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新型非对称变间隙涡旋齿型线设计及内部流动特性实验研究

Design of Novel Asymmetric Variable-Clearance Spiral Tooth Profile and Experimental Investigation of Internal Flow Characteristics

  • 摘要: 现有非对称式涡旋结构存在工作腔压力不平衡以及和排气口压力波动的问题,在此背景下开展开涡旋真空泵型线的研究,将对称式涡旋型线里中的组合型线应用到非对称涡旋型线中,构建出新型非对称涡旋型,提出解决啮合难题的非对称式圆弧修正法来解决啮合难题,设计非对称变间隙涡旋齿型线曲线方程,并提出了非对称式涡旋真空泵型线中为了保证涡旋机械能够高效稳定地运行,两组工作腔压力不等的情况可以借助梯度变化的啮合间隙来得到改善。确定非对称涡旋真空泵的基本参数,计算各个腔的容积以及内容积比,分析工作腔面积的变化规律,同时分析偏置系数对齿隙的影响,实现性能优化。本研究借助新型非对称型线设计并引入偏置系数j形成变间隙啮合结构,使得涡旋真空泵内流场性能得到了明显改善,模拟结果显示,该设计使压缩腔压力平衡比从1:0.767提升到了1:0.992,当偏置系数j=0.2时,压力脉动率降低了38.5%,流量脉动率下降了18.2%。实验验证说明,在20 kPa压差的情况下,新型泵的平均流量达到10.5 m3/h,压力脉动范围仅仅0~1.9 kPa,均优于传统泵,充分呈现出其在抑制脉动以及提升流动稳定性方面的优势。

     

    Abstract: Existing asymmetric vortex structures suffer from issues such as pressure imbalance in the working chamber and pressure fluctuations at the exhaust port. Against this backdrop, research on vortex vacuum pump profile lines was conducted. By applying composite profile lines from symmetric vortex profiles to asymmetric vortex profiles, a novel asymmetric vortex profile was constructed. An asymmetric arc modification method is proposed to resolve meshing challenges. The curve equation for an asymmetric variable-clearance scroll tooth profile is designed. To ensure efficient and stable operation of the scroll mechanism, the pressure imbalance between the two working chambers can be mitigated through a gradient-varying meshing clearance. The fundamental parameters of the asymmetric vortex vacuum pump were determined, the volumes and internal volume ratios of each chamber were calculated, and the variation patterns of the working chamber area were analyzed. Concurrently, the influence of the offset coefficient on backlash was examined to achieve performance optimization. This study employs a novel asymmetric profile design incorporating an offset coefficient j to form a variable clearance meshing structure, significantly improving the flow field performance within the vortex vacuum pump. Simulation results demonstrate that this design increases the compression chamber pressure balance ratio from 1:0.767 to 1:0.992. When j=0.2, the pressure pulsation rate decreases by 38.5%, and the flow pulsation rate decreases by 18.2%. Experimental validation demonstrates that under a 20 kPa pressure differential, the new pump achieves an average flow rate of 10.5 m3/h with a pressure pulsation range of only 0−1.9 kPa, outperforming conventional pumps and fully showcasing its advantages in suppressing pulsation and enhancing flow stability.

     

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