As well known, the complete similarity affinity laws are derived from the dimensional analysis techniqe of seven parameters that describe the pump performance; density, viscosity, D, speed, Q, h, and P . The analysis is based on a fixed length scale ratio that the conditions of the machines are geometrically similar. The complete affinity laws were developed which provide the three famous basic nondimentional coefficients, CQ, Ch, and CP. Here, one can change speed, size, or both, and predict the new performance parameters while keeping the pump efficiency mostly fixed according to the system behavior. However, to reduce costs pump casings are designed to accommodate a number of different impellers while keeping the same shaft. This leads to incomplete similarity as we don’t have a fixed length scale ratio for all pump components. Hence, the nondimentional coefficients are somehow expected to be changed.
HEAD - CAPACITY characteristic curves . The entire aspect of designing of a centrifugal pump along with choice of procurement .
The pump performance parameters, flow rate, head, and power, will change with changing impeller diameter within the same casing. The flow and head coefficients have the same form as that for the complete similarity. However, the power coefficient should be changed according to the practice to become depending on D3 instead of D5.
HEAD - CAPACITY characteristic curves . The entire aspect of designing of a centrifugal pump along with choice of procurement .
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