滨海火、核电厂温排放数值模拟研究进展

回顾近年来国内外滨海火、核电厂温排放数值模拟研究的进展,着重讨论现有温排放数值计算模型的发展以及存在的问题,主要包括温排放系统模式的选取和模型边界控制等。认为三维数值模型在一定程度上代表温排放数值模拟的发展方向,并应考虑斜压效应,且将水动力场与物质扩散场耦合求解。     

水利工程总溶解气体过饱和问题探讨

从对总溶解气体(TDG)过饱和概念的分析入手,阐述TDG过饱和的危害。通过对不同典型水体TDG饱和度的测量,表明泄流可以导致水体TDG含量增加甚至过饱和。在此基础上,采用试验研究的方法,探讨了TDG过饱和产生原因及其释放过程,表明水利工程泄流引起的TDG过饱和与泄流掺气、压力、紊动强度、水温等要素相关,并由此提出减缓水利工程TDG过饱和影响的建议。     

降低原水泵站运行成本的措施和可能效果

根据中国石化上海石化股份有限公司水务公司的生产实际情况,提出了使用调速水泵、合理控制管网压力、加大净水装置进水阀开启度等方法,并对可能效果进行了阐述。     

H-ADCP在流域引江济太工作中的实践

介绍了声学多普勒流速剖面仪（ADCP）的主要工作原理,总结了太湖流域引江济太调水工作的需要,以水平式ADCP（H-ADCP）系统在苏州望亭水文站中的应用为例,对比分析了2009年引水、排水期间H-ADCP和人工监测的数据,总结了H-ADCP的使用特点,比测分析结果说明ADCP测流数据合理准确,可为今后防汛、水资源管理信息化建设提供借鉴。     

黄河综合治理思考

黄河干支流已建的大量水库、电站、引水工程及大面积水土保持措施等,极大地改变了进入河道的水沙过程,引起了河道淤积萎缩。黄河宁蒙河段的治理主要是缩窄河槽、稳定流路,以提高中枯水河槽的挟沙能力,治河措施可兼顾保水作用。黄河龙潼河段的滩地堆沙和控导河势等综合治理须与古贤水库的规划设计紧密结合。黄河下游河道整治的基本要求是保持河道的纵向输沙平衡和平面上的河势稳定,根据水沙减少的情况修订规划,沿程整治河宽应随比降的减小而减小。干支流水库的调水调沙运用须与河道整治相互配合,才能更有效地发挥冲深河槽、稳定流路、输沙入海的作用。考虑到黄河流域下垫面的变化及水库的调节作用,建议利用过去的降水资料重新推算产生的径流,以修正水沙系列和洪水频率。     

黄河下游二级悬河段河势及漫滩模型分析

结合实体模型试验,在洪量和沙量不变的情况下,对概化处理后不同量级洪水条件下黄河下游二级悬河段的水沙过程进行了研究。结果表明:随着洪峰流量加大,进入滩区的水量也随之增大,其漫滩范围和落淤厚度有逐步增大的趋势,但漫滩洪水基本流路无大的变化;漫滩洪水的水流交换模式包括在三角形滩区内完成的淤滩刷槽交换模式和水流漫滩后通过较长距离条形滩区落淤后回归主槽的交换模式。     

水平旋流泄洪洞原型和模型的脉动压力特性对比与分析

依据公伯峡水平旋流泄洪洞原型观测和反演模型试验的成果,对这种新型水平旋流内消能泄洪洞在闸门启闭过程中的脉动压力特性进行了对比与分析。研究表明环形掺气坎上游竖井段、起旋室内及水平旋流洞内压力随时间变化趋势原型和模型的基本一致,符合重力相似准则;受缩尺效应的影响,原型和模型环形掺气坎的空腔长度不同,压力差异较大;起旋室内的压力变化可分为四个阶段;原、模型相应测点的水流的优势频率均属低频,远小于建筑物的固有频率。     

Delayed influence of dam storage and discharge on the determination of seasonal proliferations of Microcystis aeruginosa and Stephanodiscus hantzschii in a regulated river system of the lower Nakdong River (South Korea)

This study presents the relationship between the dam hydrology and phytoplankton proliferations in a regulated river system in East Asia. A long-term ecological study reveals that multi-purpose dam regulation on river flow in the Nakdong River (South Korea) affects proliferating patterns of phytoplankton, especially during summer (June-August) and winter (December-next February) as Microcystis aeruginosa and Stephanodiscus hantzschii, respectively, dominate each season by over 80%. Eutrophication was observed in the lower Nakdong River (South Korea) (mean+/-standard deviation: nitrate-N, 2.8+/-0.9 mg L(-1); phosphate-P, 40.3+/-31.3 microg L(-1); chlorophyll a, 45.2+/-84.9 microg L(-1); n=449), and the limnological characteristics responded to climatic variations such as monsoon and summer typhoons. The river basin experiences concentrated rainfall during the rainy season (June-September, over ca. 60% of total annual rainfall). Correlation and cross-correlation for time-delayed relationship revealed the hydrological environments (i.e., quantity of dam storage and discharge) had significantly negative relationship with the population dynamics of the two bloom-forming species for up to the next 2 years. S. hantzschii had clearer relationship with dam storage and discharge, which might be due to the seasonality exhibited by the species. The results support the necessity of "smart flow control" which may enable destruction of bloom formation by the two species with an adequate pulse of discharge generated by upstream dams in the far-east Asian river systems. This would increase the efficiency of water resource management system.     

Stainless steel membrane distributor-type dielectric barrier discharge plasma reactor for co-conversion of CH4/CO2

Flow arrangement in a dielectric barrier discharge (DBD) plasma reactor is key to affecting multi-component gas reactions. Herein, a stainless-steel membrane distributor-type DBD reactor was developed to allow the change of gas flow arrangements freely to understand their effect on plasma-assisted CH₄/CO₂ co-conversion to syngas. Variation of gas flow arrangements in the DBD reactor could regulate the reaction performance. Also, the inclusion of quartz wool in the DBD reactor could enhance the effect of gas flow arrangement compared to the plasma-alone DBD. Especially, the DBD reactor with CO₂ feed in the quartz wool-packed discharge zone and CH₄ distributed via the membrane exhibited good stability over 600 min on stream, with rather stable CO₂/CH₄ conversions of ~25%/20%, H₂/CO selectivities of ~50%/32%, H₂/CO molar ratio of 0.9–1.1, and energy efficiency of ~0.20 mmol·kJ⁻¹ based on the conversion of feed gases.     

正交混频式UHF局放在zynq7处理器上的实现

UHF(ulatr-high-frequency)局放传感设备中,混频在保留信号相位和幅度细节以及抗干扰方面比包络检波更有优势,但下变频后实信号直接混频必然引入3dB镜像频谱干扰。为了解决干扰问题,采用Xilinx公司主流的zynq7系列作为局放处理器,设计了一套正交混频型局放设备软硬件,提出了一种新型数字正交混频干扰...