双尖槽干气密封特性对比研究

提出一种新型双尖槽端面密封，具体由两个开槽深度不同、径向长度相同的螺旋槽及1个圆弧槽组合而成. 建立了该双尖槽与燕尾螺旋槽端面密封的数学模型，并运用有限差分法进行了数值计算. 结果表明:在小间隙区域，双尖槽具有更大的开启力、泄漏量、刚度及刚漏比，且间隙越小，双尖槽较燕尾螺旋槽其端面的开启力、刚度及刚漏比差值越大；在间隙(h₀)小于3.0 μm区域，双尖槽开启力整体大于燕尾螺旋槽；在间隙小于6.0 μm区域，双尖槽气膜刚度整体大于燕尾螺旋槽；在间隙小于6.8 μm区域，双尖槽刚漏比整体大于燕尾螺旋槽；特别是在间隙为3.0~5.0 μm区域，双尖槽较10 μm和8 μm槽深燕尾螺旋槽刚度有显著增大，较5 μm槽深燕尾螺旋槽增幅也达到6%左右；在间隙约小于3.0 μm区域，双尖槽较燕尾螺旋槽的泄漏量值虽有所增大，但其值没超过泄漏量的设计值，密封基本性能指标合格. 故双尖槽在泄漏量不超标的情况下，具有更优的综合性能. 

A Comparative Research on the Characteristics of Dry Gas Seal with Double Pointed Grooves

A new type of Double Pointed Groove (DPG) seal face was proposed, which was composed of two spiral grooves with different groove depth and the same radial length and one circular arc groove. The mathematical model of the DPG and the Dovetail Spiral Groove (DSG) face seal was established, and the numerical calculation was carried out by using the finite difference method. In the small clearance area, the DPG had larger opening force, leakage, stiffness and ratio of stiffness to leakage, and the smaller the clearance, the greater the difference. When h₀<3.0 μm, the DPG had larger opening force; when h₀<6.0 μm, the film stiffness of the DPG was larger than that of the DSG; when h₀<6.8 μm, the DPG had larger stiffness leakage ratio. In the area with a clearance of 3.0~5.0 μm, the stiffness of DPG had a significant increase compared to the DSG with the depth of 10 μm and 8 μm. And the relative change (RC) was about 6% compared with the DSG of 5 μm. When h₀<3.0 μm, the leakage of the DPG was higher than that of the DSG, but the leakage value did not exceed the design value, and the basic sealing performance index was qualified. Therefore, the DPG had better comprehensive performance under the condition that the leakage did not exceed the standard.