为了探究日照温差下明钢管变位特性,基于某水电站典型管段明钢管,运用ANSYS软件,建立三维有限元模型,研究了检修时在日照两侧温差下明钢管的偏移及受力,进一步分析了在此偏移不能恢复时充水运行后的管段位移、受力情况。结果表明:在不均匀温差引起的管段变形的基础上充水运行,管段更显著地向低温侧偏移,管段弯曲加剧,运行水头越高则管段受不均匀温差影响越大;限位挡板缝隙越大,则支座、限位挡板受力越小,但是限位挡板对管段的约束作用越弱;管段变位以及支座、限位挡板受力较大的部位均出现在靠近伸缩节的支墩处,可以考虑在此处缩小支墩间距以加强管段约束、缓解结构受力;为防止不均匀温差下管段从支座上脱落,有必要适当增大限位挡板尺寸。

The deformation and stress condition of exposed steel penstock under non-uniform temperature due to sunshine during overhaul are analyzed through ANSYS which is based on a typical part of penstock in a hydropower station. Further simulations on the deformed penstock applied with internal water pressure are also carried out. Results indicate that when bearing internal water pressure, the deformed exposed penstock induced from the former non-uniform temperature shows obvious increasing lateral displacement to the cold side and bending in horizontal plane. The temperature effects are more obvious if the pressure is higher. A bigger gap between supports and lateral dampers brings about lower reaction around supports and constraint plates while weakens the restraint of dampers to penstock. In order to strengthen the restriction to penstock and relieve reaction, it is recommended to reduce the distance between pier foundations around bellows expansion joint because deformation and reaction here are enormous. Meanwhile, enlarging the lateral damper appropriately is necessary to avoid penstock sliding away from supports under the non-uniform temperature.