| 不同雷诺数下混流式水轮机密封间隙通道内流动特征分析 |
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| 引用本文： | 王文全,尹锐,闫妍.不同雷诺数下混流式水轮机密封间隙通道内流动特征分析[J].排灌机械,2014(7):611-616. |
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| 作者姓名： | 王文全 尹锐 闫妍 |
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| 作者单位： | 昆明理工大学土木工程学院,云南昆明650500 |
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| 基金项目： | 国家自然科学基金资助项目（11262008,11002063） |
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| 摘 要： | 针对水轮机密封间隙流道空间尺度相差较大,为实现对间隙流道的整体精确计算,文中采用分步投影法,求解间隙流道内不可压缩的Navier-Stokes方程.为更好地捕捉到间隙通道内的涡结构特征,对梳齿密封间隙采用六面体网格划分,在壁面边界处进行网格加密.扩散项采用二阶中心差分格式,对流项采用Quick迎风差分格式.通过数值求解得到不同流动雷诺数下间隙流道内速度、压力及涡量的分布规律,同时得到顶盖压力、间隙流道产生的轴向推力和转轴力矩.计算结果表明：流体从间隙进入梳齿空腔后,形成典型的旋涡耗能结构而耗散部分动能,对降压节流起到主要作用,同时,雷诺数对腔体内的旋涡形态影响较大.计算结果有助于理解不同流动雷诺数下水轮机密封间隙渗漏流道内复杂流动的真实物理机理以及密封间隙对轴系结构动力学特性的影响.
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| 关 键 词： | 混流式水轮机 间隙密封流道 梳齿密封 雷诺数 数值模拟 试验测试 |
Analysis of flow in side chamber and path of comb-labyrinth seal in Francis turbine at different Reynolds numbers |
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| Institution: | Wang Wenquan , Yin Rui , Yan Yah ( Faculty of Civil Engineering and Mechanics, Kunming University of Science and Technology, Kunming, Yunnan 650500, China) |
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| Abstract: | Since there is a large difference in geometrical scale in the side chamber and comb-labyrinth seal of Francis turbine runner, the fractional step method is used to solve the unsteady, three-dimensional, incompressible Navier - Stokes equations for the flow in the chamber and tortuous path of the seal. In order to capture vortex structure more exactly, the hexahedral mesh with refinement near the wall boundaries are adopted. The Quick upwind and second-order central difference schemes are se- lected for convection and diffusion terms, respectively. The velocity and vorticity profiles in the path of labyrinth seal are obtained at different Reynolds numbers; meanwhile the pressure distribution in the side chamber, axial thrust on the runner and torque on the shaft are estimated. It is turned out that a vortex structure can be developed as soon as the fluid enters the path of the labyrinth seal to consume a certain amount of kinetic energy, and a pressure drop is established to prevent the leakage. Note that the vortex structure is largely affected by Reynolds number. The results may be helpful in understan-ding the physical mechanism of complex flow in the path of comb -labyrinth seal and the influence of the seal on rotordynamics of Francis turbine. |
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| Keywords: | Francis turbine seal passage labyrinth seals Reynolds number numerical simulation experiment |
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