INVESTIGATION ON FLOW AND HEAT TRANSFER CHARACTERISTICS OF ANNULAR TWO-PHASE FLOW THROUGH THE VENTURITUBE

A model that incorporates the important phenomena in the annular gas-water flow through the Venturi tube is presented. A series of experiments are carried out to measure the flow and heat transfer characteristics in cold and hot conditions. Comparison between numerical and experimental results shows good agreement.     

土耳其的水电开发

在1960～2000年的40a间,土耳其共投资140亿美元用于水电开发,发电量年平均增长达10%。目前,土耳其年平均发电量为44035GW·h,仅相当于可开发总量的35%。在未来20a开发全部水电蕴藏量需要投资300亿美元,除了传统的筹资模式外,还需要新型的筹资模式。     

THE BUBMAC METHOD-A NUMERICAL METHOD BUBBLE DYNAMICS IN VORTEX CORE

This paper presents a numerical method called BUBMAC method,whichis based on the Marker And Cell(MAC) technique,to numerically simulate the problemof bubble dynamics in vortex core. With the incorporation of the azimuthal velocity intothe momentum equation, the model takes into account the complete interaction betweenthe bubble dynamics and the vortex flow field.The three momentum equations (N-Seqs.) are solved numerically by the finite-difference methed, and the motion of bubblesurface is described by tracing massless marker particles distributed only on the surface ofthe bubble. With some important medifications to the original MAC method, the numeri-cal accuracy of the method is conisderably increased. The validation of the proposed BUB-MAC method is checked by comparing the numerical results with some available analyticalsolutions in the cases of spherical bubble evolution and with numerical results in the casesof nonspherical collapse of bubble and bubble evolution in tip-vortex core. The compar-iso     

观测仪器的设计和安装

现在,观测大体积土体和岩石特性公认的工程方法是使用专门的野外观测仪器.土工工程师为评估工程安全并作出较经济合理的设计越来越重视使用观测仪器.一般仪器(它的应用及相关问题)的概念已在设计和施工中得到广泛的认可.在应用中,所获得的数据量迅速膨胀、硬件激增,加之工业自动化,使大部分专业技术人员的知识显得落后.由于水工工程师对一个成功的观测仪器程序的所有组成部分的理解有限,因此,这些专业技术人员通常需要在大学里进行正规培训.因此,这里所介绍的只是如何缩短现存的知识沟.本文重点集中     

水电站引水隧洞钢衬砌的压曲

采用数值模拟技术，对水电站引水隧洞的钢衬砌在外水压力作用下直到破坏的结构性能进行了研究。在数值模型中采用了真实条件来考虑逐渐的弹塑性压曲和与周围介质（混凝土和岩石）的接触条件的改变。研究了各种参数（如原始缺陷，加劲件类型和间距，钢材等级等等）的影响，同Jacobsen法作了详细比较，展示了该方法的有效性和限制。     

Empirical Analysis of Wealth Distribution Disparity of Chinese Residents and Its Changes

I. Introduction The widening wealth gap between the rich and the poor is currently becoming a focus of attention in China. It has two implications: excessive income gap and huge wealth disparity.A number of research papers have appeared on the subject of Chinese people’s income gap. However, there has been limited research on the distribution of people’s wealth. The already published research papers show especially a lack of empirical study of the dramatic changes in wealth distribution in…     

EVALUATION OF THE CUMULATIVE FORMATION OF HIGH-SPEED LIQUID JETS

1 .　INTRODUCTIONHigh speedliquidjetsareoftenseeninrainerosionsimulationofaircraftandmissiles ,JilbertandField[1] and jetcuttingofmaterials ,Kob ayashi[2 ] .Inthegenerationofjets ,itistechnicallyinterestingtoknowhowtooperatetheexperimen talfacilityattheoptimumconditiontoobtainthejetvelocitymostefficiently .ThisisdescribedbyShiandTakayama[3] ,ShiandItoh[4 ] ,ShiandIt oh[5] .Intheearlieststudyofa pulsedhigh speedliquidjet ,BowdenandBrunton[6 ] puttheliquidinanozzleandthenusedaslugimpact…     

对挪威高压混凝土封堵体的评论

早在1987年至1991年挪威就对高压封堵体的设计，施工和运行进行了研究。搜集和分析了30多个承受静水压力水头1000m以下的封堵体的详细资料，认为混凝土结构长度应取静水压力的2%～5%，而钢衬长度只能取压力水头的0.4%。1980年以来，各种资料证明在降低封堵体的透水性方面取得了技术进步。     

古加拉特4座坝使用保安闸门增加水库容量

最近用安装保安闸门的办法，增加了印度4座大坝的水库蓄量。这对增加农业产量起到了重要的作用，在这个国家的水资源缺乏地区，保证了可靠的供水，避免了修建新的水利工程的必要。