1. Operation and Maintenance
Gas Turbine
Operation and Maintenance

2. OPERATION, PERFORMANCE AND MAINTENANCE
Gas Turbine
OPERATION, PERFORMANCE AND MAINTENANCE
CHAPTER 1
Introduction to the gas turbine engine
Gas Turbine Engine Classification
I- Industrial Gas Turbine
II- Air craft Gas Turbine
Major gas turbine implementation
Aircraft propulsion,
Oil and gas pipeline pumping
Offshore platforms
Utility power generation
Ship propulsion
Equipment Prime mover

3. CHAPTER 2
Energy transmission in gas turbine engines
CHAPTER 3
Fluid flow in gas turbines
Air in the compressor stages.
How pressure builds up through the compressor stages.
Flue gas in the turbine stages.
Air in the combustion chamber
CHAPTER 4
Gas turbine engine performance and specifications
1- Code and Standards
2- performance and
specifications

4. CHAPTER 5
Selected topics on gas turbine component design
CHAPTER 6
Maintenance of gas turbines
CHAPTER 7
Miscellaneous
Gas Turbine Thrust balance
Dry gas seal system
Bearings

5. CHAPTER 1
Introduction to the
gas turbine engine

6. Preface
The aircraft gas turbine engines test ran and produced thrust for the first time in 1937.
After 1945, aircraft gas turbine development efforts have been directed towards increasing pressure ratios, turbine inlet temperatures, component efficiencies, bypass ratios,
reliability and durability.
As a result, the specific fuel consumption of
the turbo-machine has been reduced and thrust to weight ratios have increased.

7. The turbo-machine is now one of the worlds most important prime movers.
The first jet engine developed only a few hundred pounds of thrust, while the latest generation of engines exceed 100,000 pounds thrust.
The engines for the land-based power plants exceed 250MW in power output.

8. Oil and gas pipeline pumping Offshore platforms
* Major gas turbine implementation
Aircraft propulsion,
Oil and gas pipeline pumping
Offshore platforms
Utility power generation
Ship propulsion
Equipment Prime mover

9. * Gas Turbine Engine Classification
I- Industrial Gas Turbine
The output is the all shaft power
The output can range from 100% thrust or essentially all shaft power
II- Air craft Gas Turbine
A- Turbo propeller
All of the power output is used to turn the propeller shaft.
a gear box is used between the engine and propeller
B- Turbofan
The power output is split between thrust and power to turn
the fan which comes after the compressor.
C- Turbo Jet
All of the power output is used in a form of thrust

10. I- Industrial Gas Turbine
GAS GENERATOR
TURBINES
COMBUSTOR
AIR COMPRESSOR
EXHAUST
DIFFUSER
AIR INLET

11. AIR
FUEL
EXHAUST

12. II- Air craft Gas Turbine
A- Turbo propeller
All of the power output is used to turn the propeller shaft.
Combustion
chamber
Propeller
Compressor
Turbine

13. The power output is split between
B- Turbofan
The power output is split between
1- power to turn the fan
2- Jet thrust
Exhaust
Fan
Compressor
Turbine

14. C- Turbo Jet All of the power output is used in a form of Jet thrust
Compressor
Exhaust
Turbine

15. Compact type GT. Combustion Chamber AIR IN EXHAUST AIR OUT FLUE GASES
Compressor Wheel
Turbine Wheel
AIR IN
EXHAUST
Rotating assembly cut-away
Note shaft laminations
Integral expander housing cover
Bearing housing made of stainless steel (non magnetic material is a must to avoid effects of the housing on the rotor).
AIR OUT
FLUE GASES
Combustion Chamber

16. Compact type GT. Compressor and Turbine Wheels
A range of expander wheels 3” (75mm) to 18” (450mm).
Note splitter vanes on larger wheel, these are used to optimize the gas flow through the wheel while balancing the increased frictional losses of more blades.
Compare performance of wheel with 2 blades and infinite blades. A 2 blade design provides minimal frictional losses but does not efficiently channel flow through the wheel. An infinite bladed wheel achieves optimum flow but frictional losses are too great.
MTC designs only 100% open wheels, NO brazing, welding, etc…
100% solid construction permits higher wheel stresses and faster tip speeds.

17. Shaft Attachment
Tapered attachment means wheels are removed easily, no scoring due to interference fit.
Note holes in expander wheel are pressure balance holes, to be addressed during ATE discussion.

