水泵水轮机内部流动模拟及分析

发布时间：2018-03-09 13:35

本文选题：抽水蓄能　切入点：水泵水轮机　出处：《华北电力大学(北京)》2017年硕士论文　论文类型：学位论文

【摘要】：抽水蓄能电站在电力系统中起着调峰填谷的作用。近年来其规模不断扩大。电网负荷复杂多变,要求其主要设备—可逆式水泵水轮机在不同工况间频繁转换,运行不可避免的进入非设计工况。当水泵水轮机运行在S特性不稳定区域的飞逸、水轮机制动等非稳定工况时,可能出现一些严重的问题,例如强烈的压力脉动、大轴摆动、异常的噪声和机组部件的疲劳断裂等。不同工况下水泵水轮机内部流动复杂,现场试验无法观测流动细节并得到详细数据。为了深入研究水泵水轮机不稳定现象产生的水力机理,本文采取数值模拟的方法对发电方向三种导叶开度(6°、21°和24°)五种工况(反水泵、零流量、水轮机制动、飞逸和水轮机工况)下的水泵水轮机进行分析。数值模拟采用商业软件与自主编程的复杂流动结构分析程序相结合的方式进行。建立涡识别方法的数学模型,重点分析水泵水轮机工况变化时和不同区域内复杂的涡结构,并量化不同区域内回流的位置和强度,理论计算并分析转轮上的受力情况。通过模拟分析,可以得出以下结论:(1)旋转不变涡分析方法在转轮及其附近无叶区内识别的涡的分布区域和涡量幅值较大。(2)不同导叶开度下,涡的形态存在差异。流量较低时,水泵水轮机内部流动恶化,转轮附近的涡显著。(3)回流主要发生在水轮机制动工况和飞逸工况,呈现明显的空间分布,而在水轮机工况很少发生。(4)转轮上所受的水激力可以分解为平行于轴向和垂直于轴向的力。这些力的产生与流动相关,在很大程度上受水泵水轮机运行工况和导叶开度的影响。
[Abstract]:Pumped-storage power station plays the role of peak regulation and valley filling in power system. In recent years, the scale of pumped-storage power station is increasing. The power network load is complex and changeable, which requires its main equipment, reversible pump turbine, to change frequently between different working conditions. When the pump turbine runs in the unstable region of S characteristic, the hydraulic turbine brake and other unsteady conditions, there may be some serious problems, such as strong pressure pulsation, big shaft swing, etc. Abnormal noise and fatigue fracture of unit parts. The internal flow of pump turbine is complicated under different working conditions. The flow details can not be observed and detailed data can be obtained in the field tests. In order to study the hydraulic mechanism of the instability of pump turbine in depth, In this paper, the numerical simulation method is used to study the three kinds of guide vane opening in the direction of power generation (reverse water pump, zero flow rate, hydraulic turbine braking) in five working conditions (reverse pump, zero flow rate, hydraulic turbine brake). The numerical simulation is carried out by the combination of commercial software and independently programmed complex flow structure analysis program. The mathematical model of vortex recognition method is established. In this paper, the complex vortex structures in different regions and operating conditions of pump turbines are analyzed, and the position and strength of reflux in different regions are quantified. The stress on the runner is calculated and analyzed theoretically. The following conclusions can be drawn from the following conclusions: (1) the vortex distribution and vorticity amplitude in the impeller and its adjacent vaneless region are different under the different guide vane opening. When the flow rate is low, the vorticity morphology is different. The internal flow of the pump turbine deteriorated, and the vortex near the runner was significant. The backflow occurred mainly in the braking condition and the flight escape condition of the turbine, which showed obvious spatial distribution. On the other hand, the induced forces on the runner can be decomposed into forces parallel to the axial direction and perpendicular to the axial direction. The generation of these forces is related to the flow and is greatly affected by the operating conditions of the pump turbine and the opening of the guide vane.
【学位授予单位】：华北电力大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TK730.1

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