低扬程贯流式泵站启动扬程的计算

将泵站从启动至正常运行分为4个阶段,进行泵站启动扬程的分析计算。指出影响泵站启动扬程的主要因素有泵站启动时进水池和出水池的水位差、出水流道工作闸门的开启速度、出水流道的结构布置。通过对贯流式泵站启动过程进行分析,运用水力学原理,就泵站启动扬程的主要影响因素提出一种分析计算方法。以淮安第三抽水泵站为例进行泵站启动扬程分析及计算,所得结果与泵站的实际启动运行情况基本吻合。     

ABAQUS软件在高进水塔动力分析中的应用

结合进水塔工程实例,利用大型商业有限元分析软件ABAQUS完成了进水塔的动力分析,着重研究了进水塔结构的自振特性和地震响应,验证了进水塔的强度要求,分析了进水塔结构的抗倾覆及抗滑移稳定性。在计算结果的基础上并提出了设计修改意见,为工程设计提供了依据。     

长江流域火电工业取用水定额多目标评价分析

针对单目标评价方法无法有效地评价火电工业取用水定额的优劣程度问题,基于投影寻踪法对长江流域火电工业取用水定额进行了多目标评价。首先分析了单目标评价方法对火电工业取用水定额的优劣评价结果;在此基础上开展了基于投影寻踪法的长江流域火电工业取用水定额的多目标评价研究。研究结果表明:长江下游地区的江苏华能太仓电厂三期工程的综合评分最高,而长江下游地区的江苏南通新区热电厂二期扩建工程的综合评分最低,评价结果相对合理客观。基于投影寻踪法的多目标评价相比单目标评价方法,可有效传递和辨识评价指标的信息价值,可给出长江流域火电工业取用水定额合理且客观的综合评价,推荐采用差评、合格、良好和优异4级综合指标划分法对火力发电厂取用水定额进行分级评价。     

山溪坝后式取水及明渠弯道除沙方式研究

随着我国水利水电工程建设的发展,水电站分布越来越集中于偏远山区,供水系统往往需自行建设。为了解决工程建设施工及生活用水问题,通常是将工程附近水源水质较好的山溪作为取水点,并经简单沉沙处理后投入使用。传统的坝前式山溪取水及大型沉沙池除沙普遍面临着汛期取水头部易被泥石流淤积、山溪内施工部位狭窄等问题,根据弯道环流原理,结合杨房沟水电站供水系统取水头部设计及运行使用经验,研究验证了坝后式取水代替传统的坝前式取水,以及明渠除沙代替大型沉沙池除沙方式的实际效果。实践表明,新的取水方式可以满足抗淤能力强、施工占地少,同时除沙能力理想的要求,可为今后类似情况下山溪取水及除沙方式的选择提供参考。     

Modelling Temperature,Body Size,Prey Density,and Stream Gradient Impacts on Longitudinal Patterns of Potential Production of Drift‐Feeding Trout

In this study, we modelled idealized stream reaches using empirical hydrodynamic and bioenergetic parameters to predict how rainbow trout production depends on physical and biological variations across a downstream gradient, and we compared these downstream effects in a low and high‐gradient stream reach. We found that longitudinal production potential (i.e. net rate of energetic intake per 100 m of stream length) generally increased with increasing stream size when stream gradient was low. This was not the case, however, for high‐gradient streams, wherein maximum longitudinal production potential was associated with middle or low stream size (Q_MAD = 2.5 to 25 m³ s^?1). Areal production potential (net rate of energetic intake per m² of wetted stream bed) reached a maximum at low stream size (Q_MAD = 2.5 m³ s^?1) with both high and low gradients. We also showed that high stream temperature and low drift density could potentially cause adult rainbow trout to be excluded from stream reaches with high flow. The models presented here have a stronger mechanistic basis for predicting fish production across heterogeneous stream environments and provide more nuanced predictions in response to variation in environmental features than their physical habitat‐based predecessors. Copyright © 2016 John Wiley & Sons, Ltd.     

