Performance Improvements of a Centrifugal Pump with Different Impellers using Polymer Additive

In this study, the performance of a centrifugal pump is investigated by adding polyacrylamide (PAM) polymer over the working fluid which is tap water in this case. PAM is a long chain polymer that leads to reduce the wall shear stress and drag in a turbulent fluid. Three different blade profiles including radial, straight backward and circular backward have been examined. For this purpose, a centrifugal pump test rig consists of reservoir, pump-motor, volumetric measuring tank, pressure gauges, speed control, and motor dynamometer has been used. Different concentrations of PAM polymer solution are prepared in the range of 80-240 ppm of PAM. The results show that the maximum amount of relative efficiency is approximately 3% for the radial propeller, 13% for the straight backward propeller, and 18% for the circular backward which is occurs at 160 ppm of PAM. It is found that this increase is more pronounced in the case of circular backward impeller. Moreover, in the case of radial blade profile, it is observed that in spite of efficiency increase, the head decreases at low flow rate with adding PAM.