Which type of pumps are classified as low pressure pumps in the fuel system of most transport aircraft?

Centrifugal pumps are classified as low pressure pumps in the fuel system of most transport aircraft primarily due to their operating mechanism and design. These pumps utilize a rotating impeller to increase the velocity of the fuel, converting that velocity into pressure as the fuel exits the pump. This design is well-suited for applications where a steady flow of fuel is required at relatively low pressures, which is common in transport aircraft fuel systems for tasks such as fueling the engines, transferring fuel between tanks, or supplying auxiliary systems.

Centrifugal pumps typically excel in handling large volumes of fluid and can operate smoothly without creating excessive pressure, making them ideal for low-pressure applications. Their ability to maintain a consistent flow rate with minimal pulsation is advantageous for aircraft systems that demand reliability and stability.

In contrast, other types of pumps, like piston and diaphragm pumps, generally operate at higher pressures and are intended for applications requiring positive displacement. Gear type pumps, while capable of generating some pressure, are more commonly associated with transferring fluids in industrial applications rather than in aviation fuel systems.

Therefore, centrifugal pumps are recognized for their efficient design in providing low-pressure fuel flow, which is crucial for the aircraft's operational requirements.