118.1% and 111.7% higher than that of raw materials, and mainly consists of micropores. Cellulose is beneficial to increase the specific surface area of activated carbon, while lignin has the opposite effect. © 2023, The Authors. All rights reserved.

关键词： Physicochemical properties

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Evaluation of a Numerical Model for Predicting flow and Heat Transfer in a Hexagonal Helical Cruciform Seven-Rods Bundle and Analysis of Rod Bundle Size Independence

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SSRN 2024年

作者： Jiang, Dianqiang Deng, Jian Zhang, Dalin Zhou, Xingguang Xiao, Changzhi Tian, Wenxi Qiu, Suizheng Su, Guanghui H. State Key Laboratory of Multiphase Flow in Power Engineering Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology School of Nuclear Science and Technology Xi’an Jiaotong University Xi’an710049 China Nuclear Power Institute of China Science and Technology on Reactor System Design Technology Laboratory Chengdu610213 China China Institute of Atomic Energy Beijing611731 China

In this study, the accuracy and applicability of the numerical model are comprehensively evaluated based on the experimental data of a hexagonal helical cruciform (HC) seven-rods bundle. The STAR CCM+ is utilized as a tool to obtain predicted results of flow and heat transfer in different flow regions. The numerical results indicate that it is an improved method to set a negative heat flux on the hexagonal wall in the laminar flow region. The Reynolds stress transport model can accurately predict the experimental results of heat transfer in the transitional flow region, with an average wall temperature deviation of 2.8℃. The SST k-ω model with cubic constitutive option can accurately predict the experimental results of the flow resistance, and a relative error of f is 1.8%. In the turbulent flow region, the SST k-ω model with cubic constitutive option provides an accurate prediction, with an average wall temperature deviation of 3.7℃. The realizable k-Ε two-layer model can accurately predict the flow resistance, and the relative error of f is 0.1%. The preferred numerical model is used to analyze the size independence of the HC rod bundle. This work provides certain guidelines for the accurate simulation in the HC seven-rods bundle. © 2024, The Authors. All rights reserved.

关键词： Computational fluid dynamics

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Numerical Study on Benchmark Analysis of NACIE-UP Facility with Uniform and Non-Uniform power Distribution

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SSRN 2024年

作者： Li, Haoyang Zhang, Dalin Zhou, Lei Deng, Jian Tian, Wenxi Su, Guanghui Qiu, Suizheng State Key Laboratory of Multiphase Flow in Power Engineering Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology School of Nuclear Science and Technology Xi’an Jiaotong University Xi’an710049 China Nuclear Power Institute of China 328 Changshun Avenue Chengdu610213 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

The NACIE-UP facility is located at the ENEA Brasimone Research Centre and is designed to investigate the thermo-hydraulic properties of LBE within a wire-spaced assembly under uniform and non-uniform power distribution conditions. In this study, the thermo-hydraulic characteristics of FPS are analyzed. ANSYS Fluent solver is applied with the COUPLE algorithm of RANS [[EQUATION]] model. Cheng&Tak correlation and computational conditions are implanted into Fluent in the form of UDFs. The results show that the RMSEs of ADP10SS1 and ADP10SS2 are 2.52 K and 3.69 K, 7.05 K and 8.48 K for ADP06SS1 and ADP06SS2, respectively, which indicate that the adopted models have good prediction ability for the temperature of the experimental conditions. Meanwhile, the heat transfer characteristics are investigated and compared with the correlations of Ushakov, Mikityuk, Kazimi and Carelli. Above all, this study provides quantitative and qualitative analysis for verification and validation of CFD/STH code and stand-alone CFD simulation. © 2024, The Authors. All rights reserved.

关键词： Heat transfer

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Connectivity control of effective sorption capacity and kinetics in heterogeneous porous media

Connectivity control of effective sorption capacity and kine...

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第一届全国水处理与回用学术会议

作者： Li Wang Hang Wen Li Li Department of Environmental Science and Engineering State Key Laboratory of Multiphase Flow in Power Department of Energy and Mineral Engineering Penn State UniversityUniversity ParkPA 16802USA Department of Civil and Environmental Engineering Penn State UniversityUniversity ParkPA 16802USA

This work examines the effects of spatial heterogeneity in regulating Cr(Ⅵ)sorption under different geostatistical characteristics and spatial scale *** flow-through experiments in heterogeneous columns of 0.1 meters have shown that sorption in heterogeneous media can be characterized by three effective quantities: sorption capacity(Csc,m),early-stage fast sorption rate(kc1),and late-stage slow sorption rate(kc2).Two-dimensional reactive transport models are developed by calibrating these data from these columns of different illite distribution patterns and permeability contrasts between illite and quartz *** models were further run in geostatistical fields of different permeability variance(σ2lnκ,0.2 and 4.5)and length scale(0.1 to 1.0 m)conditions to quantify their role in determining effective sorption capacity and *** results indicate that in highly-connected columns with high permeability variance and long s,Cr(Ⅵ)-containing flow travels mostly through the high permeability,non-sorbing quartz *** therefore occurs mostly at the illite-quartz *** capacity and early fast rates(kc1)therefore depend strongly on the connectivity and properties that control advective transport of the *** longer time scales,diffusive transport determines the late-stage slow rates(kc2)and the breakthrough tailing,which depend less on connectivity and more on the size of the low-permeability illite zones and transverse dispersivity α*** to homogeneous columns of the same illite content,highly-connected patterns can reduce effective sorption capacity by up to a factor of 6.7,fast sorption rates by a factor of 25.0,and slow sorption rate by a factor of more than 2.0 orders of *** the domain length increases,the effects of spatial heterogeneities on sorption capacity and early stage fast sorption rates diminish due to longer length scales for mixing;these effects however persist for the late-stage slow sorp

关键词： connectivity sorption capacity spatial heterogeneity length scales reactive transport modeling

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