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A numerical simulation on the infrared radiation of hot exhausting nozzles with a coupled flow and heat transfer model

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Science china(Technological Sciences) 2010年第10期53卷 2699-2707页

作者： HU HaiYang1.& WANG Qiang2 1.china Academy of Aerospace Aerodynamics, {1. 1.0074, china 2 school of jet propulsion, beihang University, {1. 1.01.1, china 1. china Academy of Aerospace Aerodynamics Beijing 100074 China2. School of Jet Propulsion Beihang University Beijing 100191 China

A coupled model among flow field,solid temperature,species concentration and gas radiation,which was based on statistical narrow-band correlated-k model,was employed to predict the infrared radiations from hot exhausting nozzles. The parameters of narrow-band model were deduced from HITEMP line-by-line database. Several methods to increase computational efficiency and to save computational resources were employed,thus all the complicated computations could be operated on a personal computer. The predictions for three cases have been conducted to validate the accuracy of the methods mentioned above,including the temperature distribution of a water-cooling nozzle in rocket engines,the carbon dioxide absorptivity at the wavelength of 4.3 micron and the infrared radiation of a cylindrical furnace. Finally,the aerothermodynamic and infrared characteristics of two nozzles were predicted. It was shown that the infrared radiation intensity of chevron ejecting nozzle were obviously smaller than that of common axisymmetric convergent-divergent nozzle.

关键词： infrared radiation numerical simulation exhausting nozzles coupled model

Application and Comparison of SST Model in Numerical Simulation of the Axial Compressors

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Journal of Thermal Science 2010年第4期19卷 300-309页

作者： YIN Song~1.JIN Donghai~2,GUI Xingmin~3 and ZHU Fang Aero-Engines Simulation Research Center,school of {1. propulsion,beijing University of Aeronautics and Astronautics, beijing,1.01.1.china Aero-Engines Simulation Research Center School of Jet Propulsion Beijing University of Aeronautics and Astronautics Beijing China

The shear-stress transport(SST)turbulence model is incorporated into Navier-Stokes equations to simulate a turbomachinery flowfield.A staggered finite volume method is used to make the mean flow equations and turbulence model equations strongly coupled and enhance the stability of the numerical *** implicit treatment of the source terms is applied to the SST model.A steady state solution is obtained using five-stage Runge-Kutta time-stepping scheme with local time stepping and residual smoothing to accelerate convergence. The wall distance d,a key parameter in the SST model,is solved by a partial differential *** validations of the code are conducted on rotor 37,wp1. at design and off-design conditions by comparison with measurements and the Spalart-Allmaras(SA)turbulence *** flow within the tip is calculated with a multi-block grid.

关键词： SST model staggered finite volume method turbomachinery simulation multi-block grid

Application of Tandem Cascade to Design of Fan Stator with Supersonic Inflow

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Chinese Journal of Aeronautics 2010年第1期23卷 9-14页

作者： Li Qiushi,Wu Hong,Zhou Sheng school of {1. propulsion,beijing University of Aeronautics and Astronautics,beijing 1.01.1.china [a] school of {1. propulsion Beijing University of Aeronautics Astronautics Beijing 100191 China

This article proposes a tandem cascade constructed to tackle the thorny problem of designing the high-loaded stator with a supersonic inflow and a large turning angle. The front cascade adopts a supersonic profile to reduce the shock wave intensity turning the flow into subsonic,while the rear cascade adopts a subsonic profile with a large camber offering the flow a large turning angle. It is disclosed that the losses would be minimized if the leading edge of the rear cas- cade lies close to the pressure side of the front cascade at a distance of 20% pitch in pitch-wise direction without either axial spacing or overlapping in axial direction. The 2D numerical test results show that,with the inflow Mach number of 1.25 and the turning angle of 52° ,the total pressure loss coefficient of the tandem cascade reaches 0. 1.6 ,and the diffusion factor 0. 745. Finally,this article has designed and simulated a high-loaded fan stage with the proposed tandem stator,which has the pressure ratio of 3.1. and the efficiency of 86.32% at the rotor tip speed of 495.32 m/s.

