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Study on performance of double helical capacitance probe for water fraction measurement in multiphase flow

AIP Conference Proceedings 2012年第1期1428卷 120-127页

作者： J. Ye L. J. Guo H. L. Zhou State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an China

A type of capacitance probe performance with two brass electrodes intertwined on the outer wall of insulation pipe like a double helix is investigated numerically in this paper, which can measure water fraction in air-oil-water two or three-phase flow in oil industry. The motivation of this paper is to optimize this kind of probe to improve its electric response and spatial resolution and so a 3-D numerical simulation using finite element method is employed to evaluate the effect of electrodes configuration of this capacitance probe on measuring water fraction in horizontal pipes. The electrostatic field of the probe is preliminarily analyzed referred to stratified flow of air-water two-phase flow regime. Several parameters are considered as main variables which have an important effect on the precision of the probe, such as central angle, position angle and length of the two electrodes. From the electrostatic field analysis, lumped capacitance between the two electrodes is obtained in every different electrode geometry model and the results of each model are compared to each other in order to select a better arrangement of the electrodes that has a better response to water fraction. And by using circuit simulation method, the numerical calculated lumped capacitance is transferred to voltage output through the circuit used in the experiment. The relationship between voltage and water fraction of calculated and experimental result are compared in order to test the reasonableness of the simulation. The results show that at high water fraction, the difference between numerical and measured data agrees very well.

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Large-eddy simulation of boundary layer separation and reattachment in low-pressure turbine cascade

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Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical engineering 2009年第29期29卷 77-83页

作者： Zhang, Di Shu, Jing Lan, Ji-Bing Xie, Yong-Hui State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 Shaanxi Province China

Large fraction of the low-pressure turbine cascade boundary layer is laminar flow due to low Reynolds number. High-lift low-pressure turbine blade leads to increase the adverse pressure gradient at rear of the turbine cascade. Boundary layer separation is easy to happen as the layer has low level of momentum and energy under large adverse pressure gradient, and then transition and reattachment occurs in the boundary layer. Large-eddy simulation (LES) was used to study boundary layer separation and reattachment in the low-pressure turbine (LPT) cascade without considering upstream wakes and at Reynolds numbers (based on chord length and throat exit velocity) of 5105. The numerical results agree with experimental measurements in terms of the time averaged static pressure distribution around the blade and the suction side boundary layer separated and reattached points. In addition, Separation and reattachment locations of suction side boundary layer were investigated with different inlet flow angle and different Reynolds numbers. The effect of the previous two parameters on boundary layer separation of cascade is obtained. © 2009 Chin. Soc. for Elec. Eng.

关键词： Large eddy simulation

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Laser-induced breakdown spectroscopy in Asia

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Frontiers of physics 2016年第6期11卷 231-255页

作者： Zhen-ZhenWang Yoshihiro Deguchi Zhen-Zhen Zhang Zhe Wang Xiao-Yan Zeng Jun-Jie Yan State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China Graduate School of Advanced Technology and Science Tokushima University Tokushima 770-8501 Japan State Key Lab of Power Systems Department of Thermal Engineering Tsinghua-BP Clean Energy Center Tsinghua University Beijing 100084 China Wuhan National Laboratory for Optoelectronics (WNLO) Huazhong University of Science and Technology Wuhan ~3007~ China

Laser-induced breakdown spectroscopy (LIBS) is an analytical detection technique based on atomic emission spectroscopy to measure the elemental composition. LIBS has been extensively studied and developed due to the non-contact, fast response, high sensitivity, real-time and multi-elemental detection features. The development and applications of LIBS technique in Asia are summarized and discussed in this review paper. The researchers in Asia work on different aspects of the LIBS study in fundamentals, data processing and modeling, applications and instrumentations. According to the current research status, the challenges, opportunities and further development of LIBS technique in Asia are also evaluated to promote LIBS research and its applications.

