热和离心力耦合作用下燃气涡轮叶顶间隙变化

Blade tip clearance of gas turbine under influence of centrifugal and heat

高压涡轮叶顶间隙的变化对燃气轮机的功率、效率和寿命有着重要影响。为了准确掌握不同工况下叶顶间隙的变化,建立了在热和离心力作用下燃气轮机叶顶间隙变化模型,计算了不同工况下热和离心力作用下的叶片、轮盘径向变形及热作用下机匣的膨胀变形,进而得到了叶顶间隙的变化规律。结果表明:热和离心力变化是间隙变化的两个主要因素,快速加减速对间隙的影响最大;加速过程中,间隙急剧减小,减速过程中,间隙增加。

Changes in the HPT blade tip clearance have a significant effect on the power,efficiency and service life of the gas turbine.In order to control the tip clearance,a model was established for the tip clearance variation influenced by centrifugal and heat.The effects of centrifugal and heat on the radial elongations of rotor and the thermal expansibility of the shroud at different states were qualitatively analyzed and quantitatively computed.And the regularity of variations in clearance was obtained.The results show that the thermal and centrifugal changes are the two main reasons for the changes in clearance.Fast acceleration and deceleration have the greatest influence on the clearance.The clearance decreases rapidly in acceleration while it increases sharply in deceleration.