Influences of dis-tuned tip clearance on the discrete aerodynamic noise in centrifugal compressor

With the purpose of decreasing the discrete aerodynamic noise in turbocharger compressor, the influences of dis-tuned impeller tip clearances on the aerodynamic noise are numerically and experimentally investigated. The dis-tuned tip clearance configuration is realized by ensuring either a bigger tip clearance size for main blades while a smaller one for splitter blades, or a smaller tip clearance size for main blades while a bigger one for splitter blades. The influences of dis-tuned tip clearance on centrifugal compressor performances are validated and results indicate that the dis-tuned tip clearance method used in current study has minor influences on compressor performances. Based on full unsteady CFD results, near field discrete aerodynamic noise analysis is performed on the tip clearance dis-tuned compressors, while far field aerodynamic noise is experimentally investigated. Both numerical and experimental results show that the dis-tuned tip clearance configurations have significant influences on compressor discrete aerodynamic noise, with maximum noise SPL decreased by 8 dB under the compressor operation points investigated in current research..