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Chinese Physics B 2010年第10期19卷 428-435页

作者：姜晓庶闫映策原世民米庶牛振国梁九卿 Department of Physics Shanxi University

We have performed a first-principles investigation for the family of compounds ZnGa2X4 （X = S, Se, Te）. The properties of two possible structures, defect chalcopyrite and defect famatinite are both calculated. We reveal that ZnGa2S4 and ZnGa2Se4 have direct band gaps, while ZnGa2Te4 has an indirect band gap. The local density approximation band gaps are found to be very different in two structures, while the lattice parameters and bulk moduli are similar. We extend Cohen＇s empirical formula for zinc-blende compounds to this family of compounds. The pressure coefficients are calculated and metallization pressures are discussed. We find that agi remains fairly constant when thegroup-V/element X is varied in ZnGa2X4（Ⅱ-Ⅲ2-Ⅵ4）.

关键词： electronic structure bulk modulus pressure coefficient

A HOMOGENOUS-EQUILIBRIUM-MODEL BASED NUMERICAL CODE FOR CAVITATION FLOWS AND EVALUATION BY COMPUTATION CASES

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Journal of Hydrodynamics 2008年第2期20卷 186-194页

作者： CHEN Ying LU Chuan-jing Department of Engineering Mechanics Shanghai Jiaotong University Shanghai 200240 China

A computer code, ELANEX, including several Homogenous-Equilibrium-Model （HEM） type cavitation models, were developed, to numerically simulate natural cavitation phenomena. The effectiveness of the code was checked by cavitation flows around the disk and cylinder body for a wide range of different cavitation numbers. Cavity profiles were compared with the analytic solution of disk and empirical formulae fitted from the experiment data, and contrast between different cavitation models were fulfilled as well. The cavity length and maximal cavity diameter were found to agree well with the analytic solutions, and detailed cavity profiles were in accordance with the experimental formula. Comparison with the hemisphere headed cylinder body presented a good agreement of the pressure coefficient with the experiment data. Reasonable drag-force coefficient variation and drag-force reduction effect were obtained.

关键词： cavitation numerical code disk hemisphere cavity profile pressure coefficient

Prediction of Dynamic and Aerodynamic Characteristics of the Centrifugal Fan with Forward Curved Blades

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Journal of Thermal Science 2013年第6期22卷 517-521页

作者： Jií Polansky László Kalmár Roman Gápár Univerzitní 8 306 14 PlzeňCzech Republic Miskolc-Egyetemváros MiskolcHungary

The main aim of this paper is determine the centrifugal fan with forward curved blades aerodynamic characteristics based on numerical modeling. Three variants of geometry were investigated. The first, basic "A" variant contains 12 blades. The geometry of second "B" variant contains 12 blades and 12 semi-blades with optimal length[1]. The third, control variant "C" contains 24 blades without semi-blades. Numerical calculations were performed by CFD Ansys. Another aim of this paper is to compare results of the numerical simulation with results of approximate numerical procedure. Applied approximate numerical procedure [2] is designated to determine characteristics of the turbulent flow in the bladed space of a centrifugal-flow fan impeller. This numerical method is an extension of the hydro-dynamical cascade theory for incompressible and inviscid fluid flow. Paper also partially compares results from the numerical simulation and results from the experimental investigation. Acoustic phenomena observed during experiment, during numerical simulation manifested as deterioration of the calculation stability, residuals oscillation and thus also as a flow field oscillation. pressure pulsations are evaluated by using frequency analysis for each variant and working condition.

关键词： Centrifugal Fan CFD pressure coefficient Flow coefficient

The Effect of Non-equilibrium Condensation on the Drag coefficient in a Transonic Airfoil Flow

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Journal of Thermal Science 2012年第6期21卷 518-524页

作者： I.W.Kim M.M.A.Alam S.J.Lee Y.D.Kwon S.B.Kwon School of Mechanical Engineering Kyungpook Nat.Uni.1370Sankyuk-dongDaegu 702-701Korea Dept.of Advanced & Control Eng.Saga Uni.Japan

In this study, a transonic flow past NACA0012 profile at angle of attack α=0^0 whose aspect ratio AR is 1.0 with non-equilibrium condensation is analyzed by numerical analysis using a TVD scheme and is investigated using an intermittent indraft type supersonic wind tunnel. Transonic flows of 0.78-0.90 in free stream Mach number with the variations of the stagnation relative humidity（φ0） are tested. For the same free stream Mach number, the increase in φ0 causes decrease in the drag coefficient of profile which is composed of the drag components of form, viscous and wave. In the case of the same Moo and To, for more than φ0=30%, despite the irreversibility of process in non-equilibrium condensation, the drag by shock wave decreases considerably with the increase of φ0. On the other hand, it shows that the effect of condensation on the drag coefficients of form and viscous is negligible. As an example, the decreasing rate in the drag coefficient of profile caused by the influence of non-equilibrium condensation for the case of M∞=0.9 and φ0 =50% amounts to 34%. Also, it were turned out that the size of supersonic bubble （that is, the maximum height of supersonic zone） and the deviation of pressure coefficient from the value for M=1 decrease with the increase of φ0 for the same M∞.