关键词： laser-induced breakdown spectroscopy (LIBS) quantitative analysis signal enhancement applications challenges

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Experimental Study on Heat Transfer Characteristics of Static Flash Evaporation Process

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Energy Procedia 2017年 105卷 4776-4781页

作者： Qingzhong Yang Dan Zhang Daotong Chong Yu Wang Junjie Yan State Key Laboratory of Multiphase Flow in Power Engineering School of Energy & Power Engineering Xi’an Jiaotong University Xi’an Shaan

An experimental study on flash evaporation process in static flash evaporation of aqueous NaCl solution was presented. Experiments were carried out with initial concentration of waterfilm varied from 0 to 0.15, initial height from 0.1 to 0.4 m, and superheat from 1.8 to 49.5 K. Instant superheat was the driving force during flash evaporation. A negative correlation was found between temperature drop rate and instant superheat. Instant heat transfer coefficient increased with the increase of instant superheat. A peak value of instant superheat existed during static flash. The evolution of instant superheat was affected by initial superheat, or initial height, or initial concentration of waterfilm.

关键词： Static flash evaporation Instant superheat Aqueous NaCl solution temperature drop rate

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Sand particle lift-off velocity measurements and numerical simulation of mass flux distributions in a wind tunnel

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Journal of Arid Land 2017年第3期9卷 331-344页

作者： XIAO Fengjun DONG Zhibao GUO Liejin WANG Yueshe LI Debiao National Demonstration Center for Experimental Geography Education College of Tourism and Environment Shaanxi Normal University Xi'an 710119 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China Xi'an Special Equipment Inspection Institute Xi'an 710065 China

Lift-off velocity of saltating sand particles in wind-blown sand located at 1.0 mm above the sand bed surface was measured using a phase Doppler particle analyzer in a wind tunnel. The results show that the probability distribution of lift-off velocity can be expressed as a lognormal function, while that of lift-off angle follows an exponential function. The probability distribution of lift-off angle conditioned for each lift-off velocity also follows an exponential function, with a slope that becomes steeper with increasing lift-off velocity. This implies that the probability distribution of lift-off velocity is strongly dependent on the lift-off angle. However, these lift-off parameters are generally treated as an independent joint probability distribution in the literature. Numerical simulations were carried out to investigate the effects of conditional versus independent joint probability distributions on the vertical sand mass flux distribution. The simulation results derived from the conditional joint probability distribution agree much better with experimental data than those from the independent ones. Thus, it is better to describe the lift-off velocity of saltating sand particles using the conditional joint probability distribution. These results improve our understanding of saltation processes in wind-blown sand.

关键词： lift-off velocity lift-off angle joint probability distribution sand mass flux saltation

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Local flow Regime Transition Criteria of Gas-Liquid Two-phase flow in Vertical Upward Tube with a Horizontal Rod

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Chinese Journal of Chemical engineering 2006年第4X期14卷 442-449页

作者：胡志华杨燕华刘磊周芳德 School of Mechanical Engineering Shanghai Jiaotong University Shanghai 200030 China State Key Laboratory of Multiphase Flow in Power Engineering Xi＇an Jiaotong Univeristy Xi＇an 710049 China

The upward multiphase cross flow and heat transfer in the vertical tube may occur in oil production and chemical facilities. In this study, the local flow patterns of an upward gas-water two phase cross flow in a vertical tube with a horizontal rod have been investigated with an optical probe and the digital high speed video system. The local flow patterns are defined as the bubble, slug, churn and annular flow patterns. Optical probe signals are ana- lyzed in terms of probability density function, and it is proved that the local flow patterns can be recognized by this method. The transition mechanisms between the different flow patterns have been analyzed and the corresponding transitional models are proposed. Finally, local flow pattern maps of the upward gas-water two-phase flow in the vertical tube with a horizontal rod are constructed.

关键词： gas-liquid two-phase cross flow local flow pattern transition

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A comparison of low-pressure premixed laminar flames of 1,3-butadiene and 1,3-butadiene/acetylene with synchrotron radiation 7

A comparison of low-pressure premixed laminar flames of 1,3-...

