Numerical Simulation And Optimization Design Of VSV300 Rotary Vane Vacuum Pump On Exhaust And Mechniacl Vibration Noise

With the widespread applications of the rotary vane pump, customers are raising increasing demands on vibration and noise of the rotary vane pump, making vibration and noise reduction of rotary vane pump a top priority. In this paper, VSV300 rotary vane vacuum pump of Zhejiang Value Mechanical & Electrical Products Co., Ltd is studied. The aerodynamic noise during exhaust, vibration noise of restrictor board and oil tank are simulated by fluid-structure coupling techniques, acoustics finite element method, acoustics boundary element method and virtual prototyping technology, getting all kinds of noise-related characteristics and optimizing the design for larger aerodynamic noise.For the characteristics of VSV300 rotary vane pump, volumetric element, inlet pressure, exhaust velocity variation with angle of the rotor for rotary vane pump are established, which lay the theoretical foundation for the full text; by making two-way fluid-structure coupling with software of CFX and transient structure model of Workbench for aerodynamic model and restrictor board, their pressure and velocity contours are got.Acoustics finite element method with software of Virtual.Lab Acoustics is used to simulate aerodynamic noise during exhaust process, obtaining the curve of sound power level regarding to frequency. It is observed that the higher noise is in low-frequency region and high-frequency region exist more curve cusp. In addition, five points of noise, of which the contribution to noise is larger in amount, are established on the aerodynamic model to analysis noise characteristics, it is observed that sound pressure level is high in low-frequency region and there are large differences in sound pressure level at high frequency:at point 1 (anti-back oil hole), sound pressure level in high-frequency region is relatively large and the values of sound pressure in almost the entire frequency range are more than 75dB; at point 3 (pump chamber), there is relatively more curve cusp and sound pressure level is high, which indicates that it generates sharper noise; at point 2 (exhaust hole), there is a generally tendency of decrease after the first increase; there is a relatively similar sound pressure distribution at point 4 (tank baffles) and point 5, both being relatively low.Vibration noise of restrictor board is studied with acoustic boundary element method, which finds that there is little vibration noise of restrictor board and it’s sound power level is 20dB or less over the entire frequency range according to the sound power level of frequency response curve. Moreover, vibration noise of the board end portion is higher than that of the root by comparison.Vibration noise of oil tank is studied with acoustic boundary element method. Before the noise study, virtual prototype model built is simulated by the software of ADAMS, and excitation force of oil tank is obtained. Then, the distribution feature of oil tank noise and vibration displacement is got by the acoustic boundary element method. It is observed that vibration displacement is larger in the low-frequency region and smaller in the high-frequency region. By observing the sound power level responding to frequency curve of fuel tank, the trend of noise distribution is found that the amplitude of noise substantially increases after the first reduction. This is mainly due to the fact that vibration noise is associated with the amplitude and frequency and there is larger amplitude in low-frequency region, higher frequency in high-frequency region.Finally, two solutions are proposed just for passage way in portion of larger aerodynamic noise. These programs just like original model of VSV300, original model without anti-back oil hole, the original model without anti-back oil hole improved by the first solution, the original model with anti-back oil hole improved by the second solution, the original model with anti-back oil hole improved by the first solution are compared. It is found that two solutions can reduce noise significantly, but each has pros and cons, which requires to select optimal improvement according to actual working condition. Besides, Size optimization is performed on anti-oil hole. By the comparison and simulation of diameter ranging from 6mm,6.5 mm,7.0 mm to 7.5 mm, the reduction effect of noise is the best when the diameter of anti-back oil hole is 7mm.