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双语推荐：水头损失

为了探索采用Fluent 软件模拟研究长距离倒虹吸水头损失的准确性，利用计算流体力学软件Fluent 的水气两相流VOF法，采用三维标准k- E模型对长距离倒虹吸水头损失进行模拟计算。计算中考虑壁面粗糙程度，设置不同的粗糙度模拟小洼槽倒虹吸水头损失，从而得到玻璃钢管材粗糙度范围。对比较大流量下水头损失的模拟值与实测值，表明通过设置粗糙度模拟长距离倒虹吸水头损失的方法可行，但网格划分对结果的影响大小还需进一步研究。

In order to explore the accuracy of Fluentsoftware in simulating the head loss of long-distance inverted siphon, the wa-ter-air two-phase flowVOF method in the computational fluid dynamics software Fluentand a three-dimensional standard k~Emodel were used to simulate the head loss of long-distance inverted siphon. The calculations considered wall roughness by set-ting differentroughness simulate head loss of smal-trough inverted siphon to obtain the roughness of glass fiber reinforced plastic pipe. The measured and simulated head loss values under large flowconditions were compared, which showed thatitis feasible to setthe roughness of the long-distance inverted siphon to simulate head loss. However, the effects of mesh discretiza-tion on the head loss results need further research.

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在灌区渠道系统中,长喉槽是一种常用的测流设施,其测量精度依赖于水头损失的精确计算。为了检验其测流精度及有效性并加以改进,该文进行了一系列模型试验。试验结果表明对于进口有侧收缩的长喉槽,现有理论模型的计算流量皆大于实测值。该文认为这是由于现有的基于边界层理论的水头损失计算模型忽略了上游收缩段局部水头损失引起的。在试验数据和分析的基础上,该文引入了进口段局部水头损失?Hcon,对于侧收缩比分别为1∶2、1∶2.5、1∶3的长喉槽,建议局部水头损失系数分别取为0.317、0.263和0.203。在引入进口段局部水头损失后,计算误差从9.59%减少到了4.14%,研究结果为侧收缩长喉槽测流计算精度的提高提供了重要参考。

Long-throated flume has been widely used as a flow measurement structure in irrigation channel systems. The key element of the long-throated flume is a throat, the length of which is longer than one and one-half times of the upstream energy head referenced to the throat invert or crest. Measurement accuracy of this flume is based on an accurate prediction of head-loss. This long throat causes the streamlines to be straight enough to sufficiently approximate hydrostatic pressure distributions. Replogle proposed a mathematic model for discharge calculation of various kinds of measurement structures. It is claimed that the model can achieve an accuracy within 2% based on the results of laboratory studies (within the range 0/07

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针对玻璃钢管沿程水头损失计算问题，根据水力学原理，采用公式对比的方法，论证了海曾2威廉公式的合理性，并修正了相关参数；同时以新疆小洼槽倒虹吸为例，利用不同公式计算水头损失值，然后与实测数据比较分析，发现管径小于2000 mm 玻璃钢管的水头损失计算宜采用海曾2威廉公式，沿程摩擦系数采用相应的修正值；管径大于2000 mm 宜选用齐恩公式和达西公式的组合。

As for the calculat ion of friction head loss in the FRP pipe, based on the hydraulics principle, several formulas were compared and the rationalit y of H azen-Williams formula w as demonstrated, and the relevant parameters w ere modified. T he study adopted different formulas to calculate the water head loss in the case of small-trough inverted siphon in Xinjiang. The re-sults of the com parison betw een the calculated and observed head loss suggested that: ( 1) H azen-Williams formula can be used in the friction head loss calculation in the FRP pipe w ith diameter less than 2 000 mm, and the frictional coefficient needs to be modified; and ( 2) the combinat ion of JiEn formula and Darcy formula can be used in the friction head loss calculat ion in the FRP pipe w ith diameter larger than 2 000 mm.

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以"怀柔应急水源地21号对井供水管线跨怀河工程"为背景,探讨了按水力坡降或比阻以及依据谢才公式计算铸铁管水头损失的方法,并对这两种计算方法的异同优劣进行了阐述,指出在长管工程中采用查表法计算管道水头损失更简单快捷。

Taking the“Huairou emergency water source No. 21 double well water supply pipelines crossing Huai River project”as the back-ground,this paper discussed the method to calculate the cast iron pipe head loss as hydraulic gradient or resistance formula,and elaborated the similarities and differences,advantages and disadvantages of this two calculation methods,pointed out that using look-up table method to calcu-late pipeline head loss was more simple and quick in long pipe engineering.

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就锦屏二级电站引水隧洞,根据实测水头损失、反算沿程水头损失糙率系数过程中的一些经验和认识进行总结,提出了:(1)应尽量选取局部损失所占比例较小的洞段来计算沿程水损,并应计入测点底部流速头,以提高计算精度;(2)在引水隧洞平均水力半径的计算过程中,不能采用等动量或者等体积的方法,必须遵循水损相等的原则进行当量等观点,供参考。

Calculation method for roughness coefficient of water conveyance tunnel in JinpingⅡhydro-power station is summarized in this paper. Two viewpoints are presented:(1) in order to improve the cal-culation accuracy, we should select the section of tunnel where local loss is smaller to calculate rough-ness coefficient and the bottom velocity head should be included;(2) during the calculation of average hydraulic radius of the diversion tunnel, the method of equal volume or equal momentum cannot be used. The principle of equal equivalent water loss should be followed.