引用

7th Asia-Pacific Conference on Combustion, ASPACC 2009

作者： Wei, L.X. Wu, X.S. Chen, Z.Y. Huang, Z.H. Yuan, T. Li, Y.Y. Tian, Z.Y. State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China National Synchrotron Radiation Laboratory University of Science and Technology of China Hefei230029 China

Low-pressure premixed laminar flames of 1,3-butadiene/oxygen /argon and 1,3-butadiene+acetylene/oxygen/argon have been investigated with tunable synchrotron photoionization and molecular beam mass spectrometry. Flame species, including not only isomeric intermediates, but also those with same molecular weight while different formulae, are identified by measuring the ionization energies. Mole fraction profiles of the main species are derived from the measured signal intensities at different flame positions. Comparison between the two flames reveals that the existence of excessive acetylene in 1,3-butadiene flame can not lead to an obvious increase of aromatics formation under the condition investigated. © 2009 Combustion Institute. All rights reserved.

关键词： Acetylene

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Three-dimensional positioning method for moving particles based on defocused imaging using single-lens dual-camera system

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Chinese Optics Letters 2016年第3期14卷 42-46页

作者：周骛金娜贾敏华杨荟楠蔡小舒 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 Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education Southeast University

A method to three-dimensional position moving particles with one lens and two cameras is proposed. Two par- ticle images with different degrees of defocusing are adopted to solve the ambiguous problem of particle positions. A single-lens dual-camera system is developed to simultaneously capture these two images for the moving par- ticles. The measurement principles and theoretical analysis are introduced first, and then simulated investiga- tions and experimental research are discussed. The measurement errors in the simulations and experiments are less than 1% and 4%, respectively, in 20 times the depth of field of the system, which validates the feasibility of this method.

关键词： Optics Physics

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Reduction kinetics of SrFeO_(3−δ)/CaO∙MnO nanocomposite as effective oxygen carrier for chemical looping partial oxidation of methane

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Frontiers of Chemical Science and engineering 2022年第12期16卷 1726-1734页

作者： Xinhe Wang Liuqing Yang Xiaolin Ji Yunfei Gao Fanxing Li Junshe Zhang Jinjia Wei State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049China School of Chemical Engineering and Technology Xi’an Jiaotong UniversityXi’an 710049China Institute of Clean Coal Technology East China University of Science and TechnologyShanghai 200237China Department of Chemical and Biomolecular Engineering North Carolina State UniversityRaleighNC 27695USA

Chemical looping reforming of methane is a novel and effective approach to convert methane to syngas,in which oxygen transfer is achieved by a redox *** lots of efforts have been made to develop high-performance redox materials,a few studies have focused on the redox *** this work,the kinetics of SrFeO_(3−δ)–CaO∙MnO nanocomposite reduction by methane was investigated both on a thermo-gravimetric analyzer and in a packed-bed *** the methane reduction,combustion occurs before the partial oxidation and there exists a transition between *** weight loss due to combustion increases,but the transition region becomes less inconspicuous as the reduction temperature *** weight loss associated with the partial oxidation is much larger than that with *** rate of weight loss related to the partial oxidation is well fitted by the Avrami–Erofeyev equation with n=3(A3 model)with an activation energy of 59.8 kJ∙mol^(‒1).The rate law for the partial oxidation includes a solid conversion term whose expression is given by the A3 model and a methane pressure-dependent term represented by a power *** partial oxidation is half order with respect to methane *** proposed rate law could well predict the reduction kinetics;thus,it may be used to design and/or analyze a chemical looping reforming reactor.

关键词： chemical looping reforming SrFeO_(3−δ) CaO·MnO nanocomposite reduction kinetics Avrami–Erofeyev model pressure-dependent term

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Research on the Preparation of (CuAg)xIn2xZn2(1−2x)S2 Solid Solution Photocatalysts

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AIP Conference Proceedings 2010年第1期1207卷 1066-1069页

作者： K. Zhang D. W. Jing C. J. Xing L. J. Guo State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University China

ZnS‐CuInS2‐AgInS2 solid solution photocatalysts were successfully prepared by co‐precipitation method with heat treatment under different atmosphere ( N2 and H2S). XRD, XRF, UV‐vis, and SEM were used to characterize the prepared photocatalysts, indicated that the composition of result photocatalysts were different from each other and also the rate of charge, though they possessed a wurtzite‐type phase structure. The photocatalysts all showed photocatalytic activities for H2 evolution from aqueous solutions containing SO32− and S2− as sacrificial reagents under visible light irradiation with Ru loading, but sample treated under H2S atmosphere performed better, the possible reason was proposed.

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