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Research of the Gas-solid Flow Character Based on the DEM Method

Journal of Thermal Science 2011年第6期20卷 521-526页

作者： Xueyao Wang and Yunhan Xiao Research Center for Clean energy and power,chinese academy of sciences key laboratory of advanced energy and power,chinese academy of sciences (Institute of Engineering Thermophysics),beijing,100190,china Research Center for Clean energy and power Chinese Academy of Sciences Beijing China key laboratory of advanced energy and power Chinese Academy of Sciences (Institute of Engineering Thermophysics) Beijing China

Numerical simulation of gas-solid flow behaviors in a rectangular fluidized bed is carried out three dimensionally by the discrete element method (DEM).Euler method and Lagrange method are employed to deal with the gas phase and solid phase *** collided force among particles,striking force between particle and wall,drag force,gravity,Magnus lift force and Saffman lift force are considered when establishing the mathematic ***-sphere model is used to describe the collision of *** addition,the Euler method is also used for modeling the solid phase to compare with the results of *** flow patterns,particle mean velocities,particles' diffusion and pressure drop of the bed under typical operating conditions are *** results show that the DEM method can describe the detailed information among particles,while the Euler-Euler method cannot capture the micro-scale *** matter which method is used,the diffusion of particles increases with the increase of gas *** the gathering and crushing of particles cannot be simulated,so the energy loss of particles' collision cannot be calculated and the diffusion by using the Euler-Euler method is *** addition,it is shown by DEM method,with strengthening of the carrying capacity,more and more particles can be schlepped upward and the dense suspension upflow pattern can be ***,the results given by the Euler-Euler method are not consistent with the real situation.

关键词： DEM gas-solid flow numerical simulation

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Unsteady Numerical Simulation of Hot Streak/Blades Interaction and Film Cooling

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Journal of Thermal Science 2010年第5期19卷 402-409页

作者： Weilin Yi,Lucheng Ji and Yunhan Xiao Research Center for energy and power,chinese academy of sciences,beijing,china key laboratory of advanced energy and power,chinese academy of sciences,(Institute of Engineering Thermophysics),beijing,china P.O.Box 2706,beijing 100190,china Research Center for energy and power Chinese Academy of Sciences Beijing China key laboratory of advanced energy and power Chinese Academy of Sciences (Institute of Engineering Thermophysics) Beijing China beijing China

Deeply research on management and application of hot streak is an important way to breakthrough technique obstacle of aero engine hot *** method is a useful instrument to investigate the correlative *** the paper developed independently three dimensional unsteady parallel computational code-MpiTurbo based on Fortran 90 and MPI at Linux operating *** unsteady numerical simulation was carried out to investigate impacts of the factors,which included circumferential locations of hot streak and clocking positions of blade rows,on the thermal environment of a 1+1 counter-rotating *** results clearly indicated that clocking positions of hot streak/blade row and blade row/blade row had great influence on the time-averaged temperature distribution of the third blade ***,it can be effective for improving thermal environment of turbine to optimize blade parameters and clocking *** film cooling layout was designed by the repetitious steady simulation based on source term *** the flow structure detail was given by the unsteady simulation.

关键词： hot streak turbine parallel computation film cooling

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Exploration of combined adjustment laws about IGV,stator and rotational speed in off-design conditions in an axial compressor

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中国科学：技术科学英文版 2010年第4期53卷 969-975页

作者： HU YanMing1,2 & NIE ChaoQun1 1 key laboratory of advanced energy and power Technology,Institute of Engineeting Thermophysics,chinese academy of Science,beijing 100190,china 2 Graduate School of chinese academy of sciences,beijing 100190,china 1. key laboratory of advanced energy and power Technology Institute of Engineeting Thermophysics Chinese Academy of Science Beijing 100190 China2. Graduate School of Chinese Academy of Sciences Beijing 100190 China

Experimental investigations are performed in a three-stage low-speed axial compressor with variable inlet guide vanes(IGV) and adjustable *** characteristics of the compressor,especially the efficiency and stall margin,are analyzed in design and off-design operation conditions by adjusting stagger angles of IGV and stators as well as changing the rotational *** experimental results show that the off-design performance of the multistage axial compressor is improved by restaggering of IGV and stators related to rotational *** the background of engineering applications,digital signal processing(DSP) technique is used to realize online adjustment of stagger angles according to the corresponding relations between incidence angles of rotor and rotational speed.