关键词： Non-equilibrium condensation Transonic Moist air Drag coefficient pressure coefficient

Structural optimization strategy of pipe isolation tool by dynamic plugging process analysis

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Petroleum Science 2021年第6期18卷 1829-1839页

作者： Ting-Ting Wu Hong Zhao Bo-Xuan Gao Fan-Bo Meng College of Mechanical and Transportation Engineering China University of PetroleumBeijing102249China

During the pipeline plugging process,both the pipeline and the pipe isolation tool(PIT)will be greatly damaged,due to the violent vibration of the flow *** this study,it was proposed for the first time to reduce the vibration of the flow field during the plugging process by optimizing the surface structure of the ***,the central composite design(CCD)was used to obtain the optimization schemes,and the drag coefficient and pressure coefficient were proposed to evaluate the degree of flow field ***,a series of computational fluid dynamics(CFD)simulations were performed to obtain the drag coefficient and pressure coefficient during dynamic *** the mathematical model of drag coefficient and pressure coefficient with the surface structure of the PIT were established ***,a modified particle swarm optimization(PSO)was applied to predict the optimal value of the surface structure of the ***,an experimental rig was built to verify the effectiveness of the *** results showed that the improved method could reduce the flow field vibration by 49.56%.This study provides a reference for the design of the PIT surface structure for flow field vibration technology.

关键词： Pipe isolation tool Dynamic analysis Drag coefficient pressure coefficient Modified particle swarm optimization algorithm

Acoustic Prediction and Risk Evaluation of Shallow Gas in Deep-Water Areas

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Journal of Ocean University of China 2022年第5期21卷 1147-1153页

作者： YANG Jin WU Shiguo TONG Gang WANG Huanhuan GUO Yongbin ZHANG Weiguo ZHAO Shaowei SONG Yu YIN Qishuai XU Fei College of Safety and Ocean Engineering China University of Petroleum(BeijingBeijing 102249China Institute of Deep-Sea Science and Engineering Chinese Academy of SciencesSanya 572000China CNOOC Research Institute Beijing 100028China CNOOC China Limited Shenzhen Branch Shenzhen 518000China CNOOC China Limited Beijing 100010China

Shallow gas is a potential risk in deep-water drilling that must not be ignored,as it may cause major safety problems,such as well kicks and ***,the pre-drilling prediction of shallow gas is *** this reason,this paper conducted deep-water shallow gas acoustic simulation experiments based on the characteristics of deep-water shallow soil properties and the theory of sound wave speed *** results indicate that the propagation speed of sound waves in shallow gas increases with an in-crease in pressure and decreases with increasing *** and sound wave speed are basically functions of the power *** with the theory of sound wave propagation in a saturated medium,this paper establishes a multivariate functional relationship between sound wave speed and formation pressure and *** numerical simulation method is adopted to simulate shal-low gas eruptions under different pressure *** gas pressure coefficients that fall within the ranges of 1.0-1.1,1.1-1.2,and exceeding 1.2 are defined as low-,medium-,and high-risk,respectively,based on actual *** risk assessment me-thod has been successfully applied to more than 20 deep-water wells in the South China Sea,with a prediction accuracy of over 90%.

关键词： shallow gas acoustic simulation experiment sound wave speed pressure coefficient risk evaluation

pressure distributions on prism-shaped buildings in experimentally simulated downburst

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Science China(Technological Sciences) 2014年第10期57卷 2070-2081页

作者： LI HongHai OU JinPing School of Civil Engineering Harbin Institute of Technology

Wind loading is one of the most significant factors in civil engineering that influences the structural design *** this paper,a group of manufacturing equipments for downburst simulation based on impinging jet model was developed for investigating the wind loads on structures:including the centrifugal air bellows to generate airflow,a movable platform to realize multiple locations of the building and a freely rotatable turntable to implement alterable building *** of transducers were used to measure the wind action on all surfaces of the *** pressure coefficients calculated from the observed data were utilized to evaluate the downburst wind *** distributions on three prism-shaped building models with different placements and angles were investigated to obtain the maximum wind action and mean pressure *** results showed that the maximum pressure coefficient would reach 1.0 on the top surface if the downburst just broke out over the *** that the building was in the developing field of the downburst,the top and the front surfaces would be under high wind pressure and only the back surface would endure wind *** the downdraft happens away from the prismatic building,all surfaces,except the front surface,would subject to suction with different *** was also found that the pressure coefficient on the right surface would get its negative peak at first and then go straight up to 0.6 as the angle changed from 0°to 45°and the wind pressure on the front surface would decrease slightly through the whole *** assertive results provide elemental data for structural wind-resistant design in civil engineering for the downburst-prone areas.

