交错式扇贝阻尼密封动力特性研究

Dynamic Characteristics of Interlaced Scallop Damper Seals

建立交错式扇贝阻尼密封三维数值分析模型,基于动网格及多频椭圆涡动模型研究密封动力特性沿轴向分布规律,计算分析错开角度(α=0°、11.25°、22.5°、33.75°)与密封腔深度(h=2.8、3.3、3.8和4.3 mm)对密封动力特性的影响.结果表明:上游腔室(C1~C4)具有较大的正直接刚度和有效阻尼,对抑制转子涡动、提升系统稳定性的贡献相对较大.相对并列式(α=0°)结构,交错式扇贝阻尼密封流体周向速度较小、湍流耗散增加,系统稳定性提升,同时密封泄漏量降低.错开角度为33.75°时的有效阻尼约为0°时的111%~121%;错开角度为22.5°时的泄漏量相较于0°时约降低了2.11%.有效阻尼随密封腔深度减小而增大,密封腔深度为2.8 mm时的有效阻尼约为4.3 mm时的146%~211%;密封泄漏量随密封腔深度增大而降低,密封腔深度为4.3 mm时的泄漏量相较于2.8 mm时降低了约3.73%.

The three-dimensional numerical analysis model of an interlaced scallop damper seal was established. The dynamic characteristics in the axial direction was studied. Effects of the interlaced angle(α=0°,11.25°,22.5°,33.75°)and seal cavity depth(h=2.8 mm,3.3 mm,3.8 mm,4.3 mm) on the dynamic characteristics of the scallop damper seal were analyzed based on dynamic mesh method and multi-frequencies elliptic whirling model. Results showed that the upstream seal cavity(C1~C4) had a large positive direct stiffness and effective damping,which showed a relatively greater contribution to suppress the rotor whirling and improved the system stability. Compared with the parallel structure(α=0°),the interlaced scallop damper seal had lower circumferential velocity,higher turbulence dissipation,better system stability,and lower seal leakage flow rate. When the interlaced angle was 33.75°,the effective damping was about 111% to 121% of that at 0°. The leakage flow rate for an interlaced angle of 22.5° was about 2.11% lower than that at 0°. The effective damping increased with decreasing seal cavity depth. The effective damping of the seal with cavity depth of 2.8 mm was 146% to 211% that of 4.3 mm. The leakage flow rate of the scallop damper seal decreased with increasing seal cavity depth. The leakage flow rate for the seal cavity depth of 4.3 mm was reduced by about 3.73% compared with that of 2.8 mm.