共查询到18条相似文献,搜索用时 109 毫秒
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开式和闭式离心泵进口回流的研究 总被引:6,自引:1,他引:5
利用毕托管对闭式和开式不同叶顶间隙的离心泵叶轮进口流场进行了动态测试,另外对开式叶轮吸入盖上的静压分布也进行了动态测试,并对叶轮流道内流场进行了可视化观察,弄清了小流量工况下叶片间的回流分布情况及上述不同叶轮对回流发生的影响及其原因。 相似文献
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离心泵叶轮参数对进口回流的影响 总被引:3,自引:0,他引:3
本文对不同叶片进口角、叶片数、不同叶顶间隙的开式和闭式离心叶轮共12种叶轮的进口流场和回流发生情况进行了探针的动态测试和可视化观察.弄清了上述叶轮参数对进口回流初始流量和进口流场的影响. 相似文献
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系统研究了咪唑类氮氧自由基作为pH自旋探针的ESR波谱特性。用量子化学方法AM1研究了pH自旋探针分子的几何结构、电子结构及电子自旋密度分布,aN理论值与实验结果基本一致,得到了pka值与电子密度关系曲线,指出它们在生命科学中的应用前景。 相似文献
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提出一种基于激光与CCD的复合式测量方法,结合二者的优势,通过测量同一标准球球心的位置标定出了二者光轴的位置关系,有效地把二者测量的数据融合到同一个坐标系中,从而实现高精度的3维测量。在对所测靶丸表面数据进行去噪处理后,采用拟牛顿法,以CCD所测惯性约束聚变(ICF)靶丸直径作为部分待求参数的初始值,可以有效避免该方法容易陷入局部最优化的缺陷。从而快速、准确地实现靶丸球度误差的测量。分别在两种测量模式下进行了实验,结果验证了该方法的有效性与鲁棒性。 相似文献
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检流计内阻测量的探究 总被引:1,自引:1,他引:0
本文以检流计内阻的测量为例,运用"探究式"教学方法,引导学生进行科学探究,并突出了对探究过程的研究;用标准不确定度对测量结果进行科学评定,着重培养学生的科学探究能力,取得较好的教学效果. 相似文献
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A technique to calibrate faro retro probe using laser tracker system (LTS) is presented. The deep-access retro probe enables LTS to perform three-dimensional (3D) measurements of surface hidden features. It has been shown that misalignment errors are the key contributor to measuring errors of retro probe. A device for measuring misalignment errors of retro probe is invented. Theoretical analysis and experiment show that using this technique to calibrate retro probe, the misalignment errors of retro probe can be eliminated effectively and quickly. 相似文献
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P. Špatenka 《Czechoslovak Journal of Physics》1988,38(9):996-1004
The influence of the rf-plasma potential oscillations in the planar system with a small ratio of the area of the powered electrode to the area of the grounded surfaces has been investigated. Although no effect of the blocking rf filters in the probe circuit on the probe measurements has been found, the ac connection of an auxiliary electrode having a large surface to the measuring probe have caused a considerable shift of the probe characteristic. The rf-plasma potential oscillations can, therefore, distort the probe measurements and their influence must be taken into account. A new method is proposed that allows to estimate the error caused by these oscillations. 相似文献
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A method based on inverse photogrammetry and fringe analysis is presented for 3D coordinate measurement. Measurement system mainly consists of a micro-camera fixed on one end of a measuring rod, a measuring probe on the other end and a liquid crystal display screen for displaying 2D fringe pattern in the measurement. In the measurement process, the probe contacts the surface of the measured object, and the CCD camera captures the stripes image on displays screen. The coordinates of camera principal point in the world coordinate system may be determined by the phase information carried in the fringe pattern. The coordinate relations between the principal point of the camera and the measuring probe can be determined with a least square optimization technique in camera coordinate system. This method has the advantage of large measurement range, good flexibility, and portable, which is suitable for field measurement. A result of our method is compared with that of the Coordinate Measuring Machine (CMM), which shows that the measurement accuracy of this method can meet accuracy requirement of the field measurement in large dimension. 相似文献
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考虑粘性及展向掺混的轴流和离心组合压气机流动分析 总被引:1,自引:0,他引:1
本文研究建立了具有复杂流道形状的一体化轴流和离心组合压气机内部流动的数值计算方法,考虑到湍流扩散和粘性掺混,对不同类型的组合压气机内部流场进行了计算,根据计算结果详细分析了压气机的流动特性和气动性能,为建立先进的轴流和离心组合压气机气动设计体系,提供了工程实用的计算机程序和设计分析方法。 相似文献
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1前言气液两相流广泛存在于动力、化工等工业过程中,到目前为止,人们已开发了大量的实验测定方法,用于研究气液两相流空泡份额等。但是对气泡速度的测量研究并不多,主要原因在于气泡速度测量的困难性。近几年人们尝试使用激光多普勒测速技术、颗粒轨迹测速技术等测量气泡速度,这些测量方法不仅系统复杂,而且还有相应的限制条件,适用范围有限。利用相关测速技术可以测量一维气泡速度,其原理是:设距离为L的上、下游两个测点的传感器在时间间隔T内测得的随机气泡信号为X(t)和Y(t),而且X(t)和Y(t)为平稳和各态遍历,则相关… 相似文献