What primarily determines the volumetric efficiency of a gear pump?

The volumetric efficiency of a gear pump is primarily determined by the close fit between the gears and the casing. This close fit minimizes the leakage between the gear teeth and the pump casing, ensuring that more of the displaced fluid actually moves through the system rather than recirculating back to the inlet.

When the gears are closely fitted, the volume of fluid that can be effectively moved with each rotation is maximized, which directly impacts the pump's ability to maintain a consistent flow rate and efficiency. If there is excessive clearance between the gears and the casing, fluid will escape from the discharge side back to the suction side, reducing the overall volumetric efficiency.

Factors such as fluid viscosity, pump speed, and design of inlet ports can influence performance but are secondary to the impact of the mechanical design characteristics that focus on minimizing internal leakage within the pump.