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Capacitance probe for water holdup measurement in crude oil-water flows

Measurement: Sensors 2020年 10-12卷

作者： Zheng, Xuebo Yang, Bo Bai, Bofeng State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

Water holdup in crude oil-water flows is a crucial parameter to identify flow patterns or monitor the flow process in oil production. It has been increasingly important to accurately predict water holdup. Due to the simple structure and robust performance, capacitance probes have been widely used in experimental research and industrial application. In this paper, we proposed a water holdup measurement device based on a capacitance probe for crude oil-water flows. The measurement principle lies in the fact that the output capacitance is proportional to the part of the probe immersed in water. It was found that when inserted into crude oil, the surface of the probes will absorb hydrocarbons and form an oil film covering the probes. The formed oil film will reduce the sensitivity of the output capacitance to the water layer height. The thicker the film the lower the sensitivity. We examined the parameters that affect the thickness of the formed oil film and found that the thickness is mainly dependent on temperature and water holdup. The higher the temperature the thinner the formed oil film. The reason is that an increase of temperature leads to a decrease of viscosity. In addition, as the temperature approached about 50 °C, the thickness is nearly unchanged. As for the water holdup, at low temperatures the effect is considerable. At relatively high temperatures, the effect is minor and can be neglected. The experimental results showed that the capacitance probes have the highest sensitivity at about 50 °C. We designed and manufactured a prototype of the measurement device. The probes were inserted with heating wires to heat the crude oil near the probes and the current was controlled by an integrated circuit to maintain the temperature at about 50 °C. The field test showed that the natural gas entrained in the production fluids caused the device to under-predict the water holdup. After gas-liquid separation, the prediction errors were within ±6%. © 2020 The Author

关键词： Crude oil

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A New Reduced Reaction Mechanism of the Surrogate Fuel for RP-3 Kerosene

SSRN

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SSRN 2022年

作者： Liu, Jing Hu, Erjiang Zheng, Weilin Zeng, Wen Chang, Yachao State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Shangxi Xi’an710049 China Liaoning Key Lab of Advanced Test Technology for Aerospace Propulsion System Shenyang Aerospace University Liaoning Shenyang110136 China Key Laboratory of Ocean Energy Utilization and Energy Conservation Ministry of Education Dalian University of Technology Dalian116024 China

By combining the reaction class-based global sensitivity analysis (RC-GSA) methodology, species sensitivity analysis (SSA) methodology, decoupling method and genetic algorithm (GA), a reduced reaction mechanism of the surrogate fuel (10% n-dodecane/14% n-decane/30% iso-hexadecane/36% methylcyclohexane/10% toluene, in mole fraction) for RP-3 kerosene was constructed. As an example, the detailed construction process of skeleton mechanism of methylcyclohexane (MCH) was presented, and the skeleton mechanism constructions of other components in the surrogate fuel were similar to that of MCH. First, the dominant reaction classes in the fuel-relevant mechanism of MCH were recognized by the RC-GSA, the representative species in each retained reaction classes were selected by the SSA, and the skeleton fuel-relevant mechanism of MCH was developed. Second, through combining the skeleton fuel-relevant mechanism of MCH with the reduced reaction mechanism of C 0 -C 3 by the decoupling method, the initial skeleton mechanism of MCH was obtained. Third, based on the GA, the rate constants of fuel-relevant reactions in the initial skeleton mechanism of MCH were optimized to enhance the prediction performance. Finally, by coupling the skeleton reaction mechanisms of n-dodecane, n-decane, toluene, iso-hexadecane, MCH, and the reduced reaction mechanism of C 0 -C 3 , a reduced mechanism (containing 121 species and 469 reactions) of the surrogate fuel for RP-3 kerosene was formed. The predicted main species concentrations during the oxidation process in the jet-stirred reactor, the ignition delay times in the shock tube and laminar flame speeds in the constant volume bomb by this reduced mechanism are in good agreement with the corresponding experimental data of RP-3 kerosene. © 2022, The Authors. All rights reserved.

