检索结果-南通市图书馆

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

在线全文

学校读者我要写书评

暂无评论

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 {2. 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 {2. 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

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

在线全文

学校读者我要写书评

暂无评论

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,{2. Academy of sciences,beijing 100190,china 2.The State key laboratory of Nonlinear Mechanics,Institute of Mechanics,{2. 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 2.-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

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

在线全文

学校读者我要写书评

暂无评论

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 {2. key laboratory of Advanced energy and Power,chinese Academy of {2. (Institute of Engineering Thermophysics),beijing,100190,china Research Center for Clean energy and Power Chinese Academy of Sciences Beijing China key laboratory of Advanced {2. 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

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

在线全文

学校读者我要写书评

暂无评论

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 {2.,beijing,china key laboratory of Advanced energy and Power,chinese Academy of {2.,(Institute of Engineering Thermophysics),beijing,china P.O.Box 2.06,{12.,china Research Center for energy and Power Chinese Academy of Sciences Beijing China key laboratory of Advanced {2. 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

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

在线全文

学校读者我要写书评

暂无评论

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 {2. 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

Nonlinear interactions between gravity waves and background winds

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2007年第6期17卷 639-644页

作者： Liu Xiao1,2.and Xu Jiyao1(1. State key laboratory for Space Weather, Center for Space Science and Applied Research, {2. Academy of sciences, beijing 100080, china 2. Graduate University of {2. Academy of sciences, beijing 100039, china) [a]State key laboratory for Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences Beijing China [b]Graduate University of chinese Academy of sciences Beijing China

Using the nonlinear propagating gravity waves (GW) model in the two-dimensional compressible atmosphere and the linear GW theory, the process of GW propagation in different background winds, e.g. the direction of the background wind is opposite to (dead wind) or the same as (tail wind) the direction of the horizontal phase velocity of GW, is studied. The results show that the dead wind prolongs the vertical wavelength and accelerates GW propagation. Therefore, GW propagates up to a higher height becomes instable in a short time and eventually induces an inverse jet flow. Then, the vertical wavelength is becoming short due to the nonlinear interactions between GW and the inverse jet flow. The vertical wavelength and group velocity decrease after GW propagates into the tail wind. The initial instable time is delayed. Although most of GW is trapped in the instable region, some of GW propagates above the instable region. Compared with GW propagation in the tail wind, the nonlinear interactions between GW and the dead wind are also strong. In contrast, the linear GW theory predicts that GW can propagate freely in the dead wind. The vertical wavelength simulated by the nonlinear numerical model is different from that predicted by the linear theory greatly after GW propagates into the dead wind.

关键词： gravity waves background winds vertical group velocity vertical wavelength nonlinear interactions.

Compression behavior of Zr_(41)Ti_(14)Cu_(12.5)Ni_(10)Be_(2..5) bulk metallic glass up to 2. GPa

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2005年第3期48卷 319-324页

作者： LI Gong 1, 2., ZHAN Zaiji 2., LIU Jing 3 , YUN Jinku 1 , SUN Liling 2., LIU Riping 1 , ZHANG Jun 2.& WANG Wenkui 1, 2.1. key laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, {2. 2. Center for Condensed Matter Physics, Institute of Physics, chinese Academy of sciences, beijing 100080, {2. 3. BSRF, Institute of High energy Physics, chinese Academy of sciences, beijing 100039, {2. 1. key laboratory of Metastable Materials Science and Technology Yanshan University 066004 Qinhuangdao China 2. Center for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences 100080 Beijing China 3. BSRF Institute of High Energy Physics Chinese Academy of Sciences 100039 Beijing China

The compression of a Zr41Ti14Cu12.5Ni10Be2..5 bulk metallic glass (BMG) is investigated at room temperature up to 2. GPa using in-situ high pressure energy dispersive X-ray diffraction with a synchrotron radiation source. The pressure-induced structural relaxation is exhibited. It is found that below about 8 GPa, the existence of excess free volume contributes to the rapid structural relaxation, which gives rise to the rapid volumetric change, and the structural relaxation results in the structural stiffness under higher pressure.

关键词： bulk metallic glass, high pressure, structural relaxation, synchrotron radiation.

Geometry of Broad Line Regions of Active Galactic Nuclei

在线全文

学校读者我要写书评

暂无评论

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 {2. 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

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

在线全文

学校读者我要写书评

暂无评论

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, {2. Academy of sciences, beijing 100012. china 2.key laboratory for Particle Astrophysics, Institute of High energy Physics, {2. Academy of sciences, beijing 100049, china 3 Graduate University of the {2. Academy of sciences, beijing 100049, china 4 Department of Physics, Nanjing Normal University, Nanjing 2.0011, 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 2.1 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