Centrifugal pump impeller cutting

This post was last edited by Higee on 2017-6-9 11:42 This question is still about whether the working point of the centrifugal pump can be determined based on the law of proportion (the cutting law is still the law of proportion). According to the first question, we can know that the characteristic curve of the pipeline is H=5+1.66e-3Q^2, the working point Q=90m3/h, H=18.45m. Now the flow rate is required to be reduced by 20%, that is, Q'=72m3/h. Substitute into the pipeline characteristic curve to get the required pressure head H'=13.6m When the impeller is cut, the characteristic curve of the centrifugal pump changes in translation. The specific curve equation can be derived according to the cutting law. The results are given directly here.: He=22.2×(impeller diameter after cutting/impeller diameter after cutting)^2-4.63e-4Q^2 Substituting Q'=72m3/h, H'=13.6m into the above curve formula, we can get (impeller diameter after cutting/impeller diameter after cutting)=0.849 Therefore, the cutting amount is 15.1%, and the power Ne=ρgH'Q'=2.67kW. Select C