关键词： Sensitivity analysis

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Enhancing thin film boiling heat transfer through electric field and surface Macro-Structure Synergy: Insights from bubble dynamics modulation

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International Journal of Heat and Mass Transfer 2025年 249卷

作者： He, Changqiu Tian, Jiameng Chen, Yiqi Zhu, Yuchen Liu, Xin Wang, Hai Wang, Zhentao Cai, Benan Wang, Changqing Wang, Junfeng Zhou, Zhifu Chen, Bin School of Energy and Power Engineering Jiangsu University Zhenjiang212013 China School of Energy and Power Engineering Chongqing University Chongqing 400044 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China Laboratory of Thermo-fluid Science and Nuclear Engineering School of Energy and Power Engineering Northeast Electric Power University Jilin 132012 China National Key Laboratory of Marine Engine Science and Technology Shanghai 201108 China

Improving boiling heat transfer in thin liquid films by employing external electrical fields and macro-structured surfaces presents promising for tackling the growing difficulties related to high-heat-flux thermal management in electronic devices. In this study, six distinct macro-structured surfaces are designed and fabricated to gain insight into how liquid film thickness, structural parameters, and applied voltage affect the efficiency of boiling heat transfer with ethanol as the coolant. High-speed imaging and precise heat transfer measurements are employed to characterize the boiling performance, providing insights into the underlying fundamentals driving the observed enhancements. Results reveal that applying a 4-kV voltage increases departure frequency of bubble by 86 % and a 28 % reduction in diameter, causing a 20 % improvement in critical heat flux (CHF). CHF is positively correlated with liquid film thickness and pin height, but negatively with pin spacing, achieving a 139 % increase under optimal conditions. Liquid film thickness was found to have the most significant impact on CHF, followed by pin spacing and applied voltage. By simplifying the void fraction equation, a new CHF correlation is proposed that introduces a dimensionless characteristic length, representing the relative effects between bubble size and film thickness, while accounting for the synergy between the electric field and surface macro-structure. © 2025 Elsevier Ltd

关键词： Electric heating

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Influence of Different Equations of State on Simulation Results of Supercritical CO_(2) Centrifugal Compressor

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Mechanical engineering Science 2021年第2期3卷 25-33页

作者： Yueming YANG Bingkun MA Yongqing XIAO Jianhui QI Shandong Engineering Laboratory for High-efficiency Energy Conservation and Energy Storage Technology&Equipment School of Energy and Power EngineeringShandong UniversityJinanChina Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy Utilization North China Electric Power UniversityBeijingChina

Supercritical CO_(2)(SCO_(2))Brayton cycle has received more and more attention in the field of power generation due to its high cycle efficiency and compact ***_(2) compressor is the core component of the cycle,and the improvement of its performance is the key to improving the efficiency of the entire ***,the operation of the SCO_(2) compressor near the critical point has brought many design and operation *** on the Reynolds Averaged Navier-Stokes(RANS)model,the performance and flow field of SCO_(2) centrifugal compressors based on different CO_(2) working fluid models are numerically investigated in this *** stability and convergence of the compressor steady-state simulation are also *** results show that the fluid based on the Span-Wanger(SW)equation can obtain a more ideal compressor performance curve and capture a more accurate flow field structure,while the CO_(2) ideal gas is not suitable for the calculation of SCO_(2) centrifugal *** its flow field can be used as the initial flow field for numerical calculation of centrifugal compressor based on CO_(2) real gas.

关键词： Supercritical CO_(2) Centrifugal compressor Near the critical point Compressor performance Real gas equation of state

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Phosphorus Flame Retardant Modified Aramid Nanofiber Separator for Advanced Safety Lithium-Sulfur Batteries

SSRN

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SSRN 2024年

作者： Liu, Jianwei Zhu, Lei Wang, Jianan Chai, Qinqin Sun, Shiyi Chen, Xin Wang, Xue Zhang, Yating Yan, Wei College of Chemistry and Chemical Engineering Xi’an University of Science and Technology Shaanxi Xi’an710054 China Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiao tong University Shaanxi Xi’an710049 China Xianggui Manganese Industry Co. Ltd. Shaanxi Province Ziyang County725300 China School of Physics and Electrical Engineering Weinan Normal University Shaanxi Weinan714099 China Xi'an Hantang Analysis & Test Co. Ltd Xi’an710201 China

Safety concerns have perennially impeded the large-scale implementation of high-energy-density storage systems. Nevertheless, because the intrinsic drawbacks of the commercial polyolefin separator are poor thermal stability and low flammability with a large thermal contribution, the development of an advanced separator that solves the above questions is imminent. In this work, gradient flame-retardant aramid nanofiber separators (T-PMIA) were synthesized by a single-step electrospinning method. The T-PMIA separator demonstrates excellent Li-ion diffusion and proficiently suppresses the "shuttle effect" through its plentiful multilevel beaded structure and robust anchoring of soluble polysulfides (Li2Sx), achieved by optimizing the functional groups P and -P-O. Moreover, the enhanced separator exhibits a rapid self-extinguishing feature (self-extinguishing time: 0.20 s) and impressive mechanical properties (tensile strength of up to 12.58 MPa and puncture force of 0.94 N). Accordingly, the T-PMIA separator still showed a stable cycling performance (maintain 901.7 mAg-1 after 100 cycles) even at high temperature (80 ℃). This simple separator strategy offers a highly competitive option for the large-scale production of high-safety lithium-sulfur (Li-S) batteries. This uncomplicated separator strategy presents a compelling solution for the large-scale production of high-safety lithium-sulfur (Li-S) batteries © 2024, The Authors. All rights reserved.

