Optimization of Hole Configuration Parameters for Design of Damper Seals with Square-Hole Pattern

研究了定子表面孔形参数（孔截面积Sd、孔总数Nd、孔总截面积一定时Nd和Sd的组合）对液体环形密封轴向泄漏流量Q、动特性系数和周频比WFR的影响。这里，WFR对应于转子旋转速度的上限，在该上限处，密封间隙中的动态流体力增强旋转运动，并且由于缩小旋转速度的不稳定范围，WFR的较小值是期望的。结果表明，增大Nd和采用大Nd与小Sd的组合方式，Q值和WFR值均降低，且减小了进口旋流速度对WFR的定量影响。因此，从减少泄漏流量和抑制转子涡动运动的角度来看，这些孔图案有助于提高泵的效率和稳定裕度。

The axial leakage flow rate Q, the dynamic coefficients and the whirl-frequency ratio WFR of liquid annular seals are investigated for the three hole-pattern parameters formed in the stator surface: the cross-sectional area Sd of hole, total number Nd of holes, combinations of Nd and Sd under a constant total cross-sectional area of holes. Here, WFR corresponds to an upper limit of rotor whirling velocity at which the dynamic fluid force in the seal clearance enhances the whirling motion and smaller value of WFR is desirable due to narrowing the instability range of whirling velocity. The results show that increasing Nd and using the combinations of large Nd and small Sd yield a lower Q and smaller WFR, and reduce the quantitative effect of the inlet swirl velocity on WFR. Hence, these hole-patterns contribute to improving the efficiency and stability margin of pumps from the viewpoint of reducing the leakage flow rate and suppressing the rotor whirling motion.