Pump Performance Related to Different Impeller Exit Blade Shapes

Abstract

This paper reports on an experiment in a centrifugal pump with several different impeller exit blade shapes. A pump is usually designed to a specification associated with the maximum impeller diameter. Therefore, when higher head: H or capacity: Q is demanded, a larger impeller diameter will be required.
On the other hand, in order to make a slight improvement in head-capacity curve, without changing the impeller diameter, underfiling could be used. Namely the metal removal of a section of the blade at suction side of impeller exits, is a method to achieve modest gain in head. Inversely to the underfiling of blade exits, another method to control pump performance is the formation of flaps at impeller blade exits.
Moreover, an analytical method of predicting the pump performance related to the introduction of a flap at the trailing edge of impeller blade is presented.