18. CHAPTER 2
Energy transmission
in gas turbine engines

19. PCD = 8 to 12 bar Fuel Pressure is constant Atmospheric Air COMPRESSOR
TURBINE
Atmospheric Air
COMPRESSOR
PCD = 8 to 12 bar
Pressure is constant

20. Power distribution Assuming 100% Efficiency LOAD 35 MW 55 MW
COMBUSTION
CHAMBER
EXHAUST
25 MW
FUEL
35 MW
55 MW
20 MW
HOT AIR
COLD AIR
20 MW
35 MW
LOAD
10 MW
COMPRESSOR
TURBINE

21. Radiation& Mechanical losses
Sankey diagram
Exhaust
70%
Radiation& Mechanical losses 2%
Mechanical power
28%
Compressor Power
Fuel Input
100%
Turbine Power

23. Gas Turbine Combined Cycle
BOILER
COMPRESSOR
TURBINE
STEAM
Hot
Gas
Generator
STEAM TURBINE
Generator
Generator

24. CHAPTER 3
Fluid flow in
gas turbines

25. * Gas Turbine performance
Combustor
Turbine
Compressor
Exhaust
TEMRERATURE
PRESSURE

26. Thermal energy v2 < v1 P2 > P1 CONSTANT Plus FLUIDS FLOW
KINAMATIC ENERGY P2 P1
Thermal energy
Plus +
2 g V2 2 P2 +
2 g V1 2 P1
CONSTANT
v2 < v1
P2 > P1

27. = = = = V 2g P TOTAL ENERGY DIMENTIONS ( ft ) ( ft ) density 2 ft ft
sec = ft 2
sec =
( ft ) Lb 2 ft 3 = P ft 3 2 =
( ft )
density

30. FIXED FIXED AIR IN COMPRESSOR STAGES STATOR BLADES STATOR BLADES
MOVING
FIXED

31. Y2 Y1 STATOR BLADES COMP. BLADES STATOR BLADES FIXED FIXED MOVING
AIR IN COMPRESSOR STAGES
AIR PRESSURE THROUGH
COMPRESSOR BLADES
HAS NO CHANGE
AS X = X
STATOR BLADES
ACT AS DIFFUSER
AS Y2 > Y1 Y2 X X Y1
STATOR
BLADES
COMP.
BLADES
STATOR
BLADES
FIXED
FIXED
MOVING

32. V inlet = V outlet STATOR BLADES ACT AS DIFFUSER VOLUME INCREASED
HOW PRESSURE BUILDS UP
IN COMPRESSOR STAGES
STATOR BLADES ACT AS DIFFUSER
VOLUME INCREASED
PRESSURE INCREASED
VELOCITY (IN STATOR ) DECREASED
VELOCITY (IN MOVING ) INCREASED
VELOCITY IS CONSTANT
ALONG THE COMPRESSOR
V inlet = V outlet
STATOR
BLADES
COMP.
BLADES
STATOR
BLADES
MOVING
FIXED
FIXED

33. Axial Flow Compressor Pressure
Constant Velocity
Velocity
Pressure increased
Pressure
Stator
Rotor
Stator
Rotor
Stator

34. FIXED FIXED FLUE GASES IN GAS TURBINE. STATOR STATOR BLADES BLADES
MOVING

35. FIXED FIXED FLUE GASES IN GAS TURBINE. STATOR STATOR STATOR BLADES
ACT AS NOZZELS
STATOR
BLADES
STATOR
BLADES
TURBINE
BLADES
FIXED
MOVING
FIXED

36. TEMPERATURE DECREASED
HOW POWER GENERATES IN GT. STAGES
STATOR BLADES ACT AS NOZZELS
THE FLUE GASES VELOCITY ENERGY WILL BE TRANSFERED TO TURBINE BLADES
ENERGY PARAMETERS THROUGH THE TURBINE INLET AND OUTLET WILL BE :
PRESSURE DECREASED
VELOCITY DECREASED
TEMPERATURE DECREASED
VOLUME INCREASED

37. A AIR THROUGH COMPRESSOR STAGES 1- PRESSURE INCREASED
2- VELOCITY CONSTANT
3- TEMPERATURE INCREASED
4- VOLUME DECREASED

38. B AIR THROUGH COMBUSTION CHAMBERS 1- PRESSURE CONSTANT
2- TEMPERATURE INCREASED
3- VOLUME INCREASED

39. C FLUE GASES THROUGH TURBINE STAGES 1- PRESSURE DECREASED
2- VELOCITY DECREASED
3- TEMPERATURE DECREASED
4- VOLUME INCREASED

40. performance and specifications
CHAPTER 4
Gas turbine engine
performance and specifications

