核电汽轮机级内湿蒸汽凝结流动的特性分析

发布时间：2019-06-26 13:17

【摘要】：核电汽轮机组大部分处于湿蒸汽状态下运行,因此深入了解湿蒸汽自发凝结流动的机理,对于提高核电汽轮机组的经济性和安全性具有重要的实际意义。本文采用湿蒸汽自发凝结非平衡相变模型,对600MW核电汽轮机高压缸级内的湿蒸汽自发凝结流动进行三维数值分析,主要的工作内容如下:对定常流动条件下,不同蒸汽状态和不同工况下的湿蒸汽自发凝结流动进行数值分析。结果表明:蒸汽自发凝结的瞬间,会导致叶片轴向距离上的总压发生突变。不同蒸汽状态下,过冷蒸汽的凝结量最大,其动压值亦最高。沿叶高方向,凝结首先发生在叶片上部。随着入口质量流量减小,级内流动损失增加,汽轮机效率下降。随着蒸汽来流湿度增大,级内流场的气动性能变差,级的效率下降。对非定常流动条件下,湿蒸汽自发凝结流动进行数值分析。结果表明:非定常流动的动静干涉现象导致湿蒸汽级内的轴端功率下降0.266%。非定常流动过程中的静叶尾迹现象致使下游动叶通道内自发凝结的液滴直径增大,动叶前缘位置的液滴数增加。非定常凝结流动的压力位势作用使得动叶出口平均压力提高。非定常流动引起湿蒸汽凝结的湿汽损失提高19.917%。本文对某核电汽轮机高压级湿蒸汽自发凝结流动的研究,有利于提高机组的经济性和安全性,为核电汽轮机实际运行提供理论依据。
[Abstract]:Most of the nuclear turbine units operate in wet steam state, so it is of great practical significance to understand the mechanism of spontaneous condensation flow of wet steam in order to improve the economy and safety of nuclear power turbine units. In this paper, the three-dimensional numerical analysis of wet steam spontaneous condensation flow in high pressure cylinder stage of 600MW nuclear power turbine is carried out by using the non-equilibrium phase transition model of wet steam spontaneous condensation. The main work contents are as follows: the spontaneous condensation flow of wet steam in different steam states and different working conditions under steady flow conditions is analyzed. The results show that the total pressure on the axial distance of the blade changes suddenly when the steam condenses spontaneously. Under different steam conditions, the condensation amount of supercooled steam is the largest, and the dynamic pressure value is the highest. Along the direction of leaf height, condensation first occurs in the upper part of the blade. With the decrease of inlet mass flow rate, the flow loss in stage increases and the efficiency of steam turbine decreases. With the increase of steam inflow humidity, the aerodynamic performance of the stage flow field becomes worse and the efficiency of the stage decreases. Numerical analysis of spontaneous condensation flow of wet steam is carried out under the condition of unstable flow. The results show that the axial power in the wet steam stage decreases by 0.266% due to the static and static interference of the unsteady flow. The phenomenon of static blade wake in the process of unstable flow increases the diameter of spontaneous condensation droplets in the downstream moving blade channel and the number of droplets in the leading edge of the moving blade. The average pressure at the outlet of the moving blade is increased by the pressure potential of the unstable condensate flow. The wet steam loss of wet steam condensation caused by unstable flow is increased by 19.917%. In this paper, the study of spontaneous condensation flow of high pressure stage wet steam in a nuclear power turbine is helpful to improve the economy and safety of the unit and provide a theoretical basis for the actual operation of nuclear power turbine.
【学位授予单位】：东北电力大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM623

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