Siemens Gt Compressor & Turbine

SIEMENS GT COMPRESSOR & TURBINE

SIEMENS GAS TURBINE V94.2

ROTOR

Function of Rotor 

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To carries the compressor & turbine blades. Compressor convert the torque into kinetic energy Turbine convert the kinetic energy into torque.

Components of the Rotor 1. 2. 3. 4. 5. 6. 7.

8. 9.

Front hollow shaft Balance planes Compressor wheel Central hollow shaft Turbine wheel Rear hollow shaft Tie rod Damping ring O-ring seal

Function of Compressor Stator Blades To deflect the air stream passing through the blade passages in a direction of rotation of the rotor.  VIGV to vary the inlet air flow. This improve the efficiency of the unit under part load condition. 

Compressor Stator Blade

Stator Blade carrier

Dovetail root

Outer ring

Airfoil

Inner Double hook

ring

Variable Inlet Guide Vane

Outer ring

Pin Stator Blade carrier

Airfoil

Inner ring

Pin

Function of Compressor Stator 

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To secure the stator blades rings with the stator blades in position. To transmit the reaction forces due to flow & pressure to the outer casing The VIGV is to vary the sucked-in air mass flow & to improve the partial load efficiency.

SET RING

BEARING

VIGV  ADJUSTING SYSTEM

TRANSMISSION ROD

MOTOR

Function of Compressor Rotor Blades 

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To convert mechanical energy into kinetic & potential energy of the air. To pressurize the air. (16 stages) (compression ratio: 1 : 10)

 Airfoil

Blade root

Compressor Rotor Blade

Blow-off valves  

3 Blow-off valves. 2 blow-off valves at stage 5 Blow-off V1.1 & 1.2 close at 2900rpm

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1 blow-off valve at stage 10 Blow-off V2 close at 2300rpm

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To prevent compressor surge. Surge : Air flow unstable, hunting &  causes vibration.

Compressor surge protection GT will trip when  Speed more than 42 Hz (2520rpm) and  Differential pressure less than 30mbar

COMPRESSOR SURGE PROTECTION  Air from filter house

Compressor 2nd Stage

DP SW

Comp Surge Protection Speed > 2520rpm(42Hz) DP < 30 mbar GT trip Drain

Compressor Technical Data      

Compressor Compressor Compressor Compressor

flow rate : ratio : stages : outlet press :

468kg/s 1 : 10 16 10 bars

Compressor outlet temp : 330 deg C Blow-off valves : 3 Blow-off valve 1.1 & 1.2 at stage 5 close at speed : 2900rpm Blow-off valve 2 at stage 10 close at speed : 2300rpm

Function of Turbine Rotor Blades 

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To convert the thermal energy of the hot gas into mechanical energy. (4 stages) To drive the compressor & the generator.

Turbine rotor blades. 

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They are made from high temperature alloys to withstand the high mechanical &  thermal stress. The first stage rotor blades are cast hollow blades with ducts for guiding the cooling air. The 2nd stage rotor blades are provided with several ducts extending radial through the airfoil. The blades are coated to reduce high temperature corrosion.

Cooling air inlet

Cooling air outlet

Turbine rotor blade

Hottest at bigger end (4)

Function of Turbine Stator  

To secure the stator blades in position. To transmit the reaction forces due to flow & pressure to the outer casing.

Function of Turbine Stator Blades 

Together with the rotor blades, the turbine stator blades convert the energy of the working fluid into mechanical energy.

Function of Center Casing 

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To connect stator blade carrier to the exhaust casing. To contain the internal pressure. To accommodate the compressor &  turbine internals. To connect the combustion chambers.

Function of Exhaust Casing To support the bearing at the turbine end.  To provide flow paths for the gas.  Act as stationary diffuser to minimize the exhaust loss. 

Function of Exhaust Diffuser 

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To pass the exhaust gas into the stack  or HRSG To decrease the gas velocity &  resulting in a rise in static pressure.

Function of Inner Casing 

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To direct the flow of hot gas from the two combustion chambers to the turbine blades. To provide compressor air passing over its outer surface of all sides.

Function of Compressor Shaft Glands 

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To prevent the ingestion of air containing oil at the compressor intake. To reduce the internal leakage losses between the individual stages at the inner diameter of the stator blades. To adjust the flow of seal air to the turbine inlet at the compressor exit.

Stator blade row Compressor  bearing housing

Seal air duct

Shaft Gland Shim

Rotor disc Front hollow shaft

Labyrinth seal

9 Central hollow shaft 10 Ducts

11 Labyrinth seal 12 Compressor exhaust diffuser 13 Protective liner

Function of Turbine Shaft Glands  



To minimize the clearance losses. To prevent the hot gases from leaking through the spaces between the stator & rotor. The shaft gland at the turbine exit prevents the escape of the hot gas into the atmosphere & the ingress of  seal air into the bearing space.

1 Second-stage stator blade 2 Third-stage stator blade 3 Fourth-stage stator blade 4 X-ring 5 Seal ring 6 L-ring 7 Inner shroud 8 Hole 9 L-ring 10 Inner shroud 11 Hole

Function of Cooling &  Seal Air 

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To cool turbine rotor & stator metal temperature to below permissible operating temperature. To protect components not designed for high temperature application from direct contact with the combustion gas flow.

Function of Compressor Bearing Housing 

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To support the rotor & the turbine/ compressor unit. It forms part of the outer casing &  connect stator blade carrier to the compressor intake casing.

Function of Turbine Bearing Housing 

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To support the rotor in the exhaust casing. To house the turbine bearing

Function of Combine Journal & Thrust bearing 

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Support the rotor at the compressor end. To compensate the axial thrust &  To locate the rotor in axial position.

Function of Journal Bearing 

To support the rotor in the bearing housing at the turbine end.