What is a primary characteristic of a positive displacement pump?

A primary characteristic of a positive displacement pump is its ability to trap a fixed volume of liquid and then discharge that volume through the discharge port. This mechanism is fundamental to how positive displacement pumps operate. Instead of relying on kinetic energy to move fluid, as seen in centrifugal pumps, positive displacement pumps physically displace a specific amount of fluid with each pump cycle. This ensures a consistent flow rate regardless of changes in pressure within the system, making them particularly effective for applications requiring precise fluid transfer.

In contrast, the other options refer to different mechanisms of fluid movement. The first option discusses centrifugal force, which is associated with centrifugal pumps that rely on rotational energy to move fluid. The second option mentions creating a vacuum, which is more related to suction pumps or certain types of filtration systems. The last option focuses on fluid dynamics, which are not the central operating principle for positive displacement pumps, as their operation is based on mechanical action rather than dynamic flow principles.