汽轮机导向叶栅不同工况气动性能研究

发布时间：2018-02-05 21:44

本文关键词： 叶栅稠度冲角二次流　出处：《东北石油大学》2015年硕士论文　论文类型：学位论文

【摘要】：通过改变汽轮机进口导向叶栅的稠度,建立了三种稠度高压导向叶片栅模型,进行了空气动力特性的数值仿真,并对原型叶栅的进口冲角进行了变冲角特性气动性能数值研究。通过导向叶栅不同稠度和不同冲角的数值仿真及叶栅流动机理的研究,为国内研制具有独立知识产权的汽轮机技术提供理论支持。通过改变叶栅的稠度和进口气流冲角,对数值仿真结果进行分析总结,具体分析内容包括叶型截面静压系数分布规律、节距在子午面上平均静压系数分布规律、总压损失系数沿轴向的分布规律、节距在叶栅出口处平均总压损失系数沿展向分布规律和总压在出口横截面上的分布规律。对不同稠度直叶片进行了数值分析,静压系数沿叶型分布表明三种稠度的直叶片在后部加载叶型的特性明显,静压系数等值线在子午面上的分布表明流道内大部分是二维的层流流动,直到接近尾缘附近才进入三维湍流区,湍流区的大小随着导向叶栅稠度的增大而增大。总压损失在出口截面的分布表明稠度增加,损失区尾迹宽度将增大,上、下通道涡对应的损失核心变大。通过变化冲角的数值仿真,结果表明：后加载特性的仿真叶片改善了冲角适应性,在吸力表面和压力表面内冲角的变化基本没有改变静压在叶片表面的分布,但正冲角却增加了压力损失,而负冲角小幅度减弱压力损失。通过对叶栅内流场的各气动参数的分析,在不同冲角作用下,未发现有气流拥堵问题；上、下通道涡的变化时,随叶栅冲角增大而增强,带来的损失相应增大,尾迹脱落涡的形状与之类似,宽度随叶栅冲角的增大而增加,表明原型叶片栅对变冲角的适应性良好。
[Abstract]:By changing the consistency of turbine inlet guide cascade, three kinds of consistency high pressure guide blade cascade models are established, and the aerodynamic characteristics are numerically simulated. The aerodynamic characteristics of the inlet angle of incidence of the prototype cascade are numerically studied. The flow mechanism of the cascade is studied by numerical simulation of different consistency and angle of incidence of the guide cascade. This paper provides theoretical support for the development of steam turbine technology with independent intellectual property rights in China. The numerical simulation results are analyzed and summarized by changing the cascade consistency and the angle of incidence of inlet airflow. The detailed analysis includes the distribution law of the static pressure coefficient of the blade profile section, the distribution law of the average static pressure coefficient on the meridian plane and the distribution law of the total pressure loss coefficient along the axial direction. The distribution of the average total pressure loss coefficient at the outlet of the cascade and the distribution of the total pressure on the outlet cross section are analyzed numerically. The distribution of the hydrostatic pressure coefficient along the blade profile indicates that the three straight blades with different thicknesses have obvious characteristics of the blade shape at the back, and the distribution of the static pressure coefficient isoline on the meridian surface indicates that most of the flow channels are two-dimensional laminar flow. The size of the turbulent zone increases with the increase of the consistency of the guide cascade. The distribution of the total pressure loss in the exit section indicates that the consistency increases and the wake width of the loss area increases. The loss core corresponding to the lower channel vortex becomes larger. The numerical simulation of the angle of incidence shows that the simulation blade with the afterloading characteristics improves the adaptability of the angle of attack. The variation of the angle of incidence in the suction surface and the pressure surface basically does not change the distribution of static pressure on the blade surface, but the positive angle of incidence increases the pressure loss. The negative angle of incidence weakens the pressure loss by a small margin. By analyzing the aerodynamic parameters of the flow field in the cascade, there is no problem of airflow congestion under different attack angles, and the variation of the vortex in the upper and lower channel increases with the increase of the angle of incidence of the cascade. The loss increases correspondingly and the shape of wake shedding vortex is similar. The width increases with the increase of cascade angle indicating that the prototype blade grid has good adaptability to variable angle of incidence.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TK263.62

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