engleski

Experimental Research on Affinity Law for Trimmed Impellers

Abstract. Impeller trimming is a common practice performed by pump manufacturers and users when it is necessary to adjust the centrifugal pump head and flow to the actual needs. The trimmed pump is not strictly similar to the initial pump because only a few parameters are modified, while all the others remain unchanged. In spite of this, the assumption of valid similarity was made here and examined through a series of experiments. A centrifugal pump impeller of low specific speed (nsp = 19, 745 r.p.m. m0.75 s-0.5) was trimmed and tested successively. For this particular pump, the influence of disregarded similarity can be estimated to  3, 94% for the pump head and to  5, 24% for the power, both with a 95% statistical certainty.

Hydraulic machinery; impeller trimming; afinity law

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