Noise analysis in the centrifugal pump based on vortex sound theory
This paper aims to analyze the sound and pseudo-sound generation mechanism and its corresponding control method in a centrifugal pump. The delayed detached eddy simulation and vortex sound theory are applied to calculate the flow and acoustic fields. The prediction results agree well with the experimental results. Based on the vorticity binary decomposition, the influence of vorticity and its components of rigid vorticity and shear on the sound and pseudo-sound fluctuation is discussed. The results show that the sound source is dominated by the shearing part rather than rigid vorticity. Sound and pseudo-sound pressure levels could be amplified when the fluctuation of vorticity and its components gets intense, but the pseudo-sound is less sensitive. The amplitude of sound pressure is threefold over the pseudo-sound in the spiral casing, while the pseudo-sound becomes higher than the sound at the outlet as the former decay slowly along the outlet tube. Increasing the volute tongue angle could reduce the fluctuation of vorticity and its components in the outlet tube, leading to a decrease in as much as 44% in sound pressure amplitude and 10% in pseudo-sound.Get more news about Vortex Centrifugal Fan,you can vist our website!
It’s of great significance for safe and reliable operation of fan to research on the stall characteristics of the airfoil. The 2D non-compressible Reynolds-Averaged Navier-Stokes equations was built to simulate the flow around the airfoil of G4-73No.8D centrifugal fan, a detailed numerical simulation under different angles has been carried out which based on the Realizable turbulence model with Fluent. The numerical results show that the smaller of the flow rate, the bigger incidence angle is, when the incidence angle is bigger than the critical incidence angle, the suction side stall appears. According simulation the airfoil stall appears when the incidence angle is -28°, with the increasing of the negative incidence angle, the separation point gradually moves to the leading edge. There is a strong vortex which locates at suction side =0.5,the alternating stress on the blade which caused by vortex will make the blade fatigue. If the incidence angle is less than -20°,there is no flow separation, therefore, to ensure the safe operation of the fan, the incidence angle should be less than -20°.
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