'Periodica Polytechnica Budapest University of Technology and Economics'
Abstract
Comparative computational investigation has been carried out on
two axial flow pump rotors having identical basic geometrical and flow rate
parameters but differing in the design methods. The two rotors were designed
for free vortex (FV) and non-free vortex (NFV) operation. The global as well as
pitchwise-averaged and pitchwise resolved blade passage flow characteristics
were investigated in detail. It has been concluded that NFV design is an
effectual method for increase of specific performance but the increased risk of
cavitation requires careful blade optimisation. It was found that the design
blade circulation must kept constant near the hub in order to diminish the risk
of corner stall. Furthermore, it has been anticipated that for the NFV rotor
the efficiency drops more intensely with increase of tip clearance and the
noise level may be lower than for the FV rotor
