Abstract
Abstract
In the current research, an experimental and theoretical investigation has been performed in non-cavitating and cavitating flow conditions, carried out in the centrifugal pump. The test used an open-loop drudge pump system to investigate the effects of Net positive suction head available (NPSHa) with a range (1 to 10 m), The centrifugal pump concert was coordinated by a flow rate with incremental values (80 to 450 m3/h), water temperature with values (12.5, 25.5, 35.5 and 45.5 )°C and pump speed with values (1000, 1200, 1400, 1600, 1800 and 2000 rpm). Thus, the theoretical study is included a two-phase flow 2-D simulation (ANSYS FLUENT software) within the centrifugal pump. It was noted that the percentage drop in the flow rate less than (2%) at a head drop of 3%, whereas the percentage drop in performance greater than (3%). This also showed that NPSHa decreases by increasing the flow rate and temperature and increases by reducing the velocity. This study showed that the noise level of the pump was increased with the decreasing NPSHa and the flow rate. Furthermore, the difference in the noise level between non-cavitating and cavitating flows was around (8 dB) (3 percent head fall). Thus, it was noted that Net positive suction head required (NPSHr) was increases by increasing the flow rate and decreases with higher temperature and lower velocity. The initiation of cavitation at NPSHa was approximately equal (4.3 m) to the flow rate (310 m3/h).