Experimental Study of the Flow in the Suction Pipe of a Centrifugal Pump at Partial Flow Rates in Unsteady Conditions

摘要

The operational range and the performances of pumps are limited by the occurrence of backflow and pre-rotation in the suction pipe as the flow rate is reduced. This paper presents the study of static pressure measurements and visualizations in the suction pipe, near the inlet of a centrifugal pump, at partial flow rates, in steady conditions, and during a fast start up of the pump. The tests were carried out in water on the DERAP~© test loop of the ENSAM Lille laboratory. Standard methods allowed to determine the recirculation critical flow rate. A visualization method showed that the axial extent of the recirculation and the prerotation with the flow rate is considerably reduced during a fast start up compared to steady conditions.