Computational Study on the Effect of Blade Cutback on the Performance of the Centrifugal Compressor

Abstract

Minimizing the energy losses associated with diffusion and also increasing the stable operating ranges of the diffusion systems necessitates developing non-conventional diffuser designs. Rotating vaneless diffusers is one such concept, in which a particular type, forced rotating vaneless diffuser, the diffuser is integral with impeller and rotates at the same speed as the impeller, is obtained by blade cutback, which involves blade trimming but leaving the impeller disks as it is. In this paper, the shrouded impeller with blade cutback by 5% to its vane length by which it introduces a rotating vaneless diffuser in between and a conventional shrouded impeller, both with stationary vanless diffuser are analysed on flow diffusion and performance aspects. The matching peak efficiency is achieved at design flow coefficient for both SVD and BCB 05 and slightly lesser efficiencies at off-design flow coefficients for BCB 05. The performance characteristics of BCB 05 are lesser in terms of energy coefficient, specific work, as well as static pressure rise.