Types of Jet engine (PART-1)

April 23, 2023

Types of Jet engine (PART-1)

JET ENGINE

Types of Jet engine

1)Turbojet

2)Turbofan (Fanjet)

3)Ramjet

4)Turboshaft

5)Scramjet

6)General Electric CF34

7)General Electric TF39

1)Turbojet

The turbojet is an airbreathing jet engine which is typically used in aircraft. It consists of a gas turbine with a propelling nozzle. The gas turbine has an air inlet which includes inlet guide vanes, a compressor, a combustion chamber, and a turbine (that drives the compressor). The compressed air from the compressor is heated by burning fuel in the combustion chamber and then allowed to expand through the turbine. The turbine exhaust is then expanded in the propelling nozzle where it is accelerated to high speed to provide thrust.

Frank Whittle from UK

Hans von Ohain from Germany,

developed the concept independently into practical engines during the late 1930s.

*Speed*

Turbojet aircraft work on the principle of accelerating a relatively small mass of air to a high speed. As optimum efficiency is achieved when the speed of the accelerated air approximates that of the aircraft,turbojet engines do not reach peak efficiency until speeds approaching mach 2.

*Use*

Turbojets engines are used to propel commercial airliners and military aircraft. The simplest version of aircraft jet engines is a turbojet. Turbojets were used on the first jet powered aircraft, the German Messerschmidt Me 262 used in World War II.

2)Turbofan (Fanjet)

The turbofan or fanjet is a type of airbreathing jet engine that is widely used in aircraft propulsion. The word "turbofan" is a portmanteau of "turbine" and "fan": the turbo portion refers to a gas turbine engine which achieves mechanical energy from combustion and the fan, a ducted fan that uses the mechanical energy from the gas turbine to force air rearwards. Thus, whereas all the air taken in by a turbojet passes through the combustion chamber and turbines, in a turbofan some of that air bypasses these components. A turbofan thus can be thought of as a turbojet being used to drive a ducted fan, with both of these contributing to the thrust.

Frank Whittle envisioned flight speeds of 500 mph in his March 1936 UK patent, "Improvements relating to the propulsion of aircraft", in which he describes the principles behind the turbofan, although not called as such at that time.

*Speed*

Turbofans are the most efficient engines in the range of speeds from about 500 to 1,000 km/h (270 to 540 kn; 310 to 620 mph), the speed at which most commercial aircraft operate.

*Use*

To move an airplane through the air, thrust is generated by some kind of propulsion system. Most modern airliners use turbofan engines because of their high thrust and good fuel efficiency.

3)Ramjet

A ramjet (aero thermodynamic duct), is a form of airbreathing jet engine that uses the forward motion of the engine to produce thrust. Since it produces no thrust when stationary (no ram air) ramjet-powered vehicles require an assisted take-off like a rocket assist to accelerate it to a speed where it begins to produce thrust. Ramjets work most efficiently at supersonic speeds.

René Lorin was a French aerospace engineer and inventor of ramjet

*Speed*

Mach 3 (2,300 mph; 3,700 km/h) and can operate up to speeds of Mach 6 (4,600 mph; 7,400 km/h).

*Use*

Ramjets can be particularly useful in applications requiring a small and simple mechanism for high-speed use, such as missiles.

4)Turboshaft

A turboshaft engine is a form of gas turbine that is optimized to produce shaftpower rather than jet thrust. In concept, turboshaft engines are very similar to turbojets, with additional turbine expansion to extract heat energy from the exhaust and convert it into output shaft power. They are even more similar to turboprops, with only minor differences, and a single engine is often sold in both forms.

The first turboshaft engine for rotorcraft was built by the French engine firm Turbomeca, led by its founder Joseph Szydlowski.

*Speed*

Propeller engines are most efficient for low speeds, turbojet engines for high speeds, and turbofan engines between the two. Turbofans are the most efficient engines in the range of speeds from about 500 to 1,000 km/h (270 to 540 kn; 310 to 620 mph), the speed at which most commercial aircraft operate.

*Use*

Turboshaft engines are commonly used in applications that require a sustained high power output, high reliability, small size, and light weight. These include helicopters, auxiliary power units, boats and ships, tanks, hovercraft, and stationary equipment.

*Important Images*