Combustion Gas Turbines - The Air Compressor PDF Print E-mail
Written by Norrie   
Wednesday, 13 January 2010 10:12
Article Index
Combustion Gas Turbines
Principles and Operation
The Air Compressor
The Combustion Chamber
The Compressor (HP) Turbine
The Variable-Angle Nozzles Load Turbine
Turbine/Compressor Lube Control Oil System
Turbine Hydraulic Oil Trip System
Turbine Overspeed Trip Mechanisms
Turbine System Details
All Pages

1. THE AIR COMPRESSOR (Figure. 17)

This is generally an ‘AXIAL FLOW COMPRESSOR’ and can be classed as the exact opposite of a turbine. (A turbine needs high energy fluid flow to cause rotation). An Axial Flow compressor needs a mechanical driver for its operation. The compressor itself consists of Rotors and Stators each having blades. The rotor blades are like those of the turbine and are similar to fan blades. As the wheels rotate, air is pushed forward with an increase in energy as velocity. The air then enters the stator blades where the velocity is decreased. This increases the pressure; (Bernoulli's Principle). As the air enters the stator blades, it is travelling in the wrong direction to be picked up by the next set of rotor blades. The stator blades, (like those of the steam turbine), also change the direction of the air flow into the next set of buckets. This process of compression, (conversion of Mechanical Energy), continues from stage to stage until the compressor discharges at its required pressure which, in the case of our turbine, has 14 stages and discharges at about 65 Psi. Because the compression of the air causes a decrease in volume, each succeeding stage is slightly smaller than the one before, (less blade surface area). The compression also causes an increase in temperature - up to 500 °F.

Figure. 16

Figure. 17 – Simplified diagram of an Axial-Flow Compressor

Last Updated on Wednesday, 24 February 2010 20:06