关键词： wind loading downburst pressure coefficient building structure impinging jet model

Study of the Flow Mechanism of Wind Turbine Blades in the Yawed Condition

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Energy Engineering 2022年第4期119卷 1379-1392页

作者： Shuang Zhao Xijun Li Jianwen Wang College of Energy and Power Engineering Inner Mongolia University of TechnologyHohhot010051China Key Laboratory ofWind Energy and Solar Energy Technology Ministry of EducationHohhot010051China Key Laboratory of Wind and Solar Energy Utilization andOptimization in Inner Mongolia Autonomous Region Hohhot010051China Beijing Jingneng International Integrated Smart Energy Co. Ltd.Beijing100073China

The computational fluid dynamics method was used to simulate the flow field around a wind turbine at the yaw angles of 0°,15°,30°,and 45°.The angle of attack and the relative velocity of the spanwise sections of the blade were extracted with the reference points *** analyzing the pressure distribution and the flow characteristics of the blade surface,the flow mechanism of the blade surface in the yawed condition was *** results showed that the variations of the angle of attack and the relative velocity were related to the azimuth angle and the radius in the yawed *** larger the yaw angle was,the larger the variation *** pressure distribution in the spanwise sections was affected by both the angle of attack and the relative *** angle of attack was more influential than the relative *** the same yaw angle,when the angle of attack decreased,the c_(p)∼x/c curve shrunk inward and the lift force *** larger the yaw angle was,the more obvious the shrink *** effect of the yaw on the blade root region was higher than its effect on the blade tip region.

关键词： Flow characteristic angle of attack relative velocity pressure coefficient flow separation

Wind tunnel test on low‑rise buildings influenced by hillside height in typical mountain terrain

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Advances in Aerodynamics 2024年第1期6卷 402-420页

作者： Min Zhong Minghui Lin Zhanxue Zhou Zhengnong Li Junyu Lu Fen Xu Jiangsu Open University Nanjing 210000China Hebei University of Architecture Zhangjiakou 075132China Hunan University Changsha 410082China

Hills and mountain fields have a high proportion in coastal areas around the *** in China,lots of low-rise buildings are in complex mountain ***-pared with the flat topography under typhoons,due to the change caused by com-plex topography,the damage ratio of low-rise buildings is much *** paper investigates the wind pressure distribution in three different configurations of typi-cal mountain terrain on low-rise buildings in coastal areas by wind tunnel *** the same time,the results are compared with the wind pressure distribution of low-rise buildings without surrounding *** variation of the average pressure coef-ficient and shape coefficient with the change of hillside height under a wind attack angle of 0°and the trends of average wind pressure coefficients of a low-rise building under wind attack angles of 0°–90°are *** results show that the distribution of pressure in low buildings is significantly affected by the height of the *** the hillside height is half of the scale physical model,the influence coefficient from the mountain to each surface of the whole building is within 50%.When the hill-side height is four times that of the model,the influence factor from the mountain to each surface of the whole building is obvious and is most significantly influenced by the leeward *** mean design criteria of the low-rise building,such as wind-ward midline,leeward roof,and windward roof in these three typical mountain terrains,should be designed for their higher absolute value of the average pressure *** mean pressure coefficient under different wind angles and mountain environ-ments has a significant *** most unfavorable wind angle of wind load calculations should be considered when designing low-rise buildings.

关键词： Low-rise buildings Mountain terrain Wind load Wind tunnel experiment pressure coefficient

Comparison and harmonization of building wind loading codes among the Asia-Pacific Economies

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Frontiers of Structural and Civil Engineering 2013年第4期7卷 402-410页

作者： Yaojun GE Shuyang CAO Xinyang JIN State Key Laboratory for Disaster Reduction in Civil Engineering Tongji UniversityShanghai 200092China China Academy of Building Research Beijing 100013China

This paper reviews wind loading codes and standards in the Asia-Pacific Region,in particular in the 15 countries and areas.A general description of wind loading model is given as a famous wind loading chain described by four variables including velocity pressure,exposure factor,pressure coefficient,and gust response *** the APEC-WW Workshops and the extensive calculations for three examples of low,medium and high rise buildings,these four important variables of wind loads are evaluated and compared with statistical parameters,mean values and coefficients of *** main results of the comparison show some differences among the 15 economies,and the reasons and further incorporation are discussed and suggested.

关键词： wind loading codification velocity pressure exposure factor pressure coefficient gust response factor