Numerical Simulation for Effects of Inducer Geometrical Variations on a Centrifugal Pump Hydraulic Performance

Using inducers in order avoiding pressure reduction at the centrifugal pump impeller inlet and consequently increasing pump performance at high suction speeds are important in many applications. The inducer which is an axial pump with lower number blades than impeller’s (usually 3 or 4), located on the upstream impeller and rotates with the same rotational speed and direction as the pump. In this research, changing inducer design parameters such as the blade pitch and the length to the diameter ratio on its and pump hydraulic performance is investigated, numerically. The results show that using inducer and changing its blade pitch ratio from 0.24 to 0.48, causes average pressure ratio increasing from %10 up to %34 at the pump impeller inlet. Unlike the pitch ratio changing effects, increasing the length to blade diameter ratio from 7/12 to 16/12 show a fairly constant average pressure ratio increasing up to %23. For the large pitch ratio, pump impeller induced head; decreases for low flow rate. Meanwhile, decreasing pitch ratio in high flow rate causes flow counter rotation at the pump impeller inlet that increases the pump impeller head.