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Electromagnetic-conductance measurement method for the flow rate and void fraction of gas-liquid two-phase flows

Measurement: Sensors 2020年 10-12卷

作者： Chang, Fucheng Hu, Zitu Li, Xi Feng, Zongrui Ni, Shiyao Li, Huixiong State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University Xi'an710049 China

Gas-liquid two-phase flow systems are widely existed in many engineering systems and industrial processes, and measurement techniques for two-phase flows are crucial in a diverse range of engineering applications. Most of the existing measurement techniques usually brought extra resistance to the flow in the branch pipes and, to some extent, influenced the original distribution of the gas-liquid two-phase flows in the parallel T-junction system. In order to study the distribution characteristics of two-phase flow in vertically parallel T-junctions, the electromagnetic-conductance measurement method was developed to measure the void fraction and liquid flow rate of the gas-liquid two-phase flow in the branch pipes. Electromagnetic-conductance measurement technique has the advantages of high response rate, satisfactory accuracy and low disturbance on the flow field of gas-liquid two-phase flows. In order to calibrate the conductance measurement method, experiments were carried out with the liquid velocity range of 0.2–2 m·s-1, the gas velocity range of 0–50 m·s-1 and the volume void fraction range of 0–0.99. Through the calibration experiments, the relationship between the resistance value of each conductivity sensor and the volume void fraction of two-phase fluid was decided to be established as a logistic function. By the error analysis of the calibration results, 75.9% of experimental results of the void fraction in the gas-liquid two-phase flow fell within the ±20% error bands. The electromagnetic-conductance measurement method proposed in this paper could provide a reference for accurate and non-interference measurement of two-phase flow in parallel T-junctions. © 2020 The Authors

关键词： Two phase flow

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Polarity switching from p- to n-type in a single thermoelectric donor-acceptor copolymer by p-type doping

Research Square

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Research Square 2021年

作者： Wang, Jing Wang, Yizhuo Li, Qing Li, Zhanchao Xu, Liqing Li, Kuncai Wang, Hong Frontier Institute of Science and Technology Xi’an Jiaotong University Xi’an710054 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710054 China

The transport mechanism of organic materials is still far away from being well understood and controlled although conducting polymers have been discovered since 1977. It is rare to see conducting polyers possessing high bipolar (p- and n-type) electrical conductivities within a single bulk doped organic polymer without the assistant of gate voltage. Here, we report a novel approach to provide high performance n-type materials by p-type doping. More importantly, the bipolar electrical conductivities of the donor-acceptor conducting polymer are high, resulting high bipolar power factors among the solution-processable ambipolar D-A copolymers. A fully organic p-n junction is created in a planar film, exhibiting a high rectification ratio of 2 x 102 at ±5 V with a high current density of 3 A/cm2. Structural and spectroscopic tests have been performed to provide a fundamental understanding of the polarity switching mechanism. The results open the opportunity of making p- and n-type modules with a single conducting polymer for future modern organic electronics. © 2021, CC BY.

关键词： Conducting polymers

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Comparison of Chemical Composition and Acidity of Size-Resolved Inorganic Aerosols at the Top and Foot of Mt. Hua, Northwest China: The Role of the Gas-Particle Distribution of Ammonia

SSRN

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SSRN 2023年

作者： Li, Jianjun Feng, Qiao Liu, Haijiao Dai, Wenting Cao, Yue Shen, Minxia Liu, Yali Qi, Weining Chen, Yukun Guo, Xiao Zhang, Yifan Li, Lu Zhou, Bianhong State Key Laboratory of Loess and Quaternary Geology Key Lab of Aerosol Chemistry and Physics Institute of Earth Environment Chinese Academy of Sciences Xi’an710061 China College of Geography and Environment Baoji University of Arts and Sciences Shaanxi Key Laboratory of Disaster Monitoring and Mechanism Simulation Baoji721013 China Xi’an Institute for Innovative Earth Environment Research Xi’an710061 China National Observation and Research Station of Regional Ecological Environment Change and Comprehensive Management in the Guanzhong Plain Shaanxi China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

