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采用TVD格式求解非定常可压缩Navier－Stokes方程，数值研究恒定压比作用下不同空腔深宽比H／W和倾向6的迷宫密封内部流动。计算了3种矩形空腔模型（H／W=0．1，0．3，0．5，θ=0°）和两种倾斜空腔模型（θ=45°，-45°，H／W=0．5）的流动，结果展示了后倾空腔模型（θ=-45°）的稳态流动结构和其余4种模型的流动振荡及出口泄漏量的波动。通过分析涡运动与涡合并、分离泡生成与迁移、射流弯曲和冲击空腔前壁及其相关效应等流动现象的内在联系，揭示了局部不稳定效应增加能耗减小泄漏的作用机制。计算表明，矩形空腔模型中H／W=0．3的不稳定效应最强，前倾空腔比矩形和后倾空腔具有更强的不稳定效应；密封效率的变化趋势与此相同，与实验结果相符。最后，提出总体流动结构基本稳定和局部流动结构不稳定的迷宫密封流体动力学机理，指出不稳定效应的强弱差异是造成不同结构参数密封效果优劣的重要原因。
The unsteady compressible Navier-Stokes equations are solved by the TVD scheme and the labyrinth internal flow with different cavity aspect ratio H / W and dip 6 under constant pressure ratio is investigated numerically. Three rectangular cavity models (H / W = 0.1, 0.3, 0.5, θ = 0 °) and two inclined cavity models (θ = 45 °, -45 °, H / W = 0.5). The results show the steady-state flow structure of the backward cavity model (θ = -45 °) and the fluctuation of the flow oscillation and the outlet leakage of the remaining four models. By analyzing the intrinsic relations between eddy motion and vortex merger, separation bubble generation and migration, jet bending and impact on the front wall of the cavity and its related effects, the mechanism of local instability with increased energy consumption and leakage reduction is revealed. The calculation shows that the instability effect of H / W = 0.3 is the strongest in rectangular cavity model, and the instability effect of forward cavity is stronger than rectangular and backward cavity. The changing trend of sealing efficiency is the same, In line with the experimental results. Finally, the mechanism of labyrinth seal hydrodynamics is proposed, which shows that the overall flow structure is basically stable and the local flow structure is unstable. It is pointed out that the difference between the strengths and weaknesses of the instability effect is the important reason that causes the sealing effect of different structural parameters.