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直径30cm圆柱的气动力参数和绕流特性研究 被引量:12
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作者 沈国辉 姚剑锋 +2 位作者 郭勇 邢月龙 楼文娟 《振动与冲击》 EI CSCD 北大核心 2020年第6期22-28,共7页
为研究光滑圆柱的气动力系数和绕流特性,在均匀流中进行不同风速下的测压风洞试验,试验获得了阻力系数、升力系数、表面风压分布、风压相关性系数、斯托罗哈数等随雷诺数的变化特征,并将试验结果与以往结果进行比较。研究表明:升力系数... 为研究光滑圆柱的气动力系数和绕流特性,在均匀流中进行不同风速下的测压风洞试验,试验获得了阻力系数、升力系数、表面风压分布、风压相关性系数、斯托罗哈数等随雷诺数的变化特征,并将试验结果与以往结果进行比较。研究表明:升力系数的脉动值大于阻力系数的脉动值,说明涡脱造成的横风向激励比顺风向紊流激励剧烈;雷诺数位于临界区域时,圆柱表面风压分布呈现出对称-不对称-对称的变化过程,反映了由层流分离转化为湍流分离的全过程;在雷诺数为352000时呈现一侧为层流分离、另一侧为湍流分离的临界流态,风压呈现出左右不对称的单边泡形式;获得层流分离和湍流分离时的表面风压相关性分布特征,层流分离时圆柱同一侧的风压测点均呈较强的正相关,而湍流分离时在分离点前的区域相关性较强,分离点之后的区域相关性较弱;层流分离的升力系数谱有显著的峰值,表明尾流是规则的漩涡脱落,而湍流分离的升力系数谱没有明显峰值,表明尾流是随机的漩涡脱落。 展开更多
关键词 圆柱 风洞试验 气动力气数 风压分布 斯托罗哈
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Multi-SPline Technique for the Extraction of Drag Coeffidents from Radar Data 被引量:2
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作者 祁载康 《Journal of Beijing Institute of Technology》 EI CAS 1994年第1期42+33-42,共11页
In the preparation of firing tables, the determination of projectile drag coefficientsthrough firing test radar data reduction is very important. Many methods have been developed for this work but none of them appear ... In the preparation of firing tables, the determination of projectile drag coefficientsthrough firing test radar data reduction is very important. Many methods have been developed for this work but none of them appear to be satisfactory in one Way or another. Inthis paper a multi-spline model of drag coefficient (cd) curve is developed that can guaranteefirst derivative continuity of the cd curve and has good flexibility of fitting accurately to acd curve from subsonic up to supersonic range. Practical firing data reduction tests showboth fast convergence and accurate fitting results. Typical velocity fitting RMS errors are0.05-0.08 m/s. 展开更多
关键词 aerodynamic drag data reduction firing tables/aerodynarnic identification radar data reduction
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Wind tunnel test on aerodynamic effect of wind barriers on train-bridge system 被引量:17
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作者 GUO Wei Wei WANG Yu Jing +1 位作者 XIA He LU Shan 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2015年第2期219-225,共7页
To investigate the aerodynamic effect of wind barriers on a high-speed train-bridge system,a sectional model test was conducted in a closed-circuit-type wind tunnel.Several different cases,including with and without b... To investigate the aerodynamic effect of wind barriers on a high-speed train-bridge system,a sectional model test was conducted in a closed-circuit-type wind tunnel.Several different cases,including with and without barriers,with different barrier heights and porosity rates,and with different train arrangements on the bridge were taken into consideration;in addition,the aerodynamic coefficients of the train-bridge system were measured.It is found that the side force and rolling moment coefficients of the vehicle are efficiently reduced by a single-side wind barrier,but for the bridge deck these values are increased.The height and porosity rate of the barrier are two important factors that influence the windbreak effect.Train arrangement on the bridge will considerably influence the aerodynamic properties of the train-bridge system.The side force and rolling moment coefficients of the vehicle at the windward side are larger than at the leeward side. 展开更多
关键词 wind barrier train-bridge system wind tunnel aerodynamic coefficient windbreak effect
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Analysis of Particle Behavior in High-Velocity Oxy-Fuel Thermal Spraying Process 被引量:3
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作者 Hiroshi Katanoda Kazuyasu Matsuo 《Journal of Thermal Science》 SCIE EI CAS CSCD 2003年第3期279-282,共4页
