基于ANSYS的汽轮机低负荷工况相对胀差分析

研究汽轮机变工况,是机组轴系方案的选定、运转线选择及调节系统设计的依据。根据汽轮机转子及汽缸的几何模型的特点建立了转子及汽缸的有限元模型。利用数值分析的边界条件,运用ANSYS有限元分析软件,对汽轮机转子及汽缸空负荷工况下,不同排气温度时的相对胀差进行了数值模拟。将部分模拟值与实测值进行对比,发现相对胀差的计算值与实测值的误差在排汽温度为47,63,90℃时,分别为5.2%,0.74%,4.7%,发现该数值模拟可靠。进而,可以通过ANSYS模拟其他变工况的特性,向用户及运行部门提供机组特性曲线,使之熟悉机组的变工况特性。为合理地控制胀差提供了指导,并对优化设计提供了理论依据。

Analysis of Differential Expansion of Steam Turbine Under Working Mode of the Low Load Based on ANSYS

The research on changeable work situation of steam turbine is the foundation to choose shafting project and movement route and adjust system design.According to geometry model characteristic of shaft and cylinder of steam turbine,a finite element method model of shaft and cylinder was set up.Based on terminal conditions of numeric analysis,numeric analysis of the relative expanding difference of shaft and cylinder of steam turbine was made at the different temperatures in the no-load work condition by ANSYS.Comparing with the measuring value,the errors between computing value and measuring value of differential expansion are 5.2%,0.74%,4.7% at 47,63,90℃.The simulation value is credible.Thus,other changeable work characteristic can be simulated by ANSYS.Then,the characteristic curve can be offered to the users and running department that can know well the changing work characteristic.It gives a guide of controlling rationally differential expansion and a theory base of optimizing design.