Rotating fluids are well-known to be susceptible to waves. This has received much attention from the geophysics, oceanographic and atmospheric research communities. Inertial waves, which are driven by restoring forces, for example the Coriolis force, have been detected in the research fields mentioned above. This paper investigates inertial waves in turbine rim seal flows in turbomachinery. These are associated with the large-scale unsteady flow structures having distinct frequencies, unrelated to the main annulus blading, identified in many experimental and numerical studies. These unsteady flow structures have been shown in some cases to reduce sealing effectiveness and are difficult to predict with conventional steady Reynolds-averaged Navier-Stokes (RANS) approaches. Improved understanding of the underlying flow mechanisms and how these could be controlled is needed to improve the efficiency and stability of gas turbines. This study presents large-eddy simulations for three rim seal configurations – chute, axial and radial rim seals – representative of those used in gas turbines. Evidence of inertial waves is shown in the axial and chute seals, with characteristic wave frequencies limited within the threshold for inertial waves given by classic linear theory (i.e. $|f^{*}/f_{r}el|\le 2$), and instantaneous flow fields showing helical characteristics. The radial seal, which limits the radial fluid motion with the seal geometry, restricts the Coriolis force and suppresses the inertial wave.

中文翻译：

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涡轮缘密封中的惯性波

众所周知，旋转流体容易受到波浪的影响。这已经引起了地球物理学，海洋学和大气研究界的广泛关注。在上述研究领域中已经检测到由恢复力例如科里奥利力驱动的惯性波。本文研究了涡轮机械中轮辋密封流动中的惯性波。这些与在许多实验和数值研究中确定的，具有不同频率的大规模非稳态流动结构有关，这些频率与主环叶片无关。这些不稳定的流动结构在某些情况下已显示出降低密封效果的效果，并且难以通过常规的稳定雷诺平均Navier-Stokes（RANS）方法进行预测。为了提高燃气轮机的效率和稳定性，需要更好地了解基本的流动机制以及如何控制这些流动机制。这项研究提出了三种轮圈密封结构（溜槽，轴向和径向轮辋密封）的大涡模拟，代表了燃气轮机中使用的那些。轴向和斜道密封中显示了惯性波的证据，特征波频率限制在经典线性理论给出的惯性波阈值之内（即 $|F^{*}/F_{\mathrm{[R}}Ë升|\le 2$）以及显示螺旋特性的瞬时流场。径向密封件通过密封件的几何形状限制了径向流体的运动，从而限制了科里奥利力并抑制了惯性波。