This paper analyzes the behavior of coating particle as Well as the gas flow both of inside and outside the High-Velocity Oxy-Fuel (HVOF) thermal spraying gun by using quasi-one-dimensional analysis and numerical simu... This paper analyzes the behavior of coating particle as Well as the gas flow both of inside and outside the High-Velocity Oxy-Fuel (HVOF) thermal spraying gun by using quasi-one-dimensional analysis and numerical simulation. The HVOF gun in the present analysis is an axisymmetric convergent-divergent nozzle with the design Mach number of 2.0 followed by a straight passage called barrel. In the present analysis it is assumed that the influence of the particles injected in the gas flow is neglected, and the interaction between the particles is also neglected. The gas flow in the gun is assumed to be quasi-one-dimensional adiabatic flow. The velocity, temperature and density of gas in the jet discharged from the barrel exit are predicted by solving Navier-Stokes equations numerically. The particle equation of motion is numerically integrated using three-step Runge-Kutta method. The drag coefficient of the particle is calculated by linear interpolation of the experimental data obtained in the past. Particle mean temperature is calculated by using Ranz and Marchalls' correlation for spherical particles. From the present analysis, the distributions of velocity and temperature of the coating particles flying inside and outside the HVOF gun are predicted. 展开更多
关键词 supersonic nozzle supersonic jet thermal spraying gas-particle flow.
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Blade Parameterization and Aerodynamic Design Optimization for a 3D Transonic Compressor Rotor 被引量:4
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作者 Naixing Chen Hongwu Zhang Yanji Xu Weiguang Huang Institute of Engineering Thermophysics,Chinese Academy of Sciences,P.O.Box 2706,Beijing 100080,CHINA.E-mail:nxc@mail.etp.ac.cn Fax:+8610-62573335 《Journal of Thermal Science》 SCIE EI CAS CSCD 2007年第2期105-114,共10页
The present paper describes an optimization methodology for aerodynamic design of turbomachinery combined with a rapid 3D blade and grid generator (RAPID3DGRID), a N.S. solver, a blade parameterization method (BPM... The present paper describes an optimization methodology for aerodynamic design of turbomachinery combined with a rapid 3D blade and grid generator (RAPID3DGRID), a N.S. solver, a blade parameterization method (BPM), a gradient-based parameterization-analyzing method (GPAM), a response surface method (RSM) with zooming algorithm and a simple gradient method. By the use of blade parameterization method a transonic com- pressor rotor can be expressed by a set of polynomials, and then it enables us to transform coordinate-expressed blade data to parameter-expressed and then to reduce the number of parameters. With changing any one of the parameters and by applying grid generator and N.S. solver, we can obtain several groups of samples. Here only ten parameters were considered to search an optimized compressor rotor. As a result of optimization, the adiabatic efficiency was increased by 1.73%. 展开更多
关键词 Aerodynamic optimization blade optimization compressor bladings
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Investigation on high angle of attack characteristics of hypersonic space vehicle 被引量:19
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作者 HUANG Wei LI ShiBin +1 位作者 LIU Jun WANG ZhenGuo 《Science China(Technological Sciences)》 SCIE EI CAS 2012年第5期1437-1442,共6页
The high angle of attack characteristics play an important role in the aerodynamic performances of the hypersonic space vehicle. The three-dimensional Reynolds Averaged Navier-Stokes (RANS) equations and the two-equat... The high angle of attack characteristics play an important role in the aerodynamic performances of the hypersonic space vehicle. The three-dimensional Reynolds Averaged Navier-Stokes (RANS) equations and the two-equation RNG k-? turbulence model have been employed to investigate the influence of the high angle of attack on the lift-to-drag ratio and the flow field characteristics of the hypersonic space vehicle, and the contributions of each component to the aerodynamic forces of the vehicle have been discussed as well. At the same time, in order to validate the numerical method, the predicted results have been compared with the available experimental data of a hypersonic slender vehicle, and the grid independency has been analyzed. The obtained results show that the predicted lift-to-drag ratio and pitching moment coefficient show very good agreement with the experimental data in the open literature, and the grid system makes only a slight difference to the numerical results. There exists an optimal angle of attack for the aerodynamic performance of the hypersonic space vehicle, and its value is 20°. When the angle of attack is 20°, the high pressure does not leak from around the leading edge to the upper surface. With the further increasing of the angle of attack, the high pressure spreads from the wing tips to the central area of the vehicle, and overflows from the leading edge again. Further, the head plays an important role in the drag performance of the vehicle, and the lift percentage of the flaperon is larger than that of the rudderevator. This illustrates that the optimization of the flaperon configuration is a great work for the improvement of the aerodynamic performance of the hypersonic space vehicle, especially for a high lift-to-drag ratio. 展开更多
