﻿ 多场耦合下燃气轮机涡轮盘的寿命预估
 舰船科学技术  2018, Vol. 40 Issue (7): 85-88 PDF

Multi-field coupled life prediction of gas turbine disks
HUANG Jin-e
Institute of Surface Combat System, Naval Research Acdemy, Beijing 100161, China
Abstract: In order to estimate the life expectancy of gas turbine disks under the influence of centrifugal loads and temperature gradients, the finite element model of the gas turbine disk was established and calculated firstly. Then find out the dangerous part of the turbine disk fatigue fracture, and use S-N curves to calculate the fatigue life of the site. The study can provide references for the subsequent use and maintenance of gas turbine, and it can also serve as a reference for the life prediction of the same type of turbine disks.
Key words: finite element model     thermal elastoplastic stress calculation     S-N curves     life prediction
0 引　言

1 涡轮盘的应力分析 1.1 涡轮盘的有限元建模

 图 1 涡轮盘的实体模型 Fig. 1 Solid model of turbine disk
1.2 热弹塑性应力计算

 \begin{aligned}{F_C} = & mR{\omega ^2} = 437.67 \times {10^{ - 3}} \times 357.36 \times {10^{ - 3}} \times \\& {\left( {1 \; 513.48} \right)^2} = 358 \; 266.41 \; {\rm N},\end{aligned}

 $\frac{{{F_C}\sin 50^\circ }}{S} = 465.402 \; 7 \; {\rm{MPa}}{\text{。}}$

 图 2 涡轮盘的温度场 Fig. 2 The temperature field of a turbine disk

 图 3 涡轮盘的热弹性计算应力分布 Fig. 3 The thermal elastic calculation of the stress distribution of a turbine disk

 图 4 涡轮盘的热弹性计算应力分布 Fig. 4 The thermal elastic calculation of the stress distribution of a turbine disk

2 基于S-N曲线的涡轮盘寿命预估

 $\begin{split}Y = & A + {B_1} \cdot X + {B_2} \cdot {X^2} + {B_3} \cdot {X^3} + \\& {B_4} \cdot {X^4} + {B_5} \cdot {X^5} + {B_6} \cdot {X^6} + {B_7} \cdot {X^7}{\text{。}}\end{split}$ (1)

S-N曲线上的8个点及其拟合曲线如图5所示。

 $X = {\sigma _{eq}}{\text{，}}$

 ${\sigma _{eq}} = \frac{{{\sigma _{\max }} - {\sigma _{\min }}}}{{1 - \displaystyle\frac{{1.1}}{{1060}}{\sigma _{\min }}}}{\text{。}}$
 图 5 GH4169材料的S-N曲线 Fig. 5 S-N curve of GH4169 material

 \begin{aligned}& \frac{1}{{{N_P}}}{\rm{ = }}\frac{1}{{39 \; 170}}{\rm{ + }}\frac{{0.05}}{{42 \; 180}}{\rm{ + }}\frac{2}{{220 \; 300}}{\rm{ + }}\frac{{7.2}}{{578 \; 100}} + \\& \frac{{0.1}}{{3 \; 186 \; 000}} + \frac{{3.2}}{{224 \; 400 \; 000}} + \frac{{6.85}}{{7 \; 272 \; 000}} + \frac{{0.2}}{{682 \; 400 \; 000}}\\& {N_P}{\rm{ = 17 \; 444}}\;{\text{次循环}}{\text{。}}\end{aligned}
3 结　语

1）通过对涡轮盘进行有限元计算，不难发现，当涡轮盘在设计转速下运行时，其中心孔部位出现了应力屈服，因此应当被视为疲劳断裂的危险关键部位进行寿命预估。

2）利用S-N曲线法成功预估了涡轮盘的疲劳循环次数为17 444次循环。

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