The axial compressor is used in most modern gas turbines. It has a cylindrical hub with “rings” or stages of rotor blades. In between each set of rotor blades are the stator blades. The stator blades do not rotate and they are a part of the case that surrounds the compressor rotor. The case is often in two halves, so that the compressor can be opened and inspected or repaired. The number of stages is usually determined by the number of rows of blades on the rotating rotor. There is usually one more set of stator vanes than rotor blades since the stators are at the front and rear end of the compressor. At the ends of the larger sized stator blades toward the center of the rotor are shrouds that connect the ends of the stator blades together. The shrouds help prevent air from being lost in the inner part of the compressor or being lost between stages and it helps reduce vibrations. Small stators toward the rear of the compressor often do not have shrouds. Each stage of stator blades changes the direction of the air flow (angle of attack) as it leaves the rotor, so it will enter the next rotor stage at the correct angle.

     Figure - Edge View of Axial Compressor