Numerical Simulation of the Working Process in the Twin Screw Vacuum Pump

10th International Conference on Compressors and their Systems

Lu, Yang^1 ; Fu, Yu^2 ; Guo, Bei^1 ; Fu, Lijuan^1 ; Zhang, Qingqing^1 ; Chen, Xiaole^1

Xi'An Jiaotong University, Xi'an, China^1

Xi'An Aerospace Propulsion Institure, Xi'an, China^2

关键词: Compact structures;    Flow coefficients;    Geometric feature;    Geometric modeling;    High reliability;    Indicator diagram;    Isentropic process;    Rotational speed;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/232/1/012027/pdf
DOI  :  10.1088/1757-899X/232/1/012027

来源: IOP

【 摘 要 】

Twin screw vacuum pumps inherit the advantages of screw machinery, such as high reliability, stable medium conveying, small vibration, simple and compact structures, convenient operation, etc, which have been widely used in petrochemical and air industry. On the basis of previous studies, this study analyzed the geometric features of variable pitch of the twin screw vacuum pump such as the sealing line, the meshing line and the volume between teeth. The mathematical model of numerical simulation of the twin screw vacuum pump was established. The leakage paths of the working volume including the sealing line and the addendum arc were comprehensively considered. The corresponding simplified geometric model of leakage flow was built up for different leak paths and the flow coefficients were calculated. The flow coefficient value range of different leak paths was given. The results showed that the flow coefficient of different leak paths can be taken as constant value for the studied geometry. The analysis of recorded indicator diagrams showed that the increasing rotational speed can dramatically decrease the exhaust pressure and the lower rotational speed can lead to over-compression. The pressure of the isentropic process which was affected by leakage was higher than the theoretical process.