关键词： Separators

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The formation of droplet encapsulating particles in a Y-typed microchannel

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Measurement: Sensors 2021年 14卷

作者： Wang, Qing Liu, Qi Fan, Liang-Liang Zhao, Liang School of Mechanical Engineering Xi'an Jiaotong University Xi'an China School of Food Equipment Engineering and Science Xi'an Jiaotong University Xi'an China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an China

Droplet encapsulating particles has great potentials in microfluidic measurement and detection in many fields, such as biomedicine and food science. It is of great importance to investigate the formation of droplet encapsulating particles in microchannel. In this paper, considering the influence of channel angle, particle size, and volume fraction, VOF model and DPM model are combined to systematically study the formation of droplet containing particles in a Y-typed microchannel. The simulation results show that the particle size and concentration significantly influence the formation of droplet. In addition, in comparison with the formation of simple droplet, the angle of Y-typed microchannel and particles have synergistic effect on the droplet formation. The present work is of help for the precise control on the formation of droplet encapsulating particles, which is highly required for the following measurement and detection. © 2021 The Author(s)

关键词： Microchannels

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Study on the heat and mass transfer characteristics of wet air in metal foam in the space station environment

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Applied Thermal engineering 2025年 277卷

作者： Guowei Zhu Liang Zhang Yujuan Xia Hantao Zhou School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai 200093 China Key Laboratory of Multiphase Flow and Heat Transfer in Shanghai Power Engineering University of Shanghai for Science and Technology Shanghai 200093 China China National Institute of Standardization Beijing 100191 China

This paper has developed a novel dehumidification device for space station environment, which uses foam copper as the core, with a Stirling refrigerator providing cooling, heat pipes assisting in heat conduction and a siphon water guidance system employed to remove condensate. Experiments on dehumidifying wet air within the foam copper were then carried out under simulated microgravity dehumidification conditions. The experimental conditions included different inlet air temperatures, humidities, air velocities, and cold end temperatures of the Stirling refrigerator. The experimental research indicates that as the inlet air temperature rises from 20 °C to 30 °C, the mass transfer coefficient increases by 57.06 %, and the sensible heat coefficient rises by 10.62 %. When the air velocity increases from 0.4 m·s −1 to 1.4 m·s −1 , these two coefficients increase by 111.79 % and 170.83 %, respectively. In contrast, increasing the relative humidity from 50 % to 80 % results in a 34.09 % decrease in the sensible heat coefficient, while the mass transfer coefficient increases by 11.4 %. When the cold-end temperature rises from 8 °C to 13 °C, the sensible heat transfer and mass transfer coefficients increase by 9.63 % and 4.06 %, respectively. Based on this, a sensitivity analysis was conducted using the experimental data, and heat and mass transfer correlations were fitted. The mean standard deviations of the heat and mass transfer correlations are 3.74 % and 6.30 %, respectively, indicating a high degree of fitting accuracy. This work provides a new humidity control solution for future space station thermal management systems.

关键词： Heat and mass transfer Metal foam Space station environment Wet air

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Theoretical Analysis on the Lifetime of Sessile Droplet Evaporation

Theoretical Analysis on the Lifetime of Sessile Droplet Evap...

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作者： Shen, Yang Cheng, Yongpan Xu, Jinliang Zhang, Kai Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy North China Electric Power University Beijing102206 China School of Energy Power & Mechanical Engineering North China Electric Power University Beijing102206 China

There are two stages for a sessile droplet evaporation on the solid substrate, one is the "constant contact radius" (CR) mode, the other is the "constant contact angle" (CA) mode. In this paper, the theoretical model is built up for sessile droplet evaporation for the two modes, the lifetime of evaporating droplet is obtained under different initial contact radius, initial contact angle and critical contact angle for mode transition. It is found that in the CR mode, the variation of initial contact angle is nonlinear with the time. For both CR and CA modes the lifetime is proportional to R02 (R0 is the initial contact radius of droplet) for two modes. When the critical contact angle for mode transition from CR to CA is increased, the lifetime for CR mode is decreased while the lifetime for CA mode is increased, and the overall lifetime is also increased. This result may be of great significance for sessile droplet evaporation. © Springer Nature Switzerland AG 2020.

