Flow Characteristics of a Centrifugal Pump with Different Impeller Trimming Methods

Influences of different impeller trimming methods on flow characteristics of a centrifugal pump have been studied numerically and experimentally in this research. Different cases of trimmed impellers include straight trimmed impeller with and without remained shrouds, oblique trimmed impeller, triangular trimmed impeller, semi-circular trimmed impeller and polygon-shaped trimmed impeller. Verification of computational results has been investigated through comparison of experimental and numerical data as maximum deviation of 5.4 per cent has been observed. Results revealed that impeller trimming method has profound impact on the centrifugal pump performance as the highest head value has been achieved by employing the impeller with polygon-shaped trimmed shrouds at all flow rates, which is by 5 per cent higher than that of the conventional trimmed impellers (straight trimmed ones). Furthermore, it is also seen that the efficiency of polygon-shaped trimmed impeller was reduced by 3.6 per cent at BEP (Best Efficiency Point).