GAS TURBINE

TURBINE

A turbine is a rotary mechanical device that extracts energy from a fluid flow and converts it into useful work. Moving fluid acts on the blades so that they move and impart rotational energy to the rotor. Early turbine examples are windmills and waterwheels

HISTORY AND OPERATION THEORY

The word turbine was used by a french mining engineer claude burdin in 1822,which means vortex or turbo.A working fluid contains potential energy and kinetic energy. The fluid may be compressible or incompressible. Several physical principles are employed by turbines to collect this energy.

Design of turbine

Types of turbine

IMPULSIVE TURBINE

REACTION TURBINE

IMPULSIVE TURBINE

Implusive turbines change the direction of flow of a high velocity fluid or gas jet. The resulting impulse spins the turbine and leaves the fluid flow with diminished kinetic energy. There is no pressure change of the fluid or gas in the turbine blades.

Reaction turbineReaction turbines develop torque by reacting to the gas or fluid's pressure or mass. The pressure of the gas or fluid changes as it passes through the turbine rotor blades. A pressure casement is needed to contain the working fluid as it acts on the turbine stage(s) or the turbine must be fully immersed in the fluid flow (such as with wind turb

Gas Turbine

INTRODUCTION

A gas turbine, also called a combustion turbine, is a type of internal combustion engine. It has an upstream rotating compressor coupled to a downstream turbine, and a combustion chamber in between them.

Gas turbine converts natural gas or other fuels to generates energy.

Facts:-The GE 7F.05 gas turbine generates 225 MW, equivalent to 644,000 horsepower, or the power of 644 Formula One cars.

HOW IT WORKS

Gas turbine engine have 3 parts: A compressor to compress the

incoming air to high pressure. A combustion area to burn the

fuel and produce high pressure, high velocity gas.

A turbine to extract the energy from the high pressure, high velocity gas flowing from the combustion chamber

COMPRESSOR

In this engine air is sucked in from the right by the compressor. The compressor is basically a cone-shaped cylinder with small fan blades attached in rows).. In some engines the pressure of the air can rise by a factor of 30. The high-pressure air produced by the compressor is shown in dark blue.

COMBUSTION CHAMBER

high-pressure air then enters the combustion area, where a ring of fuel injectors injects a steady stream of fuel. The fuel is generally kerosene, jet fuel, propane, or natural gas.

The can is a hollow, perforated piece of heavy metal (shown here is half of the can in cross-section).

TYPES OF GAS TURBINE

OPEN CYCLE GAS TURBINE

CLOSE CYCLE GAS TURBINE

OPEN CYCLE GAS TURBINE

The Brayton cycle is a thermodynamic cycle that describes the workings of a constant pressure heat engine. The original Brayton engines used a piston compressor / expander gas turbine.

CLOSED CYCLE

In a closed system, no mass may be transferred in or out of the system boundaries. The system always contains the same amount of matter, but heat and work can be exchanged across the boundary of the system.

FUEL

One further advantage of gas turbines is their fuel flexibility. They can be adapted to use almost any flammable gas or light distillate petroleum products such as gasoline (petrol), diesel and kerosene (paraffin) which happen to be available locally, though natural gas is the most commonly used fuel. Crude and other heavy oils and can also be used to fuel gas turbines if they are first heated to reduce their viscosity to a level suitable for burning in the turbine combustion chambers

CREEP

 creep (sometimes called cold flow) is the tendency of a solid material to move slowly or deform permanently under the influence of mechanical stresses.. To limit creep, thermal coatings and super-alloys with solid-solution strengthening and grains boundary strengthening are used in blade designs. These coatings are often stabilized zirconium dioxide-based ceramics. Using a thermal protective coating limits the temperature exposure of the nickel super-alloy. This reduces the creep mechanisms experienced in the blade.

TYPES OF GAS TURBINE

TURBOJET

TURBOFAN

TURBOPROP

AFETRBURNIG TURBOJET

TURBOJET

A turbojet is the simplest of all aircraft turbine engines, consisting of four sections: compressor, combustion chamber, turbine section and exhaust. Turbojets were developed in Germany and England before World War II. In this type of engine, air is passed at a high rate of speed into the combustion chamber where the fuel inlet and igniter is located.  The turbine, driven by expanding air, causes thrust from accelerated exhaust gases.  Covington Aircraft has extensive experience in aircraft engine overhaul, as well as routine maintenance for these types of engine

TURBOPROP

Turboprop engines drive propellers through a reduction gear, which provides optimum propeller performance at slower rpm speeds. That translates to greater fuel efficiency and performance at slower airspeeds, which is why turboprops are popular aircraft turbine engines for small, commuter aircraft, cargo planes and agricultural use.  The propellers are less efficient as the aircraft speed increases, making them better for planes that do not have travel at higher speeds.  Because agricultural pilots rely on the consistency of their aircraft, Covington Aircraft has proudly worked on turboprop planes used in agriculture since 1972.

TURBOFAN

Merging the best features of the turbojet and turboprop, the turbofan is an aircraft turbine engine that diverts a secondary flow of air around the combustion chamber, which creates additional thrust.  This is the most modern version of an aircraft turbine engine and the one often found on high-speed transport and fighter planes.  Because many corporations choose turbofan engines, Covington Aircraft focuses on plane maintenance to keep corporate planes in the air, avoiding grounded aircraft due to maintenance issues.

AFTER-TURBOJET

Used predominately in fighter jets, afterburning turbojets include an afterburner in a core turbojet so that some of the energy from the exhaust helps to turn the turbine.  When the afterburner is on, additional fuel is injected into the exhaust stream, producing additional thrust.  Although this does provide additional speed for the aircraft, this type of aircraft turbine engine burns more fuel than traditional turbojet aircraft.