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针对回水冲渣泵运行的现状,通过技术分析,发现回水冲渣泵水头损失很大;并利用水泵切削方程式理论采用减小叶轮直径的方法,降低水头损失,以达到节能、经济的效果。

Through technical analysis of current conditions of the backwater slag washing pump, it was found that the pump had big head loss. The diameter of impeller was reduced using pump cutting equation theory to lower water head loss and achieve energy-saving and economic effect.

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基于计算流体力学(CFD),对双机共用尾水调压室的几种典型工况进行了数值计算,得到调压室底流速分布、水头损失系数和水流通过两个阻抗孔流进(出)调压室的流量。通过分析各工况的模型内部流动状态,并与模型试验结果进行对比,发现:水流进(出)调压室水头损失系数随流量比增大而增大,且分流工况单台机组运行时损失系数值比两台机组运行时小;单机运行时,水流流经两个阻抗孔进(出)调压室的流量大小不一定相等,且随流量比变化而变化。

In this paper, computational fluid dynamics (CFD) method was used to simulate several typical working conditions of tailrace surge tanks shared by two units.The flow velocity distribution under the surge tank, head loss, and flow rate of water flowing into or out of the surge tank through the two impedance holes were obtained and analyzed. In addition, the simulated flow patterns under different working conditions were analyzed and compared with those obtained from experimental results. The results indicated that the head loss coefficient for w ater flow ing into or out of the surge tank increases with the increasing of flow rate and the head loss coefficient under single2unit operation is lower than that under two2unit operation.Moreover, the flow rates of water flowing into or out of the surge tank through the tw o impedance holes shared by two units were not the same under single2unit operation and they were affected by the variation of discharge ratio.

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抽水蓄能电站进／出水口有进流和出流两种工况，进／出水口水流呈双向流动，水力条件较复杂，对水流流态要求较高。因此，为观测各工况水流流态和水头损失大小，进一步完善进／出水口的结构布置和尺寸，对下库进／出水口进行了数值模拟计算。根据隧洞中水流的运动为有压流这一特点，建立了隧洞压力驱动三维水动力模型，考虑了进／出水口上游一定长度隧洞在内的三维空间计算域，采用k－ε紊流模型，通过对隧洞内压力流的数值模拟，分析研究了各工况下流道分离比、流速、流态及水头损失等水力特性。研究表明：将中边孔导流隔墩尾部位置进行调整能有效改善中、边孔分流比，流速不均匀系数也有所改善，水头损失无明显变化。

In order to observe the condition of the flow regime and head loss size,to further improve the structure arrangement and size of in-let/outlet,optimize the in and out of the nozzle arrangement,especially for a numerical simulation for inlet/outlet under the library. Accord-ing to the tunnel pressure flow,the movement of water in the characteristics of tunnel pressure driven three-dimensional hydrodynamic mod-el was established,considering the in and out of the gate lengths upstream tunnel,three-dimensional calculation domain,the k - epsilon turbulence model,through the numerical simulation of the pressure in the tunnel flow under various operating conditions analysis to study the flow separation ratio,flow velocity,flow pattern and hydraulic characteristics such as head loss. Study shows that by moving the position of the side hole diversion pier end insulation,can effectively improve,side hole in the diversion ratio,velocity of non-uniform coefficient also has been improved,

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泵站建成运行管理往往需要了解水泵的实际运行工况，即了解水泵运行的工作点，管路系统尤为重要，管路模型有Colebrook-White、Hazen-Williams和固定系数3种，不同模型下计算结果不同，但相差不大。在长距离供水工程中，沿程水头损失是引起压降的主要因素，局部水头损失可忽略不计。借助Flow master平台对乡宁供水工程组建网络模型进行稳态模拟，并对不同管道模型模拟结果进行比较，以期对Flow master平台在供水泵站稳态仿真模拟的应用提供借鉴。

Pumping station management often need to know the actual operating conditions of the pump ,that you need to know at what point pumps work on the performance curve ,piping sys-tem is particularly important ,and different pipe model have different calculation results .In long distance water supply engineering ,the main factor of causing the pressure drop is friction ,and the local head loss can be neglected .With the help of Flowmaster platform ,network model was built to simulate steady-state with different pipe models and to compare the results for the purpose of providing reference for steady simulation application in the pumping station .

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基于室内坡面流实验，研究了人工植被分布变化对坡面流水动力学特性的影响。试验包括“细管整齐排列”、“细管1/2错开排列”、“细管1/4错开排列”、“粗管1/2错开排列”等植被分布方式。研究结果表明植被分布变化对坡面流扰动程度的影响显著，从而使得不同植被分布方式下的坡面流达西阻力系数、局部水头损失系数差异性很大。而随流量增大达西阻力系数、局部水头损失系数都呈现先减小后增大的趋势。

With the influence of different distribution of artificial vegetation ,the characteristics of overland flow and the corresponding sediment transport were herein investigated experimentally.The experimental distribution of artificial vegetation consisted of uniform and non-uniform modes.The results show that the flow resistance coefficient and the local head losses of overland flow were significantly affected by the different vegetation dis-tribution.However the Darcy-Weisbath resistance coefficient and the local head losses first decreases and then rises with the increasing of flow rate.