Gas Turbine engines

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Gas Turbine engines
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Compressors
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Types of Compressors

• Reciprocating air compressors are the type of
  compressor found in most small shops, they are
  positive displacement machines.
• This means that they increase the pressure of the
  air by reducing its volume, this is accomplished
  by a piston moving up a cylinder compressing the
  air above it.
• Single-stage and two-stage reciprocating
  compressors are commercially available.
  Single-stage compressors are generally used for
  pressures in the range of 70 psi to 150 psi.
  Two-stage compressors are generally used for
  higher pressures.

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Rotary Screw Compressors

• Rotary air compressors are also positive
  displacement compressors. The most common rotary
  air compressor is the single stage helical or
  spiral lobe oil flooded screw air compressor,
  consisting of two rotors within a casing where
  the rotors compress the air internally. There are
  no valves. These units are basically oil cooled
  with the oil sealing the internal clearances.
  Since the cooling takes place right inside the
  compressor, the working parts never experience
  extreme operating temperatures making them
  continious duty compressors.

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Centrifugal Compressors

• The centrifugal air compressor is a dynamic
  compressor which depends on a rotating impeller
  to compress the air.
• In order to do this efficiently, centrifugal
  compressors must rotate at higher speeds than the
  other types of compressors.
• These types of compressors are designed for
  higher capacity because flow through the
  compressor is continuous and oil free by design.

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• Centrifugal compressors consist of three main
  parts, as shown in Figure 1.
• The first is a rotating impeller, which imparts
  work to the gas by increasing its angular
  momentum. The fluid static pressure and absolute
  velocity (stationary frame of reference) increase
  through the impeller passage.
• The second component is the diffuser section,
  often with vanes to increase the effectiveness.
  The diffuser converts the kinetic energy into the
  static pressure by decelerating the fluid.

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• The third and final component is a volute or
  collector, used for collecting the gas from
  diffuser and delivering to the outlet pipe. A
  volute has two functions collection and
  diffusion.
• The volute must collect and transport the fluid
  to the downstream system. It also raises the
  static pressure by converting kinetic energy
  (?u2) to potential energy (static pressure).
• The latter function has performance benefits, as
  the discharge pressure is increased.

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Figure 1 Centrifugal compressor layout. (a) A
cross-sectional view, showing the impeller
followed by a vaned diffuser, and a volute. (b)
An isometric view of the package.
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Examples of Application

• Impeller of a compressor

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Examples of Application

• Vaned diffuser for centrifugal compressor

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Examples of Application

• Turbo charger

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Axial Compressor