CENTRIFUGAL PUMPS Fluid Flow Summary The main points from this chapter are summarized below. Centrifugal Pumps Summary • Net positive suction head is the difference between the pump suction pressure and the saturation pressure for the fluid. • Cavitation is the formation and subsequent collapse of vapor bubbles on the impeller of a pump as the local pressure falls below and then rises above the saturation pressure of the fluid being pumped. • The pump laws can be used to determine the effect of varying the speed of a centrifugal pump on the flow, head, and power. V₁ n₂ n₁ V₂ H_p 1 n₂ n₁ 2 H_p 2 p₁ n₂ n₁ 3 p₂ • The combined pump curve for two centrifugal pumps in parallel can be determined by adding the individual flows for any given head. • The combined pump curve for two centrifugal pumps in series can be determined by adding the individual heads for any given flow. • The operating point (head and flow) of a system can be determined by plotting the pump curve and the system head loss curve on the same axes. The system will operate at the intersection of the two curves. HT-03 Page 56 Rev. 0