TOPICS

Tuesday, March 8, 2011

Introduction to Jet Engines

Introduction to Jet Engines
An aircraft engine, or power plant, produces thrust to propel an aircraft. Reciprocating engines and turboprop engines work in combination with a propeller to produce thrust. Turbojet and turbofan engines produce thrust by increasing the velocity of air flowing through the engine. All of these power plants also drive the various systems that support the operation of an aircraft.

Turbine Engines
An aircraft turbine engine consists of an air inlet, compressor, combustion chambers, a turbine section, and exhaust. Thrust is produced by increasing the velocity of the air flowing through the engine. Turbine engines are highly desirable aircraft power plants. They are characterized by
  • Smooth operation
  • High power-to-weight ratio
  • Readily available jet fuel.
Types of Turbine Engines
Turbine engines are classified according to the type of compressors they use. There are three types of compressors—centrifugal flow, axial flow, and centrifugal-axial flow. Compression of inlet air is achieved in a centrifugal flow engine by accelerating air outward perpendicular to the longitudinal axis of the machine. The axial-flow engine compresses air by a series of rotating and stationary airfoils moving the air parallel to the longitudinal axis. The centrifugal-axial flow design uses both kinds of compressors to achieve the desired compression.

The path the air takes through the engine and how power is produced determines the type of engine. There are four types of aircraft turbine engines—turbojet, turboprop, turbofan, and turboshaft.

Turbojet
The turbojet engine consists of four sections: compressor, combustion chamber, turbine section, and exhaust. The compressor section passes inlet air at a high rate of speed to the combustion chamber. The combustion chamber contains the fuel inlet and igniter for combustion. The expanding air drives a turbine, which is connected by a shaft to the compressor, sustaining engine operation. The accelerated exhaust gases from the engine provide thrust. This is a basic application of compressing air, igniting the fuel-air mixture, producing power to self-sustain the engine operation, and exhaust for propulsion.





Turboprop
A turboprop engine is a turbine engine that drives a propeller through a reduction gear. The exhaust gases drive a power turbine connected by a shaft that drives the reduction gear assembly. Reduction gearing is necessary in turboprop engines because optimum propeller performance is achieved at much slower speeds than the engine’s operating rpm. Turboprop engines are a compromise between turbojet engines and reciprocating power plants. Turboprop engines are most efficient at speeds between 250 and 400 mph and altitudes between 18,000 and 30,000 feet. They also perform well at the slow airspeeds required for takeoff and landing, and are fuel efficient.



Turbofan
Turbofans were developed to combine some of the best features of the turbojet and the turboprop. Turbofan engines are designed to create additional thrust by diverting a secondary airflow around the combustion chamber. The turbofan bypass air generates increased thrust, cools the engine, and aids in exhaust noise suppression. This provides turbojet-type cruise speed and lower fuel consumption.


The inlet air that passes through a turbofan engine is usually divided into two separate streams of air. One stream passes through the engine core, while a second stream bypasses the engine core. It is this bypass stream of air that is responsible for the term “bypass engine.” A turbofan’s bypass ratio refers to the ratio of the mass airflow that passes through the fan divided by the mass airflow that passes through the engine core.





Turboshaft
The fourth common type of jet engine is the turboshaft. It delivers power to a shaft that drives something other than a propeller. The biggest difference between a turbojet and turboshaft engine is that on a turboshaft engine, most of the energy produced by the expanding gases is used to drive a turbine rather than produce thrust. Many helicopters use a turboshaft gas turbine engine. In addition, turboshaft engines are widely used as auxiliary power units on large aircraft.






11 comments:

  1. Thank you for the great help providing this information! Great blog indeed!

    ReplyDelete
  2. I have modifikation your system free combution system & fan compretion piston ,and system air intake, and exhause pipe type orivice ,and proses over laping fan,and type material fan compretion (hi temperatur )and power fuul .lub system,and maintence engin turboprp,
    do you know ENGINE MAGNET :) ???? I KNOW THAT

    ReplyDelete
  3. I like the valuable information you supply for your articles. I’ll bookmark your blog and take a look at again here regularly. I’m fairly sure I will learn a lot of new stuff right right here! Best of luck for the next!|
    jual thermal oil boiler
    Jual thermal oil Aspalt
    Jual Hot water boil
    Distributor Boiler steam
    Jual Boiler batu bara

    ReplyDelete
  4. The turbojet engine consists of four sections: compressor, combustion chamber, turbine section, and exhaust. The compressor section passes inlet air at a high rate of speed to the combustion chamber. The combustion chamber contains the fuel inlet and igniter for combustion. The expanding air drives a turbine, which is connected by a shaft to the compressor
    Thermal Oil pemanas CPO
    jual pipa boiler benteler
    Jual Hot Water Boiler

    ReplyDelete
  5. Very very nice information as I didn't familiar before. Thank a lot to Author

    ReplyDelete
  6. did anyone of you make out with a hot girl anytime if so send me her pictures

    ReplyDelete
    Replies
    1. ya i did with a really hot girl i dont have her pictures but i enjoyed so much she was so sexy

      Delete
  7. yes thank you for the information i was confused at this topic i was studying for ham radio

    ReplyDelete