One person, one sentence of trivia
Thrust reverser is a deceleration device for aircraft landing, through which the airflow of the engine is reversed and slowed down. The thrust reverser device is not only easy to operate, but also has strong bearing capacity, low flow loss, and high stability and safety.
Some people say that thrust reverser is the reaction caused by the engine reversing, but it is not like that.
Thrust reverser refers to "the engine changes the direction of the air flow under normal thrust", that is, it generates thrust in the opposite direction of the aircraft's flight, thereby shortening the glide distance of the aircraft when landing. Generally, the high duct is thrust reverser by the method of reverse discharge of cold air flow than turbofan engine, and both military and civilian transport aircraft basically use thrust reversers.
Only the gas flow discharged from the incubation channel is basically not equipped with a thrust reverser. In addition, the thrust reverser principle of the turboprop engine is not forward jet, because the propeller blade of its propeller is an anti-propeller, that is, the blade angle of the propeller is designed to be greatly reversed, and the propeller blade is used to produce pneumatic braking backwards.
Thrust reversers are usually divided into several types:
One is the blade grid type thrust reverser device, it is composed of the reverse thrust deflector vane grid and the blade grid choke, when the engine anti-thrust device is opened, the fairing will move backwards and expose the blade grid, the air barrier will block the smooth air flow, and the air flow will be discharged along the direction of the blade grid diversion, so as to reduce the thrust reverser force to achieve deceleration, this reverse thrust is mainly used in the ducted airflow.
The other is the clam shell thrust reverser device, which is mainly used in large bypass ratio turbofan engines, such as the Boeing 747 series of large civil aircraft are basically using the clam shell thrust reverser device. Relatively speaking, its reverse thrust is relatively stable, but the structure is more complex.
The other is the target thrust reverser device, also known as the baffle type thrust reverser device. It is divided into fixed and sliding steerable types, and this thrust reverser device is usually used on small bypass ratio engines, and must also be installed at the rear end of the nacelle under the wing, so that the nacelle extends out of the wing, otherwise the air flow through the wing is likely to regenerate lift when the thrust is reversed.
There is also a baffle door thrust reverser device, also called "flap type rotating baffle door thrust reverser device", which is usually used in turbofan engines, rotated by the baffle door pivot, and the inner part of each group of air flow doors plays a role in blocking the smooth flow of airflow, while the outer part guides the air flow to discharge, reducing the interference of the reverse thrust mechanical manipulation on the internal flow, thereby producing a reverse thrust effect.
The thrust reverser device is related to the "nacelle design and engine bypass ratio", and the turbofan engine with a large bypass has a large duct air flow, and the ramjet resistance and thrust are naturally also large.
For example, the turbofan engine on civil aircraft usually has a thrust reverser, and its principle is to use a deflector to change the exhaust direction of the engine, so that the air flow is inclined forward and discharged to produce a backward pull force, so that the aircraft can slow down faster during the landing run.
Therefore, when the wheels of the aircraft are taxiing at high speed on the runway after landing, the vibration noise in the cabin is very loud, and even the roar of the engine can be heard, which is actually the noise generated by the engine opening the reverse deflector.