Rated flow centrifugal pump hydraulic efficiency generally 0.8 to 0.9. mechanical loss. And the bearing friction loss, seal, etc. of high speed rotating mechanical friction between the impeller and the liquid called mechanical losses caused.mechanical efficiency is generally 0.96 to 0.99.
Centrifugal Pump incurs head loss due to friction. The friction is caused by the fluid changing direction when travelling through the pump and by the clearances within the pump. These losses vary with both head and flow.
ANALYSIS OF LOSSES IN CENTRIFUGAL PUMPS WITH LOW SPECIFIC SPEED WITH SMOOTH AND ROUGH WALLS K. Juckelandt S. Bleeck F. H. Wurm University of Rostock, Faculty of Mechanical Engineering and Marine Technology, Institute of Turbomachines, Rostock, Germany, [email protected] rostock.de ABSTRACT
The kinds of loss of centrifugal pumps can be differentiated in internal losses and external or mechanical losses. The internal loss is hydraulic losses or blade losses by friction, variations of the effective area or changes of direction losses of quantity at the sealing places between the impeller and housing at the rotary shaft seals.