关键词： axial compressor IGV surge DSP techniques off-design

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Simulation of aerodynamic performance affected by vortex generators on blunt trailing-edge airfoils

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Science china(Technological sciences) 2010年第1期53卷 1-7页

作者： YANG Ke1,2,ZHANG Lei1,3 & XU JianZhong1,2 1 Institute of Engineering Thermophysics,chinese academy of sciences,beijing 100190,china 2 key laboratory of Wind energy Utilization,chinese academy of sciences,beijing 100190,china 3 Graduate School of chinese academy of sciences,beijing 100190,china 1. Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing 100190 China2. Key Laboratory of Wind Energy Utilization Chinese Academy of Sciences Beijing 100190 China3. Graduate School of Chinese Academy of Sciences Beijing 100190 China

An investigation was carried out by numerical simulation on a wind turbine airfoil and a blunt trailing-edge airfoil with and without vortex generators (VGs), and the performance of the airfoils was analyzed. By the simulation of airfoil DU 91-W2-250 it was verified that the numerical method and model were credible. Based on this airfoil, a new one with a blunt trailing edge of 6% chord was blended by symmetrically adding thickness, and its characteristics curves were obtained through computing at key angles of attack. Additionally, the pressure distribution on blended airfoil was analyzed by comparing to the airfoil without blend. The interaction of streamwise vortices induced by VGs with trailing vortex or separation vortex was considered, followed by the uncovery of how VGs can suppress the boundary layer separation.

关键词： vortex generators airfoil blunt trailing-edge

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The Simulation and Experimental Validation on Gas-Solid Two Phase Flow in the Riser of a Dense Fluidized Bed

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Journal of Thermal Science 2009年第2期18卷 137-141页

作者： Xue-yao Wang Fan Jiang Xiang Xu Sheng-dian Wang Bao-guo Fan Yun-han Xiao key laboratory of advanced energy and power, chinese academy of sciences (Institute of Engineering Thermophysics) beijing 100190 key laboratory of advanced energy and power Chinese Academy of Sciences (Institute of Engineering Thermophysics) Beijing 100190 China

Gas-solid flow in dense CFB (circulating fluidized bed)) riser under the operating condition, superficial gas 15.5m/s and solid flux 140 kg/m2s using Geldart B particles (sand) was investigated by experiments and CFD (computationalfluid dynamics) simulation. The overall and local flow characteristics are determined using the axialpressure profiles and solid concentration profiles. The cold experimental results indicate that the axial solid concentration distribution contains a dilute region towards the up-middle zone and a dense region near the bottomand the top exit zones. The typical core-annulus structure and the back-mixing phenomenon near the wall of theriser can be observed. In addition, owing to the key role of the drag force of gas-solid phase, a revised drag forcecoefficient, based on the EMMS (energy-minimization multi-scale) model which can depict the heterogeneouscharacter of gas-solid two phase flow, was proposed and coupled into the CFD control equations. In order to findan appropriate drag force model for the simulation of dense CFB riser, not only the revised drag force model butsome other kinds of drag force model were used in the CFD. The flow structure, solid concentration, clustersphenomenon, fluctuation of two phases and axial pressure drop were analyzed. By comparing the experimentwith the simulation, the results predicted by the EMMS drag model showed a better agreement with the experimentalaxial average pressure drop and apparent solid volume fraction, which proves that the revised drag forcebased on the EMMS model is an appropriate model for the dense CFB simulation.

关键词： riser gas-solid flow drag force EMMS model

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Synthesis,characterization,and thermostability of bis(2,2,6,6-tetramethyl-3,5-heptanedionato)copper(Ⅱ)

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Rare Metals 2012年第4期31卷 343-349页

作者： ZHANG Teng,GU Hongwei,DING Fazhu,QU Fei,and DAI Shaotao key laboratory of Applied Superconductivity,Institute of Electrical Engineering,chinese academy of sciences,beijing 100190,china key laboratory of Applied Superconductivity Institute of Electrical Engineering Chinese Academy of Sciences Beijing China

Owing to the adaptability to large scale processing,excellent composition control and film uniformity,the metal-organic chemical vapor deposition（MOCVD） technique is a promising process for high-temperature superconductor YBa;Cu;O;（YBCO） *** this technique,the evaporation characteristics and thermostability of adopted precursors in whole process will decide the quality and reproducible results of YBCO *** the present report,bis（2,2,6,6-tetramethyl-3,5-heptanedionato）copper（II）(Cu（TMHD）;) was synthesized by the interaction of copper acetate hydrate with TMHD in methanol solution,and its structure was identified by FTIR,1 H NMR,and EI-MS ***,thermal property and the kinetics of decomposition were systematically investigated by nonisothermal thermogravimetric analysis methods（TGA） at different heating rates in streams of N;,and the average apparent activation energy of evaporation process was evaluated by the Ozawa,Kissinger,and Friedman *** possible conversion function was estimated through the Coats-Redfern method to characterize the evaporation patterns and followed a phase boundary reaction mechanism by the contracting area equation with average activation energy of 85.1 kJ·mol;.