PKPM在进水口结构计算中的应用

本文对进水口结构进行有效简化,采用PKPM系列软件中的PMCAD模块建立模型,考虑对结构最不利的荷载组合并输入计算荷载,利用PKPM系列软件中的SATWE模块进行进水口结构的内力及配筋计算,通过计算确定结构体型及配筋情况。     

Drinking behavior of lactating dairy cows and prediction of their water intake

The water intake of 41 lactating dairy cows managed according to current dairy farm practices was individually and continuously monitored to 1) investigate drinking behavior and 2) determine factors affecting water intake. The cows were housed in a free-stall barn and fed once daily with a corn silage and concentrate-based total mixed ration (48% dry matter content; 20.6 ± 3.3 kg/d of dry matter intake). Cows were milked twice daily, with a yield of 26.5 ± 5.9 kg/d. The daily free water intake (FWI) was 83.6 ± 17.1 L, achieved during 7.3 ± 2.8 drinking bouts. The drinking bout water intake was 12.9 ± 5.0 L. Almost three-fourths of the FWI occurred during working hours (0600 to 1900 h). Consumption peaks corresponded to feeding and milking times. More than one quarter of the daily FWI was met during the 2 h after each milking. About 75% of the present cows visited the watering point at least once during the 2 h after the evening milking. It is probable that drinking behavior evolved with lactation, but further studies are required to identify the relationship between lactation stage and drinking behavior. The most relevant factors affecting the daily FWI of lactating cows were best combined according to the following predictive equation: (R² = 0.45; n = 41 cows, n = 1,837): FWI, L/d = 1.53 × dry matter intake (kg/d) + 1.33 × milk yield (kg/d) + 0.89 × dry matter content (%) + 0.57 × minimum temperature (°C) - 0.30 × rainfall (mm/d) - 25.65. The results obtained using these equations were in agreement with the equations developed by other researchers.     

大型电站叠梁门分层取水进水口水力特性研究

电站进口前加设叠梁门后引起局部水流条件复杂,本文以模型试验和数值模拟为研究手段,系统阐述了叠梁门分层取水进口水流流态、门顶最小运行水深、水头损失和叠梁门反向附加水击压力等。研究表明,加设叠梁门后机组各栅孔进流较为均化,门井水面波动加大,主要引流区间在门顶以下10 m—门顶以上25 m水域,叠梁门门顶最小运行水深一般为15~30 m,进口段水头损失1.20~1.95 m(水头损失系数为0.45~1.15),较无叠梁门时增大1.11~1.63 m,对机组发电经济效益将产生一定影响,机组甩负荷对叠梁门下游面板产生的附加水击压力(2.9~3.0)×9.81 k Pa。     

取水工程附近河床冲淤规律数值模拟研究

取水口处的泥沙淤积问题关系到取水工程能否安全运行,从水流、河势角度论证了取水口布置的合理性,并减少取水对航道及防洪影响的必要性。以长江九江湖口水道某电厂取水口为例,采用平面二维水沙数学模型研究了取水口附近局部流态、河床冲淤、取水工程处悬沙含量等的变化规律,并对附近河床近期变化进行了预测。计算条件采用丰、中、枯典型年和典型系列年水沙条件,系列年考虑三峡工程和上游水库调度的影响。通过分析计算结果,选择了较优取水口方案,并推荐了适宜的取水口标高。研究结果表明,同一河段取水工程处河床冲淤规律受来水来沙条件和取水工程位置处的局部地形的共同影响。     

阀式自动控制闸在灌区现代化改造的优势探讨

灌区存在大量过流能力0.1m3/s以下的小型取水口,往往由于闸门设施简陋、管理粗放、缺少监控而产生严重的水资源浪费。农业水价综合改革要求计量用水到户,传统的小型取水口闸难以满足这一要求。本文基于江西锦北灌区小型取水口的管理现状和问题,讨论分析国内外现代化自动控制闸的适用性,提出自主研发阀式远程自动控制闸的方案。该闸型技术功能强而成本低、易于量产,可集成自动量水、远程控制与视频监控的一体化自动监控系统,便于安装与维护,运行管理效率高,在小型取水口大面积自动化改造方面优势明显,具有推广价值。