非轴对称端壁涡轮叶栅内湿蒸汽流动特性研究

发布时间：2017-12-27 23:26

本文关键词：非轴对称端壁涡轮叶栅内湿蒸汽流动特性研究　出处：《哈尔滨工业大学》2016年硕士论文　论文类型：学位论文

【摘要】：随着科技的不断进步,人们对于动力机械中能量转化效率的问题也愈发重视,而蒸汽轮机作为火力发电以及舰艇驱动中重要的动力装置,如何提高其运行效率一直都是科研工作中最优先考虑的问题。由于工质为水蒸气,在真实的流动现象中,蒸汽轮机叶栅的内部不仅存在着叶轮机械里不可避免的二次流问题,同时也存在着复杂的水蒸气相变问题。因此,减小蒸汽轮机内部的二次流损失以及湿蒸汽损失对于未来高性能蒸汽轮机的设计具有极其重要的意义。由于非轴对称端壁造型控制叶栅中二次流损失的机理是改变了叶栅中的压力场分布,而压力场的改变也能够影响水蒸气的凝结。为了研究如何同时控制二次流和湿蒸汽这两种损失,在本文中尝试对White叶栅的下端壁进行非轴对称端壁造型的改造。在研究的开始,首先确定选用了基于三角函数法的端壁造型方法,使用了这种端壁造型方法的叶栅能够在不同的轴向位置生成不同高度的非对称端壁造型,本文中构造的数值模型,网格数为80万,采用SST湍流模型,通过将数值计算结果与实验结果进行对比,证明本文采用SST湍流模型计算得到的结果是可靠的。在本文第三章中一共建立了九种不同的模型,通过对这九种不同算例的模拟,并将结果同原型叶栅进行对比,可以发现当非轴对称端壁造型位于叶栅中部时,叶栅中二次流损失和湿度均有所减少,其中,造型峰值位于叶栅中部时,峰值占5%叶高的方案可以使22%叶高以下的二次流损失减少2.1%,使30%叶高以下的湿度减少1.2%;峰值占10%叶高的方案可以使26%叶高以下的二次流损失减少3.5%,使30%以下叶高的湿度减少5.3%。同时,在本文中,还对控制效果较好的两个造型方案进行了攻角适应性验证,从数值模拟的结果可以看出,应用了非轴对称端壁造型的White叶栅攻角适应性良好。在正攻角来流条件下,20%以下叶高的二次流损失略有增加,但是叶栅出口截面处平均气动参数变化不大;在负攻角来流条件下,叶栅内不仅二次流损失减小,叶片吸力面侧近端壁处高压区域随着攻角增大面积逐渐变大,并且逐渐向叶栅中后部移动,使得叶栅吸力面中部的凝结现象得到了抑制。
[Abstract]:With the continuous progress of science and technology, people increasingly attach importance to energy efficiency problem of power machinery, and steam turbine power plant as an important driving power and ships, how to improve the efficiency of scientific research work has always been the top priority in question. Because the working fluid is water vapor, in the real flow phenomenon, there is not only the two time flow problem in turbomachinery, but also the complex vapor phase transformation problem. Therefore, it is of great significance to reduce the two flow loss and the loss of wet steam inside the steam turbine for the design of the future high performance steam turbine. The mechanism of non axisymmetric endwall profiling control loss of two flow cascade is changed Ye Zhazhong's pressure distribution and pressure field changes can also affect water vapor condensation. In order to study how to control two losses of two times and wet steam at the same time, we try to reconstruct the bottom end wall of White cascade with non axisymmetric end wall. At the start of the study, first determine the selection of the end wall modeling method of trigonometric function method based on cascade using the end wall modeling method can generate different shapes of non axisymmetric endwall height at different axial positions, the numerical model constructed in this paper, the grid number is 800 thousand, the SST turbulence model, the the numerical results are compared with the experimental results, the results calculated using the SST turbulence model proved to be reliable. In the third chapter of this paper has established nine different models, based on the simulation of the nine different examples, and the results were compared with the prototype cascade, can be found when non axisymmetric endwall profiling in cascade middle, loss and humidity two cascade flow decreased, among them, other peak located in the cascade middle peak, accounted for 5% of the blade height scheme can make the 22% leaf high under two secondary flow loss is reduced by 2.1%, the 30% leaf high humidity below 1.2% reduction; peak accounted for 10% of the blade height scheme can make the 26% leaf high under two secondary flow loss is reduced by 3.5%, the following 30% leaves high humidity is reduced by 5.3%. Meanwhile, in this paper, we also verify the adaptability of two modeling schemes with good control effect. From the result of numerical simulation, we can see that the White axis with non axisymmetric endwall shape has good adaptability to attack angle. In the angle of attack flow conditions, the following 20% leaves two times higher flow loss increases slightly, but the cascade outlet average aerodynamic parameters change little; the negative angle of attack flow conditions, not only in the two cascade secondary flow loss is reduced, the suction side near the end wall of the high-pressure region increases with the angle of attack area becomes larger, and gradually to the rear of the cascade moving condensation cascade suction surface central suppressed.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TK261

【相似文献】