关键词： fan/compressor tandem cascade stator supersonic inflow

Complex conforming Delaunay triangulation

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Science china(Information Sciences) 2010年第6期53卷 1130-1140页

作者： MENG XianHai 1. LI JiGang 1. YANG Qin 1. CAI Qiang 2 & CHEN QiMing 3 1.NLSDE, school of Computer Science and Engineering, {1. University, beijing 1.0083, china 2 school of Computer Sciences, beijing Technology and Business University, beijing 1.0037, china 3.school of Mechanical Engineering and Automation, {1. University, beijing 1.0083, china 1. NLSDE School of Computer Science and Engineering BeiHang University Beijing 100083 China2. School of Computer Sciences Beijing Technology and Business University Beijing 100037 China3. School of Mechanical Engineering and Automation BeiHang University Beijing 100083 China

A novel algorithm of conforming Delaunay triangulation for curved geometry is presented in the paper.A progress has been made for the problem puzzled Delaunay refinement where curved constraints cannot be accepted as input *** algorithm is based on a new sufficient condition for the existence of constraints in *** requires computing only the intersection between constraints and Voronoi edges or faces instead of the circum-sphere of curved *** the termination of the algorithm when small input angles exist in constraints, a weighted method is applied to ensure that the algorithm can terminate under any *** two-dimensional and three-dimensional results are also *** is shown that the algorithm has the capability of dealing with both linear and nonlinear constraints in a consistent way, without the need of maintaining triangular meshes on face constraints.

关键词： mesh generation Delaunay triangulation conforming curved constraints tetrahedralization weight

Local heat transfer measurements on a rotating flat blade model with a single film hole

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Progress in Natural Science:Materials International 2009年第3期19卷 321-330页

作者： Guoqiang Xu, Bin Yang*, Zhi Tao, Zhenming Zhao, Hongwei Wu National Key Laboratory on Aero-Engines, school of {1. propulsion, beihang University, beijing 1.0083, china [a]National Key Laboratory on Aero-Engines School of Jet Propulsion Beihang University Beijing 100083 China

An experimental study was performed to measure the heat transfer coeffcient distributions on a flat blade model under rotating oper-ating conditions. A steady-state thermochromic liquid crystal technique was employed to measure the surface temperature, and all the signals from the rotating reference frame were collected by the telemetering instrument via a wireless connection. Both air and CO2 were used as coolant. Results show that the rotational effect has a significant influence on the heat transfer coeffcient distributions. The pro-files of hg/h0, which is the ratio of heat transfer coeffcient with film cooling to that without film cooling, deffect towards the high-radius locations on both the pressure surface and suction surface as the rotation number (Rt) increases, and the deffective tendency is more evident on the suction surface. The variations in mainstream Reynolds number (ReD) and blowing ratio (M) present different distribu-tions of hg/h0 on the pressure and suction surfaces, respectively. Furthermore, the coolant used for CO2 injection is prone to result in lower heat transfer coeffcients.

关键词： Film cooling Heat transfer Flat blade Rotating

Complexity of synthesis of composite service with correctness guarantee

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Science china(Information Sciences) 2012年第3期55卷 638-649页

作者： DENG Ting1.2 , HUAI JinPeng1.3 & WO TianYu1.3 1.tate Key Laboratory of Software Development Environment, beihang University {1. 1.01.1, china 2school of Mathematics and System Science, beihang University, {1. 1.01.1, china 3school of Computer Science and Engineering, beihang University, {1. 1.01.1, china 1. State Key Laboratory of Software Development Environment Beihang University Beijing 100191 China2. School of Mathematics and System Science Beihang University Beijing 100191 China3. School of Computer Science and Engineering Beihang University Beijing 100191 China

How to compose existing web services automatically and to guarantee the correctness of the design (e.g. temporal constraints specified by temporal logic LTL, CTL or CTL*) is an important and challenging problem in web services. Most existing approaches use the process in conventional software development of design, verification, analysis and correction to guarantee the correctness of composite services, which makes the composition process both complex and time-consuming. In this paper, we focus on the synthesis problem of composite service; that is, for a given set of services and correctness constraint specified by CTL or CTL* formula, a composite service is automatically constructed which guarantees that the correctness is ensured. We prove that the synthesis problem for CTL and CTL* are complete for EXPTIME and 2EXPTIME, respectively. Moreover, for the case of synthesis failure, we discuss the problem of how to disable outputs of environment (i.e. users or services) reasonably to make synthesis successful, which are also proved complete for EXPTIME and 2EXPTIME for CTL and CTL*, respectively.