关键词： Cu(TMHD)_2 metal-organic chemical vapor deposition(MOCVD) synthesis thermostability

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Direct numerical simulation of shock/turbulent boundary layer interaction in a supersonic compression ramp

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Science china(Physics,Mechanics & Astronomy) 2010年第9期53卷 1651-1658页

作者： LI XinLiang1,FU DeXun2,MA YanWen2 & LIANG Xian1 1 key laboratory of High Temperature Gas Dynamics,Institute of Mechanics,chinese academy of sciences,beijing 100190,china 2 The State key laboratory of Nonlinear Mechanics,Institute of Mechanics,chinese academy of sciences,beijing 100190,china 1. key laboratory of High Temperature Gas Dynamics Institute of Mechanics Chinese Academy of Sciences Beijing 100190 China2. The State Key Laboratory of Nonlinear Mechanics Institute of Mechanics Chinese Academy of Sciences Beijing 100190 China

A direct numerical simulation of the shock/turbulent boundary layer interaction flow in a supersonic 24-degree compression ramp is conducted with the free stream Mach number *** blow-and-suction disturbance in the upstream wall boundary is used to trigger the *** the mean wall pressure and the velocity profiles agree with those of the experimental data,which validates the *** turbulent kinetic energy budget in the separation region is *** show that the turbulent production term increases fast in the separation region,while the turbulent dissipation term reaches its peak in the near-wall *** turbulent transport term contributes to the balance of the turbulent conduction and turbulent *** on the analysis of instantaneous pressure in the downstream region of the mean shock and that in the separation bubble,the authors suggest that the low frequency oscillation of the shock is not caused by the upstream turbulent disturbance,but rather the instability of separation bubble.

关键词： compression ramp shock/turbulent boundary layer interaction direct numerical simulation shock oscillation

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The establishment of crystal position look-up table for positron emission tomography with block detectors

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Science china(Technological sciences) 2009年第8期52卷 2418-2423页

作者： CHAI Pei1,2 & SHAN BaoCi1 1 key laboratory of Nuclear Analytical Techniques, Institute of High energy Physics, chinese academy of sciences, beijing 100049, china 2 Graduate University of chinese academy of sciences, beijing 100049, china key laboratory of Nuclear Analytical Techniques Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China Graduate University of chinese academy of sciences Beijing 100049 China

A method has been developed to establish the crystal position look-up table for positron emission tomography with block detectors. It is based on the principle that the counts in crystal position histogram obey the Gaussian mixture model (GMM). This method has taken full consideration of the characteristics of the GMM and the detector itself. The experimental results have proved that it is simple, reliable, and universal.

关键词： positron emission tomography position look-up table 2-D position histogram

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Geometry of Broad Line Regions of Active Galactic Nuclei

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chinese Journal of Astronomy and Astrophysics 2008年第1期8卷 50-62页

作者： Xiao-Rong Lü1 key laboratory for Particle Astrophysics, Institute of High energy Physics, chinese academy of sciences, beijing 100049 2 Graduate School of chinese academy of sciences, beijing 100049 key laboratory for Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 and Graduate School of chinese academy of sciences Beijing 100049

It has long remained an open question as to the geometry of the broad line region （BLR） in active galactic nuclei （AGNs）. The reverberation mapping technique which measures the response of the broad emission lines to the ionizing continuum, when combined with multiwavelength continuum fitted by sophisticated accretion disks, provides a way of probing the BLR geometry. We analyze a sample of 35 AGNs, which have been monitored by the reverberation mapping campaign. In view of energy budget, the reverberation-based BH masses are found to be in agreement with those obtained by accretion disk models in two thirds of the present sample while the reverberation mapping methods underestimate the BH masses in about one third of objects, as also suggested by CoUin et al. in a recent work. We point out that there are obviously two kinds of BLR geometry, which are strongly dependent on the Eddington ratio, and separated by the value LBol/LEdd - 0.1. These results prefer a scenario of the disk and wind configuration of the BLR and identify the Eddington ratio as the physical driver regulating the wind in the BLR.

关键词： accretion, accretion disks - galaxies active - galaxies Seyfert - quasars general

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Narrow line Seyfert 1 galaxies: where are the broad line regions?

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Science china(Physics,Mechanics & Astronomy) 2010年第12期53卷 2307-2311,2339-2343页

作者： MAO WeiMing 1,2,3 , HU Chen 2 , WANG JianMin 2 , BIAN WeiHao 4 , ZHANG Shu 2 & ZHAO Gang 1 1 key laboratory of Optical Astronomy, National Astronomical Observatories, chinese academy of sciences, beijing 100012, china 2 key laboratory for Particle Astrophysics, Institute of High energy Physics, chinese academy of sciences, beijing 100049, china 3 Graduate University of the chinese academy of sciences, beijing 100049, china 4 Department of Physics, Nanjing Normal University, Nanjing 210011, china 1. key laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China2. Key Laboratory for Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China3. Graduate University of the Chinese Academy of Sciences Beijing 100049 China4. Department of Physics Nanjing Normal University Nanjing 210011 China

A sample consisting of 211 narrow line Seyfert 1 galaxies (NLS1s) with high quality spectra from the Sloan Digital Sky Survey (SDSS) is selected to explore where broad line regions are in these objects. We find that the Hβ profile can be fitted well by three (narrow, intermediate and broad) Gaussian components, and the FWHM ratios of the broad to the intermediate components hold a constant of 3.0 roughly for the entire sample. If the broad components originate from the region scaled by the well-determined Hβ reverberation mapping relation, we find that the intermediate components originate from the inner edge of the torus, which is scaled by dust K-band reverberation. We find that the IC and the BC are strongly linked dynamically, but the relation of their covering factors is much more relaxed, implying that both regions are clumpy.

关键词： black hole physics galaxies: evolution quasars: general

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