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偏工况下混流式水轮机压力脉动数值仿真及其改善措施研究 总被引:2,自引:1,他引:1
某电站混流式水轮机组在部分负荷时机组出力大幅摆动,真机试验结果显示尾水管涡带频率与发电机低频振荡频率接近,二者产生共振导致功率波动。本文采用CFD方法对该电站混流式水轮机进行了三维非定常数值模拟,对包括电站现用泄水锥、加长型泄水锥、在尾水管内安装阻尼栅、在尾水管内安装导流板等4种方案下水轮机内部非定常流动进行了仿真,对比分析了各种方案对尾水管内涡带形状和压力脉动的影响。计算结果表明:加长泄水锥能降低压力脉动的幅值,但不能改变压力脉动频率;相比于阻尼栅,在尾水管中安装导流板能更有效地改变尾水管水压力脉动的主频并减小压力脉动的幅值,且对水轮机效率的影响较小。 相似文献
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高水头平板闸门水力特性研究 总被引:3,自引:0,他引:3
结合三峡水电站排沙底孔工作平板闸门进行了高水头闸门水力特性试验研究 .内容包括在开启过程中 ,闸门底缘后漩涡水流剪切空化引起的闸门空蚀、振动及通气减蚀措施 ;闸门总体布置及最佳体型 ;闸门位置及底缘合理形式 ;加折流器及闸室区水流脉动特性 .提出了防止闸门空蚀及振动的具体措施 ,为高水头闸门结构设计提供科学依据 相似文献
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基于CFX求解器,针对具有通航功能的某小型闸站式侧向进水泵站进水池内的不良流态,开展了翼型导流板正交试验数值模拟研究.计算结果表明:无整流措施下,进水池流态紊乱,1~3号进水池存在大尺度的回旋区,流速分布不均匀,轴向流速分布均匀度仅为76.84%;在离进水池进口1 D处设置4个仰角为25°的翼型导流板,进水池大尺度回旋... 相似文献
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Du Guang-sheng School of Energy Power Engineering Shandong University Jinan ChinaLei Li Shanghai Institute of Applied Mathematics Mechanics Shanghai University Shanghai ChinaZhou Lian-di China Ship Scientific Research Center Wuxi China 《水动力学研究与进展(B辑)》2003,15(4)
1 . INTRODUCTIONVan bodytruckshavesbeeninincreasinglywideuseinrecentyearsduetomanyadvantagessuchaspreventingrain ,sunshineanddust ,loadingorunloadingconvenientlyandsafety .AlongwiththerapiddevelopmentoffreewayinChina ,theaveragespeedofautomobileshasbeen greatlyraised .Theaerodynamicshapeofthevan bodytruckisnotsogoodowingtoitslargeaerodynamicdragcausedbyitsstructure ,whichisproportionaltothespeedofthetruck ,andincreasesnotablyinthefractionofthetotaldragcomparedwiththeconventionaltrucks .E… 相似文献
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Many river rehabilitation projects to enhance the aquatic habitat focus on the creation of pool and riffle habitat by the implementation of flow deflectors, with various degrees of successes and failures. A more comprehensive understanding of the complex three‐dimensional flow dynamics that induces scour around instream structures is required for a more effective design. The objective of this study is to examine the three‐dimensional mean and turbulent flow characteristics around paired flow deflectors for various types of deflector design in a laboratory flume. Three deflector angles (45°, 90° and 135°) and two deflector heights (with flow under and over the deflector height) were tested over a smooth (plexiglas) bed and a sand bed. Three‐dimensional velocity measurements were taken with an acoustic Doppler velocimeter at several planform positions at two heights above the bed. Results show that the 90° deflectors create the most important disturbance in the mean flow field, in turbulence intensity and bed shear stress. There is, however, a marked difference in the spatial distribution of the mean and turbulent parameters over a mobile bed and over a smooth, fixed bed. This stresses the importance of understanding the feedback between bed topography and flow dynamics and limits the applicability of conclusions drawn from plane bed experiments to natural rivers. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
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以湖南阳明山水电站及广西桂林银河水电站等电站的设计为例,论述了冲击式水轮发电机组在设计、实际运行过程中经常出现的一些问题,分析了该类型机组出现这些问题的原因,并提出了解决措施。 相似文献
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Ph.D.Candidate: Du Guang- sheng Institute of Energy Power Engineering Shandong University Jinan ChinaSupervisor: Zhou Lian-di 《水动力学研究与进展(B辑)》2002,14(2)
BRIEFINTRODUCTIONOFTHEPAPER : Thevan bodytruckisabluntbodywithirregularshape .Thispaperfirstlydealtwithmanyproblemsinexperimentalt 相似文献
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缓坡条件下掺气减蚀设施的体型研究 总被引:7,自引:0,他引:7
结合小湾泄洪洞掺气减蚀设施优化研究,提出了“当量坎高”的概念与凹型掺气坎的布置构想,在相同“当量坎高”的前提下,通过1:60水工模型试验,对平面凹型、平面凸型、平面梯形、U型坎,以及直线型挑坎等掺气坎体型进行了对比试验研究,从掺气浓度、空腔特性及通气量等指标看,凹型掺气坎是一种较优的布置形式.从物理机制上看,平面凹型掺气坎因空腔内水气交界面积大,对提高空腔内的总通气量、改善掺气条件有利;另外,相对于其他异型掺气坎而言,凹形掺气坎在两侧边墙处空腔更为完整一些,这对提高边壁角隅区域水流的掺气能力,增进边墙的抗空蚀效果也有一定的助益. 相似文献