关键词： Evaporation

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Effects of Flue Gas Recirculation on Combustion and Heat Flux Distribution in 660 Mw Double-Reheat Tower-Type Boiler

SSRN

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SSRN 2022年

作者： Deng, Lei Dong, Lingxiao Bai, Yang Wu, Yuhao Liu, Hu Belošević, Srdjan Tomanović, Ivan Che, Defu State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an710049 China Guoshen Institute of Technology CHN ENERGY Xi'An710065 China Department of Thermal Engineering and Energy "VINČA" Institute of Nuclear Sciences National Institute of thе Republic of Serbia University of Belgrade Mike Petrovića Alasa 12-14 11351 Vinča PO Box 522 Belgrade11001 Serbia

The ultra-supercritical double-reheat boiler has attracted more attention because of high parameters, low pollution and large capacity. However, there are some difficulties in the development of this technology, such as adjusting the reheat steam temperature. In this study, computational fluid dynamics simulation is used to analyze a 660 MW double-reheat tower-type pulverized coal-fired boiler. The influence of flue gas recirculation (FGR) on heat transfer characteristics and combustion process in the furnace (including heating surfaces in the upper parts of the furnace) are evaluated. The user-defined function approach predicates CO reduction effect on NO x . The results show that the flow at the horizontal section through the centerline of recirculating flus gas nozzles is rotating. The velocity distribution changes into an elliptical rotating flow when FGR ratio is 20%. At higher FGR ratios, the high-temperature area (1565-1700 K) shrinks and both the NO x concentration at the low-temperature superheater outlet and oxygen concentration in the furnace descend. Oxygen concentration at low-temperature superheater outlet first increases and then decreases. In the main combustion zone, the heat flux peak of water-cooled wall is about 330 kW m -2 . As FGR ratio increases from 0% to 20%, the rate of water-cooled wall heat absorption to total boiler decreases by 3.50%. This rate for reheater and superheater increases by 2.53% and 2.13%, respectively. © 2022, The Authors. All rights reserved.

关键词： Temperature

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Fluoride-Salt-Cooled High-Temperature Reactor: An Integrated Nuclear-Based Energy Production and Conversion System

SSRN

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SSRN 2023年

作者： Zhang, Dalin Li, Xinyu Jiang, Dianqiang Zhou, Xingguang Lv, Xindi Yun, Shichang Wu, Wenqiang He, Xuanang Li, Haoyang Min, Xin Chen, Kailong Tian, Wenxi Qiu, Suizheng Su, G.H. Zhao, Quanbin Fu, Yao Tang, Chuntao Zhuo, Wenbin Li, Jinggang Zuo, Jiaxu 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 Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai201800 China Shanghai Nuclear Engineering Research & Design Institute CO. LTD. Shanghai200233 China CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology Nuclear Power Institute of China Chengdu610213 China China Nuclear Power Technology Research Institute Guangdong Shenzhen518000 China Nuclear and Radiation Safety Center Ministry of Ecology and Environment People's Republic of China Beijing100082 China

Based on the analysis of energy structure and the development trends of advanced nuclear energy technology, combining the complementary advantages of nuclear energy and other energy sources in China, the Fluoride-salt-cooled High-temperature Reactor(FuSTAR) system has been proposed. FuSTAR system is designed to address production capacity issues in areas with energy shortages or resource concentration and can be combined with high-temperature process heat to achieve high-value-added processes such as hydrogen production. In this paper, the Tri-structural isotropic fuel combined with helical cruciform elements has been studied in detail on the neutron physics and thermal-hydraulic properties, and the flow and heat transfer experiment is carried out for the first time. The multilayer nonlinear programming method has been applied to the design of thermal transport systems. Then the optimal parameters and configuration of the thermoelectric conversion system are obtained by the superstructure optimization method. The inherent safety of FuSTAR is demonstrated through deterministic safety analysis. In addition, the iodine-sulfur cycle technology and the characteristics of tritium production are also analyzed. This study highlights the significant potential of integrating nuclear energy with other energy sources in an optimized energy-production system. © 2023, The Authors. All rights reserved.

关键词： Nonlinear programming

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