大功率工业透平末三级叶顶间隙流动数值研究

发布时间：2018-02-28 05:04

本文关键词： 大功率工业透平末级叶顶间隙平衡凝结模型泄漏量流固耦合　出处：《大连理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：为保证轴流汽轮机的动静元件在运行中不发生碰磨,设计时会在动叶叶顶和汽缸内壁之间留有一定的间隙。因此,动叶叶顶存在间隙泄漏流动,泄漏引起的泄漏涡与主流的掺混作用所造成的损失已经成为提高汽轮机的气动性能和效率必须要解决的关键问题。目前,对10万千瓦等级的大功率工业汽轮机而言,尚没有准确计算其叶顶泄漏损失的模型,这已经影响到该等级工业汽轮机的效率核算和性能评估；并因此降低了我国同类型产品在国际市场的竞争力,成为更高等级工业汽轮机设计与开发的瓶颈。为了准确评价该等级工业汽轮机末几级的级性能,并探究末几级叶顶泄漏的特点,本文依据杭州汽轮动力集团有限公司提供的某大功率工业汽轮机末三级叶片数据和设计参数,建立了末三级联算的计算模型,首先选用平衡两相湿蒸汽模型,对三级主流道内和间隙内部的流动进行了数值模拟研究,详细分析了间隙泄漏流动的形成和发展,充分阐述了间隙泄漏流动和主流之间的相互作用。其次对不同进口流量工况进行了数值计算,对比了不同工况下汽轮机末三级的性能,并分析了不同进口流量对末三级流动以及对叶顶间隙泄漏量的影响。然后在设计工况下,改变末三级动叶叶顶间隙值,探究不同叶项间隙值与汽轮机级性能之间的相互关系,分析了不同间隙下,泄漏流动和主流之间的关系。分析了动叶叶顶间隙变化和轴向间隙变化对末三级性能参数的影响,提供了一种末三级性能参数随末三级动叶叶顶间隙变化的关系式拟合方法,并拟合了多变效率以及末三级动叶叶顶泄漏量与末三级动叶叶顶间隙的关系式,之后对结果进行误差分析,证明关系式具有较高的可信度。最后分别采用单纯考虑叶片转动,单向流固耦合和双向流固耦合方法对动叶进行径向变形计算,并在计算中考虑因动叶径向变形导致叶顶间隙减小带来的影响,对比分析了采用不同的固体变形计算方法时,叶片在高速转动的情况下的径向伸长量,并分析了叶顶径向伸长量和末三级的性能参数的关系。本文研究的结论可为今后该等级的工业汽轮机进一步的市场开拓提供一定的理论支撑,同时也为更高等级的工业透平的研发奠定理论基础。
[Abstract]:In order to ensure that the static and static components of the axial flow turbine do not collide in operation, there will be a certain gap between the top of the moving blade and the inner wall of the cylinder in the design. The loss caused by leakage vortex mixing with mainstream has become a key problem to be solved to improve the aerodynamic performance and efficiency of steam turbine. There is no accurate model for calculating the leakage loss at the top of the blade, which has affected the efficiency accounting and performance evaluation of the industrial steam turbine of this class, and thus reduced the competitiveness of the same type of products in the international market. It has become the bottleneck in the design and development of higher grade industrial steam turbine. In order to evaluate the performance of the last stage of the industrial steam turbine accurately, and to explore the characteristics of the leakage of the top blade of the last stage of the industrial steam turbine, Based on the data and design parameters of the final three stage blade of a high power industrial steam turbine provided by Hangzhou Turbine Power Group Co., Ltd., the calculation model of the final three stage combined calculation is established in this paper. First, the equilibrium two phase wet steam model is selected. Numerical simulation of the flow in the three-stage main channel and in the clearance is carried out, and the formation and development of the leakage flow in the gap are analyzed in detail. The interaction between the clearance leakage flow and the mainstream is fully expounded. Secondly, the numerical calculation of different inlet flow conditions is carried out, and the performance of the last stage of the turbine under different working conditions is compared. The influence of different inlet flow rate on the flow at the end of the third stage and on the leakage of the tip clearance of the blade is analyzed. Then, under the design condition, the relationship between the clearance value of the blade and the performance of the steam turbine stage is studied by changing the clearance value of the tip of the last three stage moving blade. The relationship between leakage flow and mainstream under different clearance is analyzed, and the influence of the change of tip clearance and axial clearance of moving blade on the final three stage performance parameters is analyzed. In this paper, a fitting method of the relation between the performance parameters of the last three stage and the top clearance of the last three stage moving blade is presented, and the relationship between the variable efficiency and the leakage rate between the top of the last three stage moving blade and the top clearance of the last three stage moving blade is fitted. Finally, the radial deformation of the moving blade is calculated by considering the blade rotation, unidirectional fluid-solid coupling and bidirectional fluid-solid coupling, respectively. In the calculation, the influence of blade tip clearance decrease caused by radial deformation of moving blade is considered, and the radial elongation of blade under the condition of high speed rotation is compared and analyzed with different calculation methods of solid deformation. The relationship between the radial elongation of the blade top and the performance parameters of the last stage is analyzed. The conclusion of this paper can provide some theoretical support for the further market development of the industrial steam turbine of this grade in the future. At the same time, it also lays a theoretical foundation for the research and development of higher grade industrial turbine.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TK269.4

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