What is the primary outcome of connecting two similar centrifugal pumps in series?

Connecting two similar centrifugal pumps in series is a method used to increase the pressure output of the pumping system. When pumps are arranged in series, the hydraulic energy created by the first pump is transmitted to the second pump, allowing the second pump to work on the fluid that has already been pressurized. This connection effectively allows the second pump to add its pressure rise to the pressure rise provided by the first pump.

The primary outcome of this configuration is the doubling of pressure while maintaining a constant volume flow rate. Each pump will contribute to the total pressure, and since the flow through the pumps is the same, the volume does not change.

This setup is particularly beneficial in applications where higher discharge pressures are needed, such as in systems that require overcoming significant head losses or when conveying fluids to elevated locations.

Thus, the connection of the two centrifugal pumps in series results in increased pressure output while keeping the flow rate consistent, which is why the identified choice is correct.