输水隧洞坡角对侧式进/出水口水力特性影响研究

抽水蓄能电站侧式进/出水口具有双向过流的特点,进/出水口自身体型参数对其水力特性具有很大的影响,但连接的输水隧洞布置型式也同样会影响进/出水口水力特性,若输水隧洞布置不恰当,将可能导致进/出水口出现不利的水力特性。利用RSM紊流模型,以某侧式进/出水口为研究对象,在进/出水口体型不变的前提下,研究出流工况不同隧洞坡角对进/出水口内部流态、拦污栅断面流速不均匀系数、水头损失系数及流量分配等水力特性的影响。结果表明,当隧洞坡角等于扩散段垂向扩散角时,进/出水口内部流态较好,反向流速区的沿程范围、拦污栅断面流速不均匀系数及水头损失系数均最小。因此,当进/出水口扩散段垂向扩散角不大且各隧洞坡角均满足地形、地质条件的情况下,隧洞坡角等于扩散段垂向扩散角时,可获得较优的水力特性。     

扩散段长度对侧式进/出水口水力特性的影响

以某上水库无调整段侧式进/出水口为研究对象,采用雷诺应力湍流模型探究了扩散段长度对进/出水口水力特性的影响规律,并从水力学的角度给出了扩散段长度建议值。结果表明：扩散段长度对侧式进/出水口水流运动存在显著影响,扩散段不宜过长或过短;对于进/出水口沿程流速分布,只有在抽水工况下扩散段长度才会对其产生影响,发电工况下基本不存在影响;对于水头损失、各孔口流量配比等其他水力指标,扩散段长度在双向过流时均会对其产生较大影响,随着扩散段长度的增加,各水力指标均先变好再变差;对于无调整段侧式进/出水口体型,当扩散段长度为隧洞直径的5.7～6.0倍时,各水力指标满足规范要求;当扩散段长度为隧洞直径的5.8倍时,进/出水口水力特性得到较大改善,且具有较好的水流流态。     

竖井式进/出水口布置形式对水流特性的影响

抽水蓄能电站竖井式进/出水口总体布置及边界复杂,水流条件易受体型轮廓影响。为研究进/出水口布置形式对水流的影响,在计算方法得到试验验证的基础上,采用基于VOF两相流的RNG k-ε湍流模型对工程中常见的布置形式进行三维数值模拟,分析了扩散段形式和分流孔数对水头损失、流速分布及流态的影响。研究成果对竖井式进/出水口的水力设计具有重要参考价值。     

惠州抽水蓄能电站下库进出水口水工模型试验研究

惠州抽水蓄能电站下库采用侧式进出水口，一期尾水隧洞与进出水口采用同轴线布置，二期尾水隧洞在平面上布置有一弯道。通过物理模型试验对下库进出水口水力特性进行研究，测试包括发电和抽水两种工况下进出水口流速分布、各通道流量分配、进出水口水头损失及入流漩涡等水力参数，通过多方案比较，解决了下库出水口流速分布不均和出流偏流等问题。     

抽水蓄能电站进/出水口体型优化数值模拟

利用三维紊流数学模型,对某抽水蓄能电站上水库进/出水口原方案及其优化方案抽水和发电工况进行数值模拟,分析了进/出水口段的水头损失、进/出水口段的流态和流速分布等。原方案在抽水工况下,存在扩散段及调整段顶盖板下部产生水流分离区、拦污栅断面有反向流速、各孔口流速不均匀系数偏大等不利水力学现象。考虑以上不利因素,需对原方案进行优化。优化方案计算结果表明,在扩散段和防涡梁段之间增加调整段、压低扩散段盖板扩散角以及增加扩散段长度等措施均能改善水流流态。     

某抽水蓄能电站进出水口体型优化的数值模拟

进出水口是水电站引水建筑物的重要组成部分,其水力特性对于降低水头损失至关重要。以厦门某抽水蓄能电站为例,在下库进出水口分别采用3种不同的分流墩体型,对不同工况下进出水口的流场进行了数值模拟,并分析了进出水口的水头损失、流速分布、流量及流态等,在此基础上提出了体型优化方案,有效地改善了进出水口的流态、降低了水头损失,可供类似工程设计人员参考。     

抽水蓄能电站侧式进/出水口隔墩布置对水力特性的影响

运用标准k-ε湍流模型和VOF两相流模型,对抽水蓄能电站侧式进/出水口、输水管道和部分上库进行了数值计算,分析了死水位条件下抽水和发电工况的进/出水口隔墩位置对进/出水口流速分布、流道分流系数、水头损失、墩头附近流速分布等水力特性的影响。结果表明:中隔墩后移对发电工况下各流道流速分布、分流系数、进/出口的水头损失几乎无影响;中隔墩后移可改善抽水工况下中隔墩两侧流道的过流流速均匀性和各流道流量分配的均匀性,降低进/出水口的水头损失,但中隔墩后移距离超过进/出水口扩散段起始断面宽度的0.3倍时,改善效果不明显;中隔墩后移进/出水口扩散段起始断面宽度的0.44～0.52倍,边隔墩后移进/出水口扩散段起始断面宽度的0.1倍,可实现墩头附近局部流速的相对均匀化;中隔墩后移扩散段起始断面宽度的0.5倍,边隔墩后移扩散段起始断面宽度的0.1倍,可实现抽水蓄能电站进/出水口水力特性的最优化目标。     

惠州抽水蓄能电站上库进出水口水力学模型试验

通过物理模型试验,测试了发电和抽水两种工况下惠州抽水蓄能电站上库进出水口的流速分布、各通道流量分配、进出水口水头损失及入流漩涡等水力参数,并对库盆流态进行了观测.试验结果表明,惠州抽水蓄能电站上库进出水口及引水隧洞的体型布置是基本合理的,可供其他类似工程初步设计时参考.     

