🔍 Key Concepts

• Gas turbine lube oil systems normally require a positive displacement pump to maintain flow at all shaft speeds and pressures. • Compare how rotary pumps (like vane or centrifugal) move fluid versus reciprocating or diaphragm types. • Think about which pump type is commonly used for continuous high‑flow lubrication and scavenging on main propulsion machinery.

💭 Think About

• Ask yourself which of the four options can provide a steady, non‑pulsating flow suitable for cooling and lubricating high‑speed bearings. • Which pump type would be impractical or overly complex to use as a combined main lube and scavenging pump on a large marine gas turbine? • Of the listed pumps, which one is most often associated with engine lube oil systems rather than with fuel metering or small transfer duties?

✅ Before You Answer

• Eliminate any pump type that is not positive displacement or that loses capacity badly as system pressure changes. • Eliminate options that typically produce strong pulsations in flow, which are undesirable for bearing lubrication. • Consider which option is most mechanically suited to direct drive from the engine or accessory gearbox for continuous operation.