In terms of pump capacity, how does it vary with an increase in impeller diameter?

The capacity of a pump, specifically when considering centrifugal pumps, is directly influenced by the diameter of the impeller. As the impeller diameter increases, the pump is capable of moving a larger volume of fluid. This is because a larger impeller has more surface area to impart energy to the fluid, allowing it to be expelled from the pump with greater force and at a higher flow rate.

This relationship is governed by the principles of fluid dynamics and pump design, which indicate that larger impellers can produce greater flow rates due to their ability to accelerate the fluid more effectively. Additionally, an increase in impeller diameter typically results in increased head, which is the height that the pump can effectively move the fluid against gravitational forces. Therefore, the capacity of the pump increases as the impeller diameter grows, leading to enhanced performance in terms of fluid delivery.

In summary, an increase in the impeller diameter positively correlates with pump capacity, making the correct response to the question about pump capacity an increase.