Final answer:
A gas turbine APU operates at variable speeds, depending on its design, typically ranging from 30,000 to 40,000 RPM. It maintains this speed using a control system that manages fuel supply and air intake, ensuring consistent power output and efficient operation.
Step-by-step explanation:
The speed at which a gas turbine APU (Auxiliary Power Unit) operates varies depending on the specific design and purpose of the unit. Generally, these turbines must maintain a stable speed to ensure consistent power output and operation. The speed is maintained using a control system that regulates the fuel supply and air intake, ensuring that the turbine operates within its design limits for power generation or providing pneumatic pressure for various aircraft systems. For instance, some APUs may operate at speeds ranging from 30,000 to 40,000 RPM (Revolutions Per Minute).
To maintain this speed, the control system continuously monitors the APU's operation, making adjustments as needed to account for changes in load, temperature, and other environmental factors. These adjustments ensure that the APU consistently delivers the required power while operating safely and efficiently.
While the turbofan engine described here, accelerates at a constant rate to reach an angular velocity, the gas turbine APU has control mechanisms in place to maintain its operational speed. The same principles of mechanics are applied, but with the added complexity of maintaining the rotational speed under varying conditions.