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Influence of inner reflux groove structure on flow characteristics of Roots pump |
XING Wenshuai1, ZHANG Fan1, ZHAO Feifei1, SONG Jialong1,ZHANG Jinfeng1, ZHU Xiumei2, TANG Xingpeng3 |
1. National Research Center of Pumps, Jiangsu University, Zhenjiang, Jiangsu 212013, China; 2. Jiangsu XCMG Engineering Machi-nery Research Institute Co., Ltd., Xuzhou, Jiangsu 221004, China; 3. Vacculex Vacuum Equipment(Zhejiang)Co., Ltd., Huzhou, Zhejiang 313100, China |
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Abstract The Roots pump exhibits distinct features such as high gas pressure at the exhaust port, low pressure in the basic volume, and significant airflow pulsation at the outlet due to gas reflux. The entire flow field of an MB7300 Roots pump was numerically calculating by using the Pumplinx software. The Q criterion vortex identification method, coupled with Tecplot software, was employed for a qualitative analysis of the flow field of the Roots pump vortex structure. The primary aim was to investigate the impact of the internal reflux tank′s angle and thickness on the outlet pressure pulsation and internal pulsations. The results indicate that the internal reflux tank structure has no significant effect on the inlet side′s flow pattern improvement. However, it can effectively diminish the exhaust pressure pulsation, flow pulsation, and vortex in the exhaust section. The study reveals that the effect is more pronounced with increased thickness. Nonetheless, excessive thickness and angle can result in a larger gap between the rotor and the housing, thereby exacerbating leakage and displacement reduction. The optimal angle and thickness of the internal reflux tank were determined to be 45° and 7.5 mm, respectively, which effectively reduced pressure and flow pulsation while minimizing flow loss. To maintain a non-negative outlet flow rate, the internal reflux tank′s size can range from an angle of 45° to 60° and a thickness of 7.5 mm to 10.0 mm. The findings of this study can serve as a foundation for research on airflow pulsation and shell structure design optimization of Roots pumps.
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Received: 09 August 2022
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