佛子岭抽水蓄能电站上库进出水口水力实验研究

佛子岭抽水蓄能电站上库采用侧式进出水口,本文通过物理模型试验,测试了发电和抽水2种工况下佛子岭抽水蓄能电站上库进出水口的流速分布、各通道流量分配、进出水口水头损失及入流漩涡等水力参数,并对库盆流态进行了观测。试验结果表明,佛子岭抽水蓄能电站上库进出水口及引水隧洞的体型布置是基本合理的,可供其他类似相关工程初步设计时参考。     

利用多岛遗传算法的侧式进/出水口体型优化研究

水工建筑物体型优化一般通过物理模型试验或数值模拟对设定体型进行水力特性研究,针对不利的水力指标调整体型再进行研究,直至获得满意的较优体型,这是传统的做法。双向水流条件下的侧式进/出水口体型优化可视为多目标优化问题。本文将加权后的水头损失系数定为目标函数,以孔口断面流速不均匀系数和孔口间流量不均匀系数为约束条件,将多目标优化转化为单目标优化,利用多岛遗传算法进行进/出水口体型优化,可以获得最优体型。此外,参数化建模方法和基于CFD的响应面模型的应用,加快了建模与数值模拟速度,提高了优化效率。以某下水库侧式进/出水口为例,按照本文方法得到的推荐体型与原体型相比,进/出流的总水头损失系数降低3.35%,出流时流速不均匀系数减小14.50%,进/出流的流量不均匀系数均小于20%。该研究方法为水工建筑物体型优化提供了便捷的途径。     

台阶形陆架上孤立波传播的数值模拟

为了研究孤立波在带有陡升台地的陆架上的传播,用MAC方法求解了二维纳维尔-斯托克斯方程。本文在以下几点,改进了东京大学提出的修正的网格标记法:1.给出交错网格的新的标号系统;2.推导出自由表面上非规则星的新的压力迭代公式;3.对流函数、压力和速度使用了三值悬旗;4.把一维Burgers方程的部分守恒形式扩展用于二维N-S方程。这些使得程序更简单和精确。计算结果证卖,物理上很好地解释了孤立波的传播,入射波分成了反射波和透射波,然后开始分裂、破碎。 本文计算结果与线性波理论的结果很一致,但后者不能给出波运动的过程。     

Effect of a free surface on the formation of a wave bed of a channel flow

Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 5, pp. 50–52, May, 1989.     

Construction of a temporary protective embankment for eliminating a failure of a sewer inverted siphon

Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 9, pp. 16–19, September, 1991.     

新型隔壁式高压岔管结构研究

通过对新型分岔结构－隔壁式岔管的研究，认真分析其体形设计、力学试验和结构有限元计算成果，发现这种新型分岔管在布置、结构和水力学方面较普通的“Y”型和“卜、形岔管具有一定的优势，其分岔灵活，结构对称无缺省，承爱内、外水压力能力强，双向过流条件好，具有广阔的应用前景，比较适合于抽水蓄能电站中的高水头、大直径、深埋藏的岔管的运用要求。     

Non-spherical multi-oscillations of a bubble in a compressible liquid

Bubble dynamics are associated with wide and important applications in cavitation erosion in many industrial systems, medical ultrasonics and underwater explosions. Two recent developments to this classical problem are reviewed in this paper. Firstly, computational studies on the problem have commonly been based on an incompressible fluid model. However, a bubble usually undergoes significantly damped oscillation due to the compressible effects. We model this phenomenon using weakly compressible theory and a modified boundary integral method. This model considers the energy loss due to shock waves emitted at minimum bubble volumes. Secondly, the computational studies so far have largely been concerned with the first-cycle of oscillation. However, a bubble usually oscillates for a few cycles before it breaks into much smaller ones. We model both the first- and second-cycles of oscillationand predict damped oscillations. Our computations correlate well with the experimental data.     

Effects of spates of different magnitudes on a Phragmites japonica population on a sandbar of a frequently disturbed river

In flow‐regulated rivers, natural flow patterns and related sedimentation processes are disturbed, thus interrupting the magnitude and duration of spates. We hypothesized that this in turn might alter the impact of spates on plant communities inhabiting sandbars along the river channel. In order to test this hypothesis, the effects of spates of different magnitudes and durations on spatial variation and composition of a Phragmites japonica Steud. community on a sandbar during a 2‐year period were investigated. The flow variation of the river was continuously monitored, and the spates were categorized as small, medium or large, based on the magnitude (depth). Growth parameters (shoot length and shoot density), above‐ and belowground biomass of the plant community and the quantity of litter retained within selected quadrats, and ash‐free dry weight (AFDW) of the soil were observed at seven different locations: two each at the extreme upstream, middle and extreme downstream and one location in the downstream reaches of the sandbar. Our results showed that the aboveground biomass declined due to large‐scale spates; however, these spates triggered the formation of secondary shoots if sediments were accumulated as a result of the spates. Conversely, the aboveground biomass did not recover if the substrate was eroded. Accumulated litter beneath shoots was easily washed away due to spates, positively affecting shoot re‐growth. The effects of spates on the P. japonica plant community depended highly on the location of the plants on the sandbar and the magnitude and duration of the spates. The different erosion–sedimentation processes, depending on the local river channel morphology and spate types, significantly affected the growth and morphological characteristics of P. japonica population. Copyright © 2008 John Wiley & Sons, Ltd.