透平持环高温蠕变和结构关系分析

发布时间：2019-04-24 02:31

【摘要】：透平部件是燃气轮机中承受温度最高的部件之一,透平静叶持环是透平部分中最大的铸钢件,是燃气轮机中温度最高,热负荷最大的大部件之一。透平静叶持环在热通道检修和大修中无法使用新部件替换,因此,透平静叶持环的使用寿命就决定整台燃气轮机寿命的重要因素之一,这关乎到整台燃气轮机的可靠性,因此分析透平静叶持环的应力、高温蠕变对部件的安全运行有着重要意义。本文主要研究内容如下:1)确定高温蠕变分析的边界条件首先分析冷却通道结构,对冷却流量的分配进行探索和计算,得到了冷却流量分配的基本原理和各级的分配量,并建立了计算模型;在此基础上,采用相近结构的对流换热系数的计算方法,计算得到了燃气轮机的持环各表面的换热系数;2)透平持环计算模型的建立与简化评估透平持环中冷却空气通道等结构对持环体的高温蠕变性能影响,在保证计算结果具有一定准确度的基础上,简化计算模型,并完成二维、三维建模。3)透平持环温度场、应力场计算分析以1)和2)的工作为基础,利用ANSYS计算软件,计算得到了包含持环内导热、对流换热和辐射换热等物理过程的温度场和应力场分布情况,得到透平持环的应力集中区域分布在前后的两个叶根槽处,最大应力在前叶根槽处,其初始应力最大值为125MPa;4)透平持环蠕变计算分析通过十万小时的蠕变仿真计算,发现模型的应力场发生了改变。在最初的1万小时,应力就降低至原来的50%以下,其最大应力点从前叶根槽处转移到了后叶根槽处,最大弹性应力值降至61MPa,应力松弛速度处于不断下降的趋势,至10万小时后,最大弹性应力降至42MPa;蠕变造成前后叶根槽处角度发生变化,并造成了静叶片的轴向变形,计算得出静叶片最大变形分别为1.24mm,均在蠕变允许的范围之内。
[Abstract]:Turbine component is one of the components which bear the highest temperature in gas turbine. Turbine blade holding ring is the largest steel casting in turbine part. It is one of the largest parts in gas turbine with the highest temperature and the largest heat load. It is impossible to replace the new components in hot channel maintenance and overhaul. Therefore, the service life of the turbine is one of the important factors that determine the life of the whole gas turbine, which is related to the reliability of the whole gas turbine. Therefore, it is of great significance for the safe operation of the parts to analyze the stress of the blade holding ring and the creep at high temperature. The main contents of this paper are as follows: 1) to determine the boundary conditions of creep analysis at high temperature, the structure of cooling channel is analyzed firstly, and the distribution of cooling flow rate is explored and calculated, and the basic principle of cooling flow distribution and the distribution quantity of all levels are obtained. The calculation model is established. On the basis of this, the heat transfer coefficient of each surface of the gas turbine holding ring is calculated by using the calculation method of the convection heat transfer coefficient of the similar structure. 2) the establishment and simplification of the calculation model of turbine holding ring and the simplified evaluation of the influence of the structure such as the cooling air passage in the turbine holding ring on the creep behavior of the holding ring at high temperature. On the basis of ensuring the accuracy of the calculation results, the calculation model is simplified. 3) based on the work of 1) and 2), the heat conduction in the holding ring has been calculated by using ANSYS software, and the heat conduction in the holding ring has been calculated. The distribution of temperature field and stress field in the physical process, such as convection heat transfer and radiation heat transfer, is obtained. The stress concentration region of the turbine holding ring is distributed in the two root grooves in front and back, and the maximum stress is in the front root trough, and the maximum initial stress is 125 MPA. 4) through the creep simulation calculation of 100, 000 hours, it is found that the stress field of the model has been changed. In the first 10,000 hours, the stress was reduced to less than 50%, the maximum stress point was transferred from the root groove of the front leaf to the root trough of the posterior lobe, the maximum elastic stress value decreased to 61 MPA, and the stress relaxation rate was in a decreasing trend. After 100000 hours, the maximum elastic stress decreased to 42 MPA; After creep, the angle of the root groove is changed, and the axial deformation of the static blade is caused. The maximum deformation of the blade is 1.24 mm, which is within the allowable range of creep.
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TK473

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