OBJECTIVES 1. DESCRIBE the process for converting heat energy to rotational energy in turbines. 2. DESCRIBE the components that comprise a turbine. 3. DESCRIBE reaction and impulse turbine blading. 4. DESCRIBE the function of a nozzle in turbine blading. 5. EXPLAIN the concept of turbine staging. 6. DEFINE turbine efficiency. 7. DESCRIBE the steam flow path through a turbine. 8. DESCRIBE accessories and support systems associated with turbines. 9. DESCRIBE failure mechanisms and symptoms associated with turbines. ABC / Mechanical Science / Chapter 10 / TP 10 - 1 / Rev 02

WORK IN A TURBINE VISUALIZED Fig 10-1 ABC / Mechanical Science / Chapter 10 / TP 10 - 2 / Rev 02

IMPULSE TURBINE PRINCIPLE NOZZLE STEAM CHEST ROTOR Fig 10-3 ABC / Mechanical Science / Chapter 10 / TP 10 - 3 / Rev 02

PRESSURE-VELOCITY DIAGRAM FOR A TURBINE NOZZLE ENTRANCE HIGH THERMAL ENERGY HIGH PRESSURE LOW VELOCITY STEAM INLET EXIT LOW THERMAL ENERGY LOW PRESSURE HIGH VELOCITY STEAM EXHAUST PRESSURE VELOCITY Fig 10-4 ABC / Mechanical Science / Chapter 10 / TP 10 - 4 / Rev 02

IMPULSE TURBINE NOZZLE-BLADE ARRANGEMENT Fig 10-5 ABC / Mechanical Science / Chapter 10 / TP 10 - 5 / Rev 02

PRESSURE-VELOCITY DIAGRAM FOR A MOVING IMPULSE BLADE TURBINE SHAFT DIRECTION OF SPIN ENTRANCE HIGH VELOCITY STEAM INLET REPRESENTS MOVING IMPULSE BLADES EXIT LOW VELOCITY STEAM EXHAUST VELOCITY PRESSURE Fig 10-6 ABC / Mechanical Science / Chapter 10 / TP 10 - 6 / Rev 02

PRESSURE-VELOCITY DIAGRAM FOR A FIXED IMPULSE BLADE FIXED BLADES NO MOVEMENT ENTRANCE STEAM INLET REPRESENTS NON-MOVING IMPULSE BLADES EXIT STEAM EXHAUST PRESSURE VELOCITY NOTE: PRESSURE AND VELOCITY OF STEAM DO NOT CHANGE ACROSS FIXED IMPULSE BLADE. IT IS USED ONLY FOR DIRECTIONAL FLOW CONTROL. Fig 10-7 ABC / Mechanical Science / Chapter 10 / TP 10 - 7 / Rev 02

REACTION TURBINE PRINCIPLE STEAM CHEST ROTOR Fig 10-8 ABC / Mechanical Science / Chapter 10 / TP 10 - 8 / Rev 02

PRESSURE-VELOCITY DIAGRAM FOR A MOVING REACTION BLADE TURBINE SHAFT DIRECTION OF SPIN ENTRANCE HIGH PRESSURE HIGH VELOCITY STEAM INLET REPRESENTS MOVING REACTION BLADES EXIT LOW PRESSURE LOW VELOCITY STEAM EXHAUST PRESSURE VELOCITY Fig 10-9 ABC / Mechanical Science / Chapter 10 / TP 10 - 9 / Rev 02

PRESSURE-VELOCITY DIAGRAM FOR A FIXED REACTION BLADE FIXED BLADES NO MOTION ENTRANCE HIGH PRESSURE LOW VELOCITY STEAM INLET REPRESENTS NON-MOVING REACTION BLADES EXIT LOW PRESSURE HIGH VELOCITY STEAM EXHAUST NOTE: A FIXED REACTION BLADE IS ESSENTIALLY A NOZZLE PRESSURE VELOCITY Fig 10-10 ABC / Mechanical Science / Chapter 10 / TP 10 - 10 / Rev 02

IMPULSE TURBINE STAGING MOVING BLADE PRESSURE VELOCITY NOZZLE 1ST STAGE – NOZZLE & MOVING FIXED BLADE MOVING 2ND STAGE – FIXED & MOVING Fig 10-11 ABC / Mechanical Science / Chapter 10 / TP 10 - 11 / Rev 02

REACTION TURBINE STAGING NOZZLE MOVING BLADE FIXED BLADE MOVING BLADE PRESSURE 1ST STAGE – NOZZLE & MOVING BLADE 2ND STAGE – FIXED & MOVING BLADE VELOCITY Fig 10-12 ABC / Mechanical Science / Chapter 10 / TP 10 - 12 / Rev 02

PRESSURE COMPOUNDED TURBINE Fig 10-13 ABC / Mechanical Science / Chapter 10 / TP 10 - 13 / Rev 02

VELOCITY COMPOUNDED TURBINE Fig 10-14 ABC / Mechanical Science / Chapter 10 / TP 10 - 14 / Rev 02

VELOCITY COMPOUNDED IMPULSE TURBINE Fig 10-15 ABC / Mechanical Science / Chapter 10 / TP 10 - 15 / Rev 02

PRESSURE COMPOUNDED IMPULSE TURBINE Fig 10-16 ABC / Mechanical Science / Chapter 10 / TP 10 - 16 / Rev 02

PRESSURE-VELOCITY COMPOUNDED IMPULSE TURBINE Fig 10-17 ABC / Mechanical Science / Chapter 10 / TP 10 - 17 / Rev 02

PRESSURE – VELOCITY – COMPOUNDED IMPULSE TURBINE (CURTIS AND RATEAU STAGING TURBINE) Fig 10-18 ABC / Mechanical Science / Chapter 10 / TP 10 - 18 / Rev 02

PRESSURE COMPOUNDED REACTION TURBINE Fig 10-19 ABC / Mechanical Science / Chapter 10 / TP 10 - 19 / Rev 02

PRESSURE-VELOCITY COMPOUNDED REACTION TURBINE Fig 10-20 ABC / Mechanical Science / Chapter 10 / TP 10 - 20 / Rev 02

Difference between impulse and reaction turbine It consists of nozzles and moving blades Moving blades (nozzles) and fixed blades (nozzles) Steam stikes the blade with kinetic energy Steam passes over the moving blades with pressure and kinetic energy Pressure drops in nozzles and not in moving blades Pressure drops in fixed blade as well as moving blade Blade speed and steam speed are high Blade speed and steam speed are less (