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国内外一般水电站,下游水位(尾水位)是不予控制的,而水轮机的装机高程则按较不利的水轮机允许吸出高度来加以考虑。以所周知,水轮机的允许吸出高度是随着它的工况不同而变化的,也就是在不同的水头和不同的负荷下,其H_s允许值是不同的。而电站一经建成,下游尾水区地形固定,下游尾水位随着电站负荷不同(即流量不同)而变化。由于水轮机安装高程已经确定,则尾水位与水 相似文献
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含沙水流对水轮机导叶部件磨损的数值模拟 总被引:3,自引:1,他引:3
建立了低浓度固液两相流(平均固体容积浓度Cv〈1%,即对于沙水,含沙量低于20kg/m^3)Eulerian-Lagrangian混合湍流模型。给出了颗粒-壁面碰撞模型和为韧性金属材质的水轮机过流部件的磨损模型。利用这些模型可数值模拟水轮机中含沙水流的流动、沙粒在水轮机过流通道内的浓度分布、运动轨迹及水轮机中含沙水流的流动、沙粒在水轮机过流通道内的浓度分布、运动轨迹及水轮机过流部件的磨损率。本文模 相似文献
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针对双沟水电站的模型验收工作,将效率试验、飞逸试验、空化试验、补气试验与预试验结果进行对比,通过复核试验验证了HLA883-LJ-400型水轮机在各项性能及指标上均满足合同要求,从而确定了机组的安装高程及流道尺寸,并为双沟水电站水轮机运行提供了可靠的依据。 相似文献
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水轮机的汽蚀破坏,虽然已经研究了半个多世纪,但到目前仍是一个迫待解决的问题。在水轮机运行中,仍然存在明显的汽蚀破坏。在某种程度上说明水轮机汽蚀破坏的机理还没有充分被认识。此外,选择水轮机安装高程时,如不考虑遭受汽蚀破坏的水轮机部件的材质,那也是错误的。本文在总结水轮机现有运行经验和分析实验室研究成果的基础上作一尝试,并根据使用材料的耐汽蚀性能提出选择水轮机吸出高度的依据。正确地选择材料和允许的吸出高度,可以保证水轮机不受汽蚀破坏而安全地运行。 相似文献
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旬阳钟家坪水电站溢流坝的面流消能设计与试验 总被引:1,自引:0,他引:1
研究了旬阳钟家坪水电站溢流坝的面流消能问题,通过分析确定了合理的溢流坝跌坎高度、鼻坎挑角和反孤半径等参数,并对下游水面线、水面波动和流速分布等情况进行了试验研究,为面流消能设计提供了依据,保证了设计的可靠性。 相似文献
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中小型水电站水轮机转轮改型设计的必要性和可行性 总被引:1,自引:0,他引:1
中小型水电站技术改造是水电事业发展的重要组成部分,本文通过对我国中小型水电站发展现状的论述,分析了在中小型水电站改造中水轮机转轮改型设计的必要性和可行性,并介绍了当前水轮机转轮设计、测试和制造方面的新技术。 相似文献
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介绍了大型电机吸风嘴成型工艺、坯料尺寸确定及模具结构。该成型工艺克服了口部开裂、凸缘翘曲及脱模困难等缺点,具有操作简单、制品合格率高、适应范围广等优点,尤其适合高度大,翻边困难的零件成型。 相似文献
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Yu. A. Fetisova B. V. Ermolenko G. V. Ermolenko S. V. Kiseleva 《Thermal Engineering》2017,64(4):251-257
We studied the information basis for the assessment of wind power potential on the territory of Russia. We described the methodology to determine the parameters of the Weibull function, which reflects the density of distribution of probabilities of wind flow speeds at a defined basic height above the surface of the earth using the available data on the average speed at this height and its repetition by gradations. The application of the least square method for determining these parameters, unlike the use of graphical methods, allows performing a statistical assessment of the results of approximation of empirical histograms by the Weibull formula. On the basis of the computer-aided analysis of the statistical data, it was shown that, at a fixed point where the wind speed changes at different heights, the range of parameter variation of the Weibull distribution curve is relatively small, the sensitivity of the function to parameter changes is quite low, and the influence of changes on the shape of speed distribution curves is negligible. Taking this into consideration, we proposed and mathematically verified the methodology of determining the speed parameters of the Weibull function at other heights using the parameter computations for this function at a basic height, which is known or defined by the average speed of wind flow, or the roughness coefficient of the geological substrate. We gave examples of practical application of the suggested methodology in the development of the Atlas of Renewable Energy Resources in Russia in conditions of deficiency of source meteorological data. The proposed methodology, to some extent, may solve the problem related to the lack of information on the vertical profile of repeatability of the wind flow speeds in the presence of a wide assortment of wind turbines with different ranges of wind-wheel axis heights and various performance characteristics in the global market; as a result, this methodology can become a powerful tool for effective selection of equipment in the process of designing a power supply system in a certain location. 相似文献
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针对哈尔滨第三发电厂二期工程国产 2台 600 MW发电机组循环水泵的选型及其引水流道的优化设计问题,详细论述了循环水泵的优化选型,并给出了优化后的引水流道的工艺布置和各项水力参数,也首次推出了水泵吸入喇叭口新体型的设计研究成果。本课题的研究在大型立式斜流泵的防空化、防振动、防噪音等方面跨出了新的一步。该研究成果经工程实际应用,得到了很好的效果,因此对类似工程具有推广应用的价值。 相似文献
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Abdelhakim Latreche Zahir Ouennoughi 《International Journal of Numerical Modelling》2015,28(2):231-238
In this study, we show clearly why unexpected observations have been reported in the current–voltage curves of Schottky diodes, containing barrier inhomogeneities generated by using the analytical results based on a Gaussian distribution model of barrier heights. The Chand's calculations have shown that the current (saturation current) at low temperatures may exceed the current (saturation current) at high temperatures when the effective barrier height is calculated from an appropriate integral with integration limits −∞ and +∞. In this new study, we show that the method followed by Chand to remove these anomalies is not accurate enough. We prove that the origin of these anomalies stems from the nature of a proper function f(φ) that moves to the negative barrier heights and takes large value of the integral at low temperatures than at high temperatures when it has large standard deviation (σ) and the discrepancies are not due to the integration limits as Chand concluded. In order to obtain results consistent with the thermionic emission–diffusion theory, the standard deviation must have lower values. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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水煤浆球在流化床内的燃烧试验及灰色关联分析 总被引:1,自引:0,他引:1
为了研究水煤浆在流化床内的燃烧状态,用人工制备的水煤浆球模拟水煤浆滴在炉内下落后形成的浆球,投入不同运行参数(床温、流化数、床料高度)下的以石英砂为床料的热态流化床内进行燃烧试验。其中床温为650、750、850和950℃,流化数W为3、3.5、4和4.5,床料高度为30、50、70和90 mm。分别在15、30、45、60和75s 5个不同的流化时间后取出浆球测量其中残留固定碳占投入浆球内固定碳的质量百分比,分析各参数对燃烧过程的影响,并用灰色关联分析确定各运行参数对该质量百分比的影响排序,可确定床料高度对其影响最小,在前期和后期流化数的影响最大,中期床温影响最大。 相似文献