15.7 Exhaust - 3q Flashcards
Exhaust main purpose?
Accelerate airflow from the turbine to make thrust. Also that the gasses leave the turbine at the correct direction and optimum velocity
Exhaust pipe is? Purpose?
exhaust pipe is parallel and has no significant effect on airflow but clears it from aircraft structure
What type of duct is on a subsonic exhaust?
Convergent
High bypass exhaust systems use?
- Internally mixed
- Externally mixed
Lobe Mixer also called?
Corrugated exhaust
Lobe mixer does what?
has a scalloped design so hot primary gas and cold fan exhaust air can mix better
Lobe mixer advantages and disadvantages
Advantages
* Thrust augmentation
* Jet noise reduction
* Exhaust cooling
* Infrared suppression
* HIgh propulsion efficiency
Disadvantages
* Higher fuel consumption
CNA stands for?
Common Nozzle Assembly
In a turboprop, how much gas energy is used for propeller and accessories, and how much for thrust?
90% for driving the propeller and accessories
10% for thrust
Does a turboshaft produce thrust?
No. The maximum amount of energy is absorbed by the turbine so no jet thrust is obtained
The exhaust pipe on a turboshaft is surrounded by what?
An exhaust muffler and Heat shield
Exhaust nozzle task on a Turbojet?
converting gas potential energy to kinetic energy
Each particular engine has?
each particular engine has an exhaust nozzle unique to it
Choked nozzles CAN?
provide extra thrust
Why do turbofans have a higher propulsive efficiency?
Because velocity and temperature of the exhaust gasses are lower
