What is a typical consequence of running a centrifugal pump without water for an extended period?

Running a centrifugal pump without water for an extended period can lead to overheating of the impeller and may result in damage. When a pump operates dry, there is no water to absorb the heat generated by the mechanical energy produced by the impeller. This lack of cooling can cause the impeller materials, often made of plastic or metal, to reach high temperatures and potentially warp, melt, or fracture. Overheating can also harm the seals and bearings within the pump, leading to further mechanical failure.

The other options present situations that do not typically occur when a centrifugal pump runs dry. For instance, pump efficiency cannot improve without a fluid medium, as there is no work being done to move water. Similarly, discharge pressure is expected to either drop significantly or fluctuate when the pump operates without water, rather than increase. Lastly, without water, the flow rate would not increase; in fact, the absence of water means there would be little to no flow at all.