关键词 hypersonic space vehicle angle of attack characteristic lift-to-drag ratio numerical simulation
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Numerical investigation of radial inflow in the impeller rear cavity with and without baffle 被引量:6
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作者 LIU Guang DU Qiang +2 位作者 LIU Jun WANG Pei ZHU JunQiang 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2016年第3期456-467,共12页
In typical small engines, the cooling air for high pressure turbine (HPT) in a gas turbine engine is commonly bled off from the main flow at the tip of the centrifugal impeller. The pressurized air flow is drawn rad... In typical small engines, the cooling air for high pressure turbine (HPT) in a gas turbine engine is commonly bled off from the main flow at the tip of the centrifugal impeller. The pressurized air flow is drawn radially inwards through the impeller rear cavity. The centripetal air flow creates a strong vortex because of high inlet tangential velocity, which results in significant pressure losses. This not only restricts the mass flow rate, but also reduces the cooling air pressure for down-stream hot com- ponents. The present study is devoted to the numerical modeling of flow in an impeller rear cavity. The simulations are can'ied out with axisymmetric and 3-D sector models for various inlet swirl ratio ,80 (0-0.6), turbulent flow parameter 2-r (0.028-0,280) with and without baffle. The baffle is a thin plate attached to the stationary wall of the cavity, and is proved to be useful in re- ducing the pressure loss of centripetal flow in the impeller rear cavity in the current paper. Further flow details in impeller rear cavity with and without baffle are displayed using CFD techniques. The CFD results show that for any specified geometry, the outlet pressure coefficient of impeller rear cavity with or without baffle depends only on the inlet swirl ratio and turbulent flow parameter. Meanwhile, the outlet pressure coefficient of the cavity with baffle is indeed smaller than that of cavity without baffle, especially for the cases with high inlet swirl ratio. The suppression of the effect of centrifugal pumping and the mixing beween the main air which is downstream of the baffle and the recirculating flow of the vortex in the stationary cavity, which are caused by the use of baffle, are the underlying reasons that lead to the reduction of outlet pressure loss. 展开更多
关键词 impeller rear cavity de-swirling device BAFFLE Batchelor's Model Vortex Model
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Experimental and Analytical Analysis of Perforated Plate Aerodynamics
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作者 JürgenZierep RainerBohning Piotr Doerffer 《Journal of Thermal Science》 SCIE EI CAS CSCD 2003年第3期193-197,共5页
Perforated walls and transpiration flow play an important role in aerodynamics due to an increasing interest in application of flow control by means of blowing and/or suction. An experimental study was carried out whi... Perforated walls and transpiration flow play an important role in aerodynamics due to an increasing interest in application of flow control by means of blowing and/or suction. An experimental study was carried out which has led to the determination of a transpiration flow characteristics in the form of a simple formula that is very useful in modelling such flows. In connection to this relation a method of 'aerodynamic porosity' determination has been proposed which is much more reliable than geometric description of the porosity. A theoretical analysis of the flow through a perforation hole was also carried out. The flow was considered as compressible and viscous. The gasdynamic analysis led us to a very similar result to the relation obtained from the experiment. The adequacy of the theoretical result is discussed in respect to the experiment. 展开更多
关键词 transonic flow flow control transpiration flow perforated walls blowing and suction.
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