41. * Code and Standards API STD 616 Gas Turbines for Petroleum,
Chemical, and Gas Industry Services
API RP 11PGT Recommended Practice for
Packaged Combustion Gas Turbines

42. General System Operational Sequence Single shaft Generator Set
100% Ngp
Supply Lube Oil to :
Turbine
Gear box
Generator bearings
Accessory driver
75% Ngp
Variable Guide
vanes start to open
Bleed Valve
start to close
65% Ngp
Starter Drop out
Main L/O Pump
supply all pressure
Back-up Lube Oil
Pump stopped
83 % Ngp
Bleed Valve
Fully closed
Turbine driven
L/O Pump starts as Engine rotates
Ngp Percent
15% to 20% Ngp
Purge
Ignition Command
Fuel valve opened
General System
Operational
Sequence
Single shaft
Generator Set
START
COMMAND
Back-up Lube Oil
Pump started
Commence
Rotation
Elapsed time

43. IN CASE OF GAS TURBINE AIR COMPRESSOR SURGE BLEED VALVE WILL OPEN43 43

44. P V SIMPLE CYCLE P-V DIAGRAM OF G.T. ATMS 3 2 4 1 COMBUSTION
COMPRESSION 4
TURBINE (EXPANSION)
ATMS V

45. A THERMAL POWER ENERGY MACHINE
WHY GAS TURBINE
CONSIDERED AS
A THERMAL POWER ENERGY MACHINE

46. P Wc = m * Cp ( T2 – T1 ) KW V Q f = m * Cp ( T3 – T2 ) KW
GAS TURBINE
POWER
COMBUSTION 2 3 P
TURBINE (EXPANSION)
1- COMPRESSION STAGE
Wc = m * Cp ( T2 – T1 ) KW
COMPRESSION
ATMS 4 1 V
2- COMBUSTION STAGE
Q f = m * Cp ( T3 – T2 ) KW
W c = Compressor power kw
W t = Turbine power kw
Q f = Fuel produced power kw
m = Air mass flow kg/sec.
Cp = Specific heat kj/kg.
T = Absolute Temperature k
3- TURBINE POWER STAGE
Wt = m * Cp ( T3 – T4 ) KW k

47. ξ ξ = = = OVERALL EFFICIENCY Wt - Wc Q f ( T3 – T4 ) – ( T2 – T1 )
OUTPUT
INPUT
* 100
( T3 – T4 )
– ( T2 – T1 )
T3 – T2 =
* 100
( T3 –T2)
– (T4 – T1 )
T3 – T2 =
* 100

48. OVERALL EFFICIENCY ξ T
1 –
( T4 – T1 )
( T3 – T2 ) =
* 100

49. ξ ξ To improve * EXHAUST TEMP. T4 TO BE AS LOW AS POSSIBLE = 1 –
To improve ξ T =
1 –
( T4 – T1 )
( T3 – T2 )
* EXHAUST TEMP. T4 TO BE AS LOW AS POSSIBLE
* FIRING TEMP T3 TO BE AS HIGH AS POSSIBLE
* COMP.OUT.TEMP.T2 TO BE AS LOW AS POSSIBLE
* T2 - T to be considered

50. ξ ξ ξ ξ ξ 1 – AMBIENT TEMPERATURE = 20 C
EXAMPLE
FIND THE Turbine EFFICIENCY OF
G.T HAS THE FOLLOWING DATA: -
1 – AMBIENT TEMPERATURE = 20 C
2 – FIRING TEMPERATURE = 950 C
3 – EXHAUST TEMPERATURE = 490 C
4 – COMP. OUT TEMPERATURE = 300 C O
T1 = = K
T3 = = K
T4 = = K
T2 = = K O ξ =
1 –
( T4 – T1 )
( T3 – T2 ) ξ =
1 –
( 763 – 293 )
( 1223 – 573 ) ξ =
1 –
( 470 )
( 650 ) ξ =
1 –
( 0.72 ) ξ =
0. 28
= 28%

51. ENTHALPY AND KINETIC ENERGY
h = Cp T
Cp = Btu / Ib F
Cp = KJ / kg C

53. Two shaft Gas Turbine AIR Gas Compressor Combustion Chamber POWER
LOW
PRESSURE
6000 RPM
COMP
HIGH
PRESS
9000
RPM
COMPRESSOR
LOW PRESSURE
6000 RPM
TURBINE
HIGH
PRESS
9000
RPM
AIR
Combustion Chamber
POWER
TURBINE
5000 RPM
Gas Compressor