can we increase the efficiency of a centrifugal pump by using it with a jet pump?if yes how?if no why?

Answer 1

Remember your question is about the efficiency of the centrifugal pump and not the system (the two pumps in series).

The system efficiency is likely go down depending of the relative efficiency of the two pumps.

The efficiency of the centrifugal pump depends on where on the head capacity curve you are operating. Only with this information can you determine in which direction the efficiency of the centrifugal pump will go.

You really need to know the performance of both pumps and define the envelope for your efficiency calculations.

Answer 2

If a jet pump were used at the suction of the centrifugal pump, the greater net positive suction head would be provided to the centrifugal pump, therefore less cavitation and better pumping. On the outlet, the jet pump would raise the discharge pressure. As far as efficiency though, the systems efficiency would go down due to more work and head-loss.

Answer 3

Maybe, but I doubt it if you calculate overall efficiency. Of course you don't give any specific information upon which to base our opinions. The potential problems I see is the best bet for efficiency gain would be to use the jet pump on the suction of the centrifugal pump, raising the incoming suction head and therefore the discharge head. But I doubt the jet pump would have the flow capacity to keep up with the cenrifugal pump, so the gain would not last.