燃气轮机高压涡轮叶顶间隙变化规律的有限元分析

高压涡轮叶顶间隙会直接影响到燃气轮机的功率、效率、油耗和寿命。利用有限元等软件,建立了叶片、轮盘和机匣外环的实物模型;通过热结构耦合分析,计算得到各自在温度场和离心力场作用下的径向位移,进而得到叶顶间隙变化规律,并进行了分析。计算结果表明：温度场变化是引起叶片和轮盘径向变形的主要因素;离心力对轮盘径向变形的作用比对叶片径向变形的作用要显著得多;热和离心力变化是间隙变化的两个主要因素;叶片、轮盘和机匣的热响应不一致以及离心力对转子的拉伸作用导致其径向膨胀变形不匹配,进而引起间隙变化;快速增减速度对间隙的影响最为明显。

The Finite Element Analysis for HPT Blade Tip Clearance Variation of Gas Turbine

The blade tip clearance variation of the high pressure turbine（HPT） has significant effect on the power,the efficiency and the service cycle of gas turbine.The finite element models of the blade,the disk and the shroud were built.The radial displacements were calculated by the thermal structural coupling method.The regulation of the blade tip clearance variation at the practical working states of the turbine was also analyzed.The results show that the temperature dominates the displacements of blade and disk.And the centrifugal force has an extending effect on the rotor than that of the blade.The radial displacements of them are not matching,thus lead to clearance changes.The thermal and the centrifugal force are the two major factors for the variation of tip clearance which was induced by the disharmony of radial displacements.Rapid accelerating and decelerating has the most significant effect on the clearance.