关键词： business protocol composite service synthesis environment branching temporal logic

A spatio-velocity model based semantic event detection algorithm for traffic surveillance video

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Science china(Technological Sciences) 2010年第S1期53卷 120-125页

作者： SHENG Hao 1.ZHAO HuiJie 1.HUANG Jian 2 & LI Na 1.1.school of Instrument Science and Opto-Electro Engineering,{1. University,beijing 1.01.1.china 2 school of Software,{1. University,beijing 1.01.1.china 1. school of Instrument Science and Opto-Electro Engineering Beijing University Beijing 100191 China 2. school of Software Beijing University Beijing 100191 China

Detection of vehicle events is a research hotspot in digital *** this paper,an approach is proposed to detect vehicle events with semantic analysis of traffic surveillance video using spatio-velocity statistic *** approach includes two successive phases:trajectory clustering and semantic events *** trajectory clustering,a statistic model of vehicle trajectories are presented,for which a spatio-velocity model is trained by analyzing the trajectories of moving vehicles in the *** on the trajectory,which represents both the position of the vehicle and its instantaneous velocity,a trajectory similarity measure is ***,an improved hierarchical clustering algorithm is adopted to cluster the trajectories according to different spatial and velocity *** each cluster,trajectories that are spatially close have similar velocities of motion and represent one type of activity *** the semantic events detection phase,statistic models of semantic regions in the scene are generated by estimating the probability density and velocity distributions of each type of activity ***,semantic events are detected by the proposed spatio-velocity statistic *** paper also presents experiments using real video sequence to verify the effectiveness of the proposed method.

关键词： trajectory clustering spatio-velocity statistic model event detection digital traffic

3D building modeling,organization and application in digital city system

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中国科学：技术科学英文版 2010年第S1期53卷 134-142页

作者： YANG Xue 1.WENG JingNong 1.2,XIA YuBin 2,WU Lun 3 & SUI ZhengWei 3 1.College of Software,beihang University,{1. 2 College of Computer,beihang University,{1. 3 Institute of Remote Sensing and GIS,Peking University,beijing 1.0871.china beihang Univ Coll Software Beijing 100191 Peoples R China beihang Univ Coll Comp Beijing 100191 Peoples R China Peking Univ Inst Remote Sensing & GIS Beijing 100871 Peoples R China

The real world is a three-dimensional(3D)space requiring that 3D geospatial information applications be developed in alignment with the observer’s visual and perceptive ***,3D building model data are required in a wide range of areas such as urban planning,environmental protection,real estate management and emergency *** the same time,the development of Web service[LU1.technologies allows the possibility of the widely distributed 3D geospatial data on the web.3D city building model with its related information is an important part in the construction of a digital city system,and has become a staple resource on the web *** view of the hierarchical representation of a 3D building model,an abstract of a 3D building model based on structure details is studied,and a novel representation approach named 3D transparent building hierarchical model is presented in this *** approach fully uses both the existing 3D modeling technologies and CAD constructing mapping *** the spatial relationship description,structural components inside a building can be represented and integrated as hierarchical models in a unified 3D *** addition,based on the characteristics of the 3D building model data,a service-oriented architecture and Web service technologies for 3D city building models are *** aim of the approach is that 3D city building models can be used as a kind of data resource service on the web,and can also exist independently in various different web applications.

关键词： 3D modeling 3D transparent building hierarchical models china Star web services

Review of prediction for thermal contact resistance

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Science china(Technological Sciences) 2010年第7期53卷 1798-1808页

作者： WANG AnLiang1.& ZHAO JianFeng2 1.school of Astronautics, {1. University, beijing 1.01.1, china china Academy of Space Technology, beijing 1.0094, china 1. school of Astronautics Beihang University Beijing 100191 China2. China Academy of Space Technology Beijing 100094 China

Theoretical prediction research on thermal contact resistance is reviewed in this paper. In general, modeling or simulating the thermal contact resistance involves several aspects, including the descriptions of surface topography, the analysis of micro mechanical deformation, and the thermal models. Some key problems are proposed for accurately predicting the thermal resistance of two solid contact surfaces. We provide a perspective on further promising research, which would be beneficial to understanding mechanisms and engineering applications of the thermal contact resistance in heat transport phenomena.

关键词： thermal contact resistance thermal contact conductance surface topography deformation assumption prediction model numerical simulation