碾压混凝土坝应力场有限元及施工仿真分析

采用三维有限元法对某碾压混凝土坝(RCC)在施工导流期的应力场进行分析,着重校核了顶部未到设计龄期的碾压混凝土和大型导流底孔周边的应力分布;并初步探讨了在多因素影响情况下,从开始施工到蓄水运行的坝体温度场、应力场的全过程仿真分析方法。     

Effect of Channel Changes in the St. Clair River During the Present Century

Periodic man-made changes in the outlet of Lake Huron through the St. Clair River date back to the middle of the last century. These artificial channel changes have been well documented during the present century. They consist of dredging for commercial gravel removal in the upper river during 1908–25 and uncompensated navigation improvements for the 7.6-m (25-ft) and 8.2-m (27-ft) projects completed in 1933 and 1962, respectively. The total effect of these changes on the levels of Lakes Michigan and Huron (hydraulically one lake) and on the upper St. Clair River profile was determined with dynamic flow models. The ultimate effect of the above dredging was a permanent lowering of the Lake Michigan-Huron levels 0.27 m (0.89 ft), which represents a tremendous loss of freshwater resource [32 km³ (7.7 mi³)].     

龙滩尾水出口枯期围堰设计与施工

介绍龙滩水电站尾水出口工程枯期围堰的设计参数及计算过程,结合施工过程中的实际情况,总结得出土石子围堰的闭气方法和浆砌石主围堰堰体防渗的应注意几个问题。     

炭粒床高效工业除尘装置的设计与开发

The new dust removal technical route using the carbon-granular bed filter,packed of carbon particles with appropriate grade derive from an online-process vibration sieve,to replace the traditional baggy filter had been developed successfully for capturing the micro-carbon dusts produced from pulverization of petroleum coke,and the green close loop of carbon materials is thus completed in the combined pulverizing and classifying system and pulverized carbon dust removal process.The high dust removal efficiency greater than 99%,low outlet dust concentration less than 100 mg.m-3,low pressure drop through dust filtration chamber less than 980 Pa,simple and easy design,and flexible and stable operation were achieved also with the carbon-granular bed filter in both bench and industrial scale operations.     

Side-outlet spouted bed with draft tube: Effect of varying the position of the outlet

The vector form of the Ergun equation was used to numerically predict gas phase streamlines, residence time distributions, chemical conversions and pressure drops in the annulus of a side-outlet spouted bed with an internal draft tube. By varying the position of the side-outlet, it was demonstrated that there exists an optimum location for this outlet at which conversion is a maximum and which shows a greatly improved gas phase residence time distribution in the annulus compared with a conventional spouted bed unit.     

新形势下做好长江入河排污口管理的思考

从长江流域水质现状、入河污染物排放基本情况及国家关于长江经济带绿色发展的总体要求出发,分析了长江水资源保护面临的形势;从长江入河排污口区划、审批、监管及基础工作方面,对入河排污口管理现状进行了简要总结,并对存在的问题进行了梳理。基于长江入河排污口管理面临的形势,提出了长江委强化长江入河排污口管理的总体思路和重点工作,可以为新形势下做好长江入河排污口管理提供参考。     

某抽水蓄能电站下库进出水口水沙运动特性试验研究

利用河工模型对某抽水蓄能电站下库区进行了特征洪水过程及电站运行的联合模拟试验。试验表明在输沙槽与拦沙潜堰共同作用下,电站进出水口的含沙量得到有效控制。在来水含沙量低于3kg/m3时,进出水口含沙量都满足电站运行要求,但是在含沙量较高的洪水期,底部浑水会逆行至电站进出水口附近,导致过机含沙量较高,因此提出了增设非封闭式拦沙潜坝的修改方案。修改方案改善了进出水口前的水流结构,起到了良好的拦沙截淤作用,进出水口前含沙量及泥沙淤积大幅减少,蓄能期过机含沙量降低13%~22%。在含沙量较大的洪水期,电站不宜抽水运用,但适时采用发电运行有助于减轻下库进出水口前的泥沙淤积。     

煤质劣化对锅炉热量分配影响的机理分析

受能源供应紧张影响电厂经常燃用劣质煤,其主要特点是灰分、水分大而发热量低,以此特征为基础建立一种煤质劣化模型。利用炉内传热相似理论求解方法,以一300 MW燃煤机组炉膛结构设计为例分析了不同劣化程度的煤质对锅炉主要设计参数造成的影响。计算结果表明:随煤中水分和灰分增加单位辐射热量降低,并且水分的影响大于灰分;随煤灰分增加单位辐射热量与单位对流热量之比升高,但随水分增加而降低。高负荷时,随煤中水分和灰分增加炉膛出口烟温略微降低;低负荷时,随煤中灰分增加炉膛出口烟温略微降低,而随煤中水分增加略微升高。     

堰塞体溃决离心模型试验供水系统关键技术研究

堰塞体溃决洪水洪峰流量及洪水时程曲线特征的预测是堰塞湖应急抢险及下游风险控制方案制订的重要依据。堰塞体溃决的离心模型试验,在研究堰塞体溃决机理、溃决过程及溃决洪水的历时曲线特征方面独具优势,但离心模型试验供水系统的设计,涉及到从外部静止状态到高速旋转状态的模型中连续供水,同时还要保证堰塞体溃决过程中上游水位为设定的常水头,是堰塞体溃决离心模型试验中的关键性的一大难题。本文围绕以上难题,设计了一种环形水箱以解决从静态到动态模型的连续供水问题,通过理论分析,确定了环形水箱中可提前注入的最大水量。另外在试验箱设置了竖井式溢流口,可以排出高出设定常水头的水体,保证了上游水位的稳定。通过以上设计有效地解决了供水系统中的关键难题,并在后续堰塞体溃决离心模型试验中得到了验证。     

三河口水利枢纽泄洪消能工体型优化试验研究

通过水力学模型对三河口水利枢纽泄洪消能工体型进行了试验研究。结果表明:两底孔出口采用矩形不对称宽尾墩形成的窄缝体型,三表孔采用左、右表孔差动式齿坎与中表孔舌型鼻坎组合的优化方案具有表孔、底孔出口水舌上下分层、前后拉开、横向扩散的特点,从而改善了水垫塘内的水流流态,提高了消能效率,水垫塘底板所受动水冲击压力及脉动压力达到了设计要求。