ISSN   1004-0595

CN  62-1224/O4

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仿特斯拉阀结构新型槽端面干气密封的数值研究

Numerical Study on a New Tesla Valve Structure Dry Gas Seal

  • 摘要: 基于特斯拉阀结构的单向导通特性,提出一种集聚点更多和高压区域面积更大的新型(特斯拉阀型)干气密封槽型结构,该结构可获得比经典对数螺旋槽型更佳的密封效果. 通过建立特斯拉阀密封槽型的几何模型和数学模型,采用Fluent软件对不同几何参数和工况参数的密封性能进行系统数值仿真,获得密封开启力、气膜刚度和泄漏量等稳态性性能参数及瞬态膜压波动幅值方差. 分析了主阀道、支阀道和阀槽半径等参数对密封性能的影响规律,对比研究对数螺旋槽与特斯拉阀槽型在不同工况条件下的性能特性. 结果表明:相较于经典对数螺旋槽,同一工况下的特斯拉阀槽型具有更佳的开启力和刚度特性,尤其在高速、高压、小膜厚和大槽深时的开启力提升效果更加显著;在干气密封气膜稳定运行区间(h=3~6 μm),特斯拉阀槽型的气膜刚度较螺旋槽提升近20%;在高转速时(N>30000 r/min),特斯拉阀槽型的稳定性更好,且具有更小的压力波动.

     

    Abstract: Research into the design of dry gas seal face groove patterns has been a hot issue in this field, and efficient dynamic pressure groove patterns are essential for the stable operation of dry gas seals. This paper proposed a new (Tesla valve type) dry gas sealing groove structure with more gathering points and a larger high pressure area based on the single-guide characteristics of the Tesla valve structure, and found through systematic research that this groove can obtain better sealing results than the classical logarithmic spiral groove. Based on the backflow blockage effect of the Tesla valve structure, and with reference to the winged barrier geometry of the Tesla valve structure, a geometric and mathematical model of the Tesla valve seal groove type was developed. On the basis of the mesh-independent analysis, a systematic numerical simulation of the seal performance with different geometrical and operating parameters was carried out using Fluent software to obtain the steady's steady-state performance parameters, such as seal opening force, air film stiffness, leakage rate and the variance of transient film pressure fluctuation amplitude. The results showed that the maximum opening force of the Tesla valve groove type was slightly less than that of the classical logarithmic spiral groove under the same operating conditions, but the Tesla valve groove type had more than one high pressure area point and the high pressure area was significantly larger than that of the classical logarithmic spiral groove. Compared to the classic logarithmic spiral groove, the Tesla valve groove type had better opening force and stiffness characteristics under the same operating conditions, especially at high rotational speed, high pressures and small film thicknesses with large groove depths. The main valve channel width Bm, the branch valve channel width Bt and the valve groove radius Rv had a large impact on the opening force and leakage rate of the Tesla valve groove type, taking into account the opening force and leakage rate, the best choice of the three intervals were: Bm=4~6 mm, Bt=1.7~2.1 mm, Rv=22.5~32.5 mm. The Tesla valve groove type had almost 20% higher stiffness than the spiral groove in the stable operating range of the dry gas seal gas film (h=3~6 μm), and at high rotational speed (N>30000 r/min), the Tesla valve groove type was more stable and has smaller pressure fluctuations. Finally, based on the Taguchi design and multi-parameter systematic analysis with Minitab software, it was concluded that the order of influence of each factor on the sealing opening force was medium pressure>film thickness>groove depth>rotational speed>branch valve channel>main valve channel. The order of influence of each factor on the sealing leakage rate was medium pressure>film thickness>rotational speed>groove depth>main valve channel>branch valve channel. The main difference was the different weights of film thickness, rotational speed, main valve channel and branch valve channel.

     

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