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.