The customer, one of the world’s largest pump manufacturers, asked ADT to design an inducer to fit in one of their products, a multi-stage centrifugal pump.
A designer needs to consider the suction performance of the first stage to make sure that the pump can sustain low inlet
pressure without suffering with cavitation and therefore pressure drops vibration and damage. One solution to improve the suction performance is to use an inducer in front of the first stage to raise the pressure to a level where the impeller will operate normally.
First Stage
The first phase of the project was the analysis of the existing impeller and inlet component. The analysis allowed for extracting the flow field at the operating point and validating the model used for the analysis of the inducer in the design phase.
Fig.1. Blade loading and static pressure from inviscid flow field.
Inducer Design
The design of the inducer was done using the 3D Inverse Design software, TURBOdesign1. The inlet condition was simplified (linear distribution) from the flow field data extracted from the analysis phase.
Conclusion
Eventually, an inducer design was created that could fit the geometrical constraints, match the impeller design and
improve the suction performance of the stage. A reduction of the NPSH3% was observed and the inducer halved the
NPSH3% of the first impeller stage at design point.