这种振动主要是由尾水管中的旋涡带所致。
This is caused principally by the vortex core of whirling water in the draft tube.
增大调压室面积会明显改变尾水管最小压力值。
Enlarging the sectional area of surge tank obviously changes minimum pressure in draft tube.
如改变尾水管形状，可以消除涡带压力脉动，减小机组振动。
If the shape of tailrace pipe is changed, the pressure pulse can be removed so that the vibration of generating unit can be reduced.
本文还根据计算结果分析了尾水管内非定常涡带产生和传播的原理。
In the meantime, the helical vortex rope in draft tube is analyzed by t...
结合伊朗塔里干电站项目，将普通尾水管改型设计成窄高型尾水管。
Combined with the Taligan Powerplant Project of Ir an, common draft tube is remodeled to high-and-narrow type draft tube.
水轮机在偏离最优工况运行时，水流的环量会使尾水管中心产生低压并形成涡带。
In case of the turbine is operated departing the optimum condition, the low presure and the vortex band will be established in the draft tube centre by the flow circulation.
混流和轴流定浆式水轮机在部分负荷下运行时，尾水管中常出现较为强烈的振动。
There iss strong vibration in the draft tube of a Francis turbine or axial flow fixed blade propeller hydraulic turbine when the turbine is running on part loading.
详细分析了尾水管进口截面的压力脉动的幅值和相位，并对尾水管内的流动做了分析。
Amplitude and phase of pressure fluctuation at the inlet of draft tube as well as the inner flow in draft tube are analyzed in detail.
通过与模型试验结果进行比较可以看出，本计算能够比较准确地预测尾水管内的压力脉动。
The comparison between the calculation results and experimental data indicates that the calculation in this paper can medict the pressure fluctuation in draft tube very well.
数值模拟得到的尾水管中压力脉动的频率，与湖北中试所在隔河岩进行测试的结果基本一致。
The pressure fluctuation in the draft tube is obtained. The calculated pressure fluctuation frequency agrees with the test data.
此外，发现开度较小时尾水管内存在明显的涡带和回流涡结构，容易导致机组运行的不稳定；
Besides, a notable vortex rope and a reverse flow structure exist in the draft tube in smaller wicket gate openings, which can easily lead to the instability in operation of the pump-turbine.
计算获得了分离流、二次流和多尺度旋涡结构，表明SST模型能很好地预测尾水管内的湍流流动。
Finally, separation flow, secondary flow and multi-scale eddy structure are simulated, it indicates that SST model can give a good prediction of turbulence in the draft tube.
当下游水位最低时，尾水管进口真空变化最明显，随着下游水位的上升，尾水管进口真空度逐渐改善。
The vacuum degree at tailrace adit varies most significantly at the lowest downstream water level and improves gradually along with the rising of downstream water level.
总体来说，尾水管进口断面水压在甩负荷过程中是升高的，而导叶后断面的水压随导叶关闭急剧下降。
The water pressure at the entrance of draft tube rises in the process of load rejection, but the pressure behind the guide vanes drops rapidly following the closing of operation.
许多研究成果表明，影响水轮机水力稳定性有多种因素，其中一个重要因素是尾水管内水流的压力脉动。
Many study results showed that pressure fluctuation in draft tubes is one of the most important factors that affects the stability of turbines.
河床式水电站水头比较低，而单机流量通常较大，这样水电站厂房的进水口、蜗壳和尾水管等尺寸较大。
In general, the head pressure of power station in river channel is lower comparatively, but the unit discharge is always greater, in this way, the dimension of the hydropower house is usually larger.
本文通过尾水管内流动的模拟，导出了由尾水涡带所引起的周期性振动的振动频率和脉动压力的计算公式。
This paper gives the flow simulation of hydraulic turbine draft tubes. Then, the calculation formula of the frequency and force of vibration of the draft tube are derived.
求解过程中各参数的设置合理，可以较好地反映尾水管中的主要流动现象，同时也说明了流场计算结果的正确性。
Defined parameters were appropriate, which can reflect main flow in draft tube. It also instructed that the calculation was correct.
基于有限元法，分析了两个尾水管在各自最大内水压力条件下外围混凝土的受力，得到各自的应力变化规律和特点。
Stress of surrounding concrete of each draft tube is analysed by the finite-element method under condition of the highest hydraulic pressure and the variable regularity of stress is obtained.
对水轮机模型，测取了从直锥段进口至尾水管出口8个截面共26个测点在6个稳定运行工况下的水压力脉动数据。
In the experimental study, the pressure surge data are acquired at 26 points from the taper pipe intake to the draft tube exit distributing at 8 sections under 6 stable operating conditions.
由于各种原因产生的高频和低频的压力脉动会使尾水管内部产生严重的空蚀破坏或者诱发水轮机叶片产生振动等问题。
Pressure fluctuations with high or low frequency can lead to acute cavitation damage in draft tubes or vibration of the vane of turbine.
通过水压力脉动数据的FFT频谱分析，研究了直锥段和尾水管内部在不同位置不同工况下的压力脉动在时域及频域上的变化规律。
With the FFT analysis it is analyzed that the pressure surge changing laws in the taper pipe and draft tube in time domain and frequency domain.
本文介绍有关推广应用12a窄高型尾水管的试验研究成果，给出了应用12a肘管和确定具有该肘管的尾水管主要几何参数所必需的一些数据。
Some data which are necessary for using elbow 12a and determining the main geometric parameters of the draft tubes with elbow 12a are given.
混流式水轮机在非设计工况点下运行时，尾水管内部的非定常流动是由死水域和螺旋涡带的动态行为引起的，尾水管上部的螺旋涡带旋转引起流动的基频脉动。
The unsteady flow in a draft tube of Francis turbine under the off-design operation is produced by the dynamic behavior of a helical vortex rope with the dead core.
输水管道将被深埋地下以避免水分蒸发，输送至沙漠的水则被用来培植广林尾巨桉。
The pipes, buried underground to avoid loss to evaporation, would irrigate fields of Eucalyptus grandis.
输水管道将被深埋地下以避免水分蒸发，输送至沙漠的水则被用来培植广林尾巨桉。
The pipes, buried underground to avoid loss to evaporation, would irrigate fields of Eucalyptus grandis.
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