Aerosol pH is not only a diagnostic indicator of secondary aerosol formation, but also a key factor in the specific chemical reaction routes that produce sulfates and nitrates. To understand the characteristics of aerosol acidity in the Mt. Hua, the chemical fractions of water-soluble inorganic ions in the atmospheric PM2.5 and size-resolved particle at the top and foot of Mt. Hua in summer 2020 were studied. The results showed the mass concentrations of PM2.5 and water-soluble ions at the foot were 2.0-2.6 times higher than those at the top. The secondary inorganic ions, i.e. SO42-, NO3-, and NH4+ (SNA) were 56%-61% higher by day than by night. SO42- was mainly distributed in the fine particles (Dp 2.1 µm) was mainly attributed to the gaseous HNO3 volatilized from fine particles reacting with cations in coarse particles to form non-volatile salts (such as Ca(NO3)2). The pH values of PM2.5 were 2.7 ± 1.3 and 3.3 ± 0.42 at the top and foot, respectively. NH4+/NH3(g) plays a decisive role in stabilising aerosol acidity. In addition, the increase of the liquid water content (LWC) at the foot facilitates the gas-particle conversion of NH3, while the H+ concentration was diluted, resulting in a decrease in acidity at the foot. NH4+/NH3 had good linear correlations with SO42−, NO3－, and LWC during the daytime at both sites, indicating that SO42−, NO3－, and LWC together affect the gas-particle distribution of ammonia by day: however, the effect of LWC at night was not evident. © 2023, The Authors. All rights reserved.

关键词： Ammonia

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Unveiling the Unexpected C-C Dissociation Capacity and Intrinsic Mechanism of Undercoordinated Pd Cluster/Ceo2 for the Efficient and Stable Catalytic Mineralization of Propane

SSRN

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SSRN 2022年

作者： Xia, Lianghui Jian, Yanfei Wang, Jingjing Wang, Yao Chai, Shouning Liu, Yujie Li, Lu Yu, Yanke Albilali, Reem He, Chi State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University Shaanxi Xi’an710049 China Department of Chemistry College of Science Imam Abdulrahman Bin Faisal University P.O. Box 1982 Dammam31441 Saudi Arabia National Engineering Laboratory for VOCs Pollution Control Material & Technology University of Chinese Academy of Sciences Beijing101408 China

Light alkanes extensively presented in industrial exhausts have led tremendous harm to the atmospheric environment and human health. However, their stable molecule structure and inferior adsorption and activation efficiency make them as one category of the most intractable pollutants to be efficient controlled. Herein, we developed a Pd single cluster/CeO2 catalyst (Pd/CeO2-SCC-R) by a scalable deposition precipitation strategy, which demonstrates unexpected activity (propane total destructed below 300 oC) and thermal stability (even dramatically treated at 800 oC for multiple cycles) attributed to the strong metal-support interaction (SMSI) and unsaturated Pd metal sites caused by the shorter Pd-O distance. Mechanism studies determine that the Pd/CeO2-SCC-R possesses highly-efficient C-C cleavage ability owing to the persistent formation of large amounts of oxygen vacancies and low-coordinated Pd species, and the addition of H2O intrinsically accelerates propane activation and intermediate mineralization attributed to suppression of by-products by OH species. In comparison, the Pd single atom/CeO2 catalyst is preferentially for C-H bonds cleavage and inactive for C-C bonds cracking due to the saturated Pd sites anchored to the oxygen of supports directly, which generates more non-oxidation by-products as propyne and propylene, inhibiting the continuous decomposition of propane due to the retardatory oxidation of pyruvate species. The present work sheds critical insight to the production of fulfilling products through the directional cleavage of C-C/C-H bonds in the activation of light alkane molecules. © 2022, The Authors. All rights reserved.

关键词： Oxygen vacancies

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Research on control strategies for rapid load decrease events in fluoride salt reactor-supercritical CO2 Brayton cycle systems

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Nuclear engineering and Design 2025年 439卷

作者： Shichang, Yun Xinyu, Li Dalin, Zhang Ping, Song Wenxi, Tian Suizheng, Qiu Guanghui, Su 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 State Key Laboratory of Marine Thermal Power Technology Wuhan Second Ship Design and Research Institute Wuhan China

This study delves into the control strategies for the Fluoride-salt-cooled High-temperature Reactor-Supercritical CO2 (SCO2) Brayton cycle power generation system under rapid grid load reduction scenarios. By developing a dynamic simulation model, the system's dynamic response characteristics under rapid load changes were analyzed, and a combined control strategy emphasizing safety, speed, and economic efficiency was proposed. The research first compared the dynamic response characteristics and steady-state performance of different bypass configurations under load rejection conditions. The computational results indicate that all three bypass control systems exhibit excellent load-following capabilities, effectively responding to a 50 % load step change within 10 s. However, significant differences were observed in their steady-state thermodynamic performance: the upper cycle bypass control achieves the highest steady-state efficiency (η = 29.92 %), followed by the turbine bypass control (η = 27.50 %), with the heat source bypass control showing relatively lower efficiency (η = 26.49 %). Although the upper cycle bypass offers superior efficiency, it leads to a substantial increase in the working fluid flow through the compressor (ΔQ = 15 %) during operation, raising the risk of compressor blockage and necessitating additional flow restriction and anti-blocking interlock control systems. Considering system safety, control complexity, and engineering feasibility, the turbine bypass system, with its relative independence and lower operational risk, is deemed more suitable as the primary control strategy for load rejection conditions. Building on this, the study proposes a combined control strategy that leverages the strengths of both bypass control and inventory control. During the initial phase of rapid load reduction, the bypass control system quickly adjusts the turbine bypass valve opening to promptly respond to grid load changes, ensuring system frequency stability

关键词： Frequency stability

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Chlorine anchored pyrrole-based conjugated porous polymers for ultrahigh capacity and selective Hg(II) capture

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Separation and Purification Technology 2025年 374卷

作者： Bianyan He Jiarui Zhang Yubing Wang Mingtao Li Wei Yan Department of Environmental Science and Engineering Xi’an Key Laboratory of Solid Waste Recycling and Resource Recovery Xi’an Jiaotong University Xi’an 710049 PR China State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an 710049 PR China

In this study, chlorine anchored pyrrole-based conjugated porous polymers (CPPs) with distinct pore properties were synthesized using the Knoevenagel reaction and the double chain condensation method. The partially crosslinked and partially oxidized structures of the materials exhibit a unique microstructure integrating interconnected nets and molecular hooks. This architecture utilizes pore channels for physical interception of Hg(II), while synergistic chemical immobilization at N, O, and Cl active sites enables multifunctional enhancement of Hg(II) capture efficiency. Among these materials, the maximum adsorption capacity reached 1183 mg·g −1 , demonstrating ultrahigh selectivity. Moreover, the adsorbents maintained > 90 % removal efficiency over 10 adsorption–desorption cycles, confirming excellent reusability. Mechanistic studies revealed that Hg(II) adsorption primarily whin material pores through hydrogen bonding and coordination interactions, and their synergistic interactions. This work highlights the efficiency of the double chain condensation design strategy in advancing conjugated porous polymers for the removal of heavy metals, particularly Hg(II), from wastewater.

关键词： Conjugated porous polymers Synergistic adsorption Heavy metal ion Hg(II) capture

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Cavitation characteristics of rotary vane pump in aeroengine lubricating oil system and their effects on pump performance

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Hangkong Dongli Xuebao/Journal of Aerospace power 2025年第7期40卷

作者： Wang, Ge Wang, Yijin He, Denghui Yang, Lina Cao, Ming Bai, Bofeng State Key Laboratory of Eco-hydraulic in Northwest Arid Region of China Xi’an University of Technology Xi’an710048 China Department of Power Engineering Institute of Water Resources and Hydro-electric Engineering Xi’an University of Technology Xi’an710048 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China Commercial Aircraft Engine Company Limited Aero Engine Corporation of China Shanghai200241 China Shanghai Center of Research for Commercial Aircraft Engine Engineering Techniques Shanghai200241 China

To meet the demand for high-performance oil pumps in the lubricating oil system of high thrust and high-speed aeroengines, numerical simulation was conducted on a new high-speed rotary vane oil pump. The Mixture multiphase flow model, Singhal full cavitation model, and renormalization group（RNG） k-Ε turbulence model were employed for numerical calculation, and the reliability of the numerical simulation method was verified through experiments. Then, cavitation characteristics of the rotary vane pump and its impact on pump performance under different inlet pressure and oil temperature conditions were analyzed. The results showed that the cavitation gas was mainly distributed in the volume chamber on the oil suction side, as well as on the suction surface of the rotary vane and near the inner wall of the rotor. With the decrease of inlet pressure and the increase of oil temperature, the cavitation phenomenon inside the rotary vane pump intensified, and the cavitation gas increased, which in turn led to a decrease in the average oil discharge flow rate at the pump outlet and a decrease in volumetric efficiency. When the inlet pressure dropped to 40 kPa and the temperature rose to 373.15 K, the average oil discharge flow rate and volumetric efficiency at the pump outlet both significantly decreased. The pressure pulsation at the monitoring point exhibited low-frequency and high-amplitude pulsation characteristics. The cavitation of the rotary vane pump affected not only its oil discharge and volumetric efficiency, but also the stable and reliable operation of the pump. © 2025 Beijing University of Aeronautics and Astronautics (BUAA). All rights reserved.

关键词： Vane pumps

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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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PREFACE: SPECIAL ISSUE FOR THE 2ND INTERNATIONAL SYMPOSIUM ON THERMAL-FLUID DYNAMICS (ISTFD2021)

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Heat Transfer Research 2022年第8期53卷 V-VI页

作者： Cheng, Lixin Bai, Bofeng Guo, Zhixiong School of Energy and Power Engineering Beijing University of Technology Beijing100124 China Department of Engineering and Mathematics Sheffield Hallam University SheffieldS1 1WB United Kingdom State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China Department of Mechanical and Aerospace Engineering Rutgers The State University of New Jersey PiscatawayNJ08854 United States

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MgO and Au nanoparticle Co-modified g-C_(3)N_(4)photocatalysts for enhanced photoreduction of CO_(2)with H_(2)O

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Chinese Journal of Catalysis 2021年第5期42卷 781-794页

作者： Naixu Li Meiyou Huang Jiancheng Zhou Maochang Liu Dengwei Jing School of Chemistry and Chemical Engineering Southeast UniversityNanjing 211189JiangsuChina International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi’an Jiaotong UniversityXi’an 710049ShaanxiChina Jiangsu Key Laboratory for Biomass Energy and Material Institute of Chemical Industry of Forest ProductsChinese Academy of ForestryNanjing 210042JiangsuChina Suzhou Academy of Xi’an Jiaotong University Suzhou 215123JiangsuChina

The photoreduction of CO_(2)to achieve high-value-added hydrocarbons under simulated sunlight irradiation is advantageous,but *** this study,a series of MgO and Au nanoparticle-co-modified g-C_(3)N_(4)photocatalysts were synthesized and subsequently applied for the photocatalytic reduction of CO_(2)with H2O under simulated solar *** best photocatalytic performance was demonstrated by the Au and 3%MgO-co-modified g-C_(3)N_(4)photocatalysts with CO,CH_(4),CH3OH,and CH3CHO yields of 423.9,83.2,47.2,and 130.4μmol/g,respectively,in a 3-h *** investigated the effects of MgO and Au as cocatalysts on photocatalytic behaviors,*** characterizations and experimental results showed that the enhanced photocatalytic activity was due to the synergistic effect among the components of the ternary *** cocatalyst MgO can activate CO_(2)(adsorbed at the interface between the MgO and Au particles),and the Mg-N bonds formed in the MgO-CN nanosheets played an important role in the charge ***,the Au particles that were modified into MgO/g-C_(3)N_(4)can increase the absorption of visible light via the surface plasmon resonance effect and further reduce the activation energies of the photoreduction of CO_(2)using *** study provided an effective method for the modification of traditional primary photocatalysts with promising performance for photocatalytic CO_(2)reduction.

关键词： CO2 photoreduction MgO Au g-C3N4 Photocatalysis Synergistic effect Cocatalyst

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