
Electric pump power requirement
I am designing an electric methane pump, using CF turbo, an automated pump design software. I set up two configurations, one with a single centrifugal impeller, and one with a centrifugal impeller+inducer. The setpoint of both is the same, but somehow the single stage version has 42 kw required driving power, with 52% efficiency, while the dual stage version has 40 kw power requirement with 19.7% efficiency. How is this possible? Shouldn’t the more efficient pump have a lower shaft power requirement?