page 2 Flashcards
What does the exhaust cone prevent?
The exhaust cone prevents the hot gases flowing across the disc face, further reducing disturbance, and preventing overheating of the disc.
Example sentence: The exhaust cone plays a crucial role in maintaining the proper airflow in the gas turbine engine.
What supports the rear turbine bearing inside the exhaust cone?
The rear turbine bearing is supported inside the exhaust cone via turbine rear support struts.
Additional information: The turbine rear support struts are streamlined by fairings to straighten out any residual whirl in the gas stream.
What increases the gas velocity to speeds of Mach 1 in a turbojet engine?
The convergent propelling nozzle increases the gas velocity to speeds of Mach 1 in a turbojet engine at virtually all throttle openings above idle.
Example sentence: Achieving Mach 1 velocity in the propelling nozzle is essential for optimal engine performance.
What does it mean when the nozzle is said to be choked?
When the nozzle is said to be choked, it implies that no further increase in velocity can be obtained unless the gas stream temperature is increased, for instance with the assistance of ‘reheat’.
Additional information: The term ‘choked’ is used to describe the maximum achievable gas velocity at sonic speed.
What are the conditions at full power in the context of the danger areas?
At full power, the conditions include a temperature of °C, a velocity of knots, and a distance in feet.
Figure 18.2 illustrates the inlet and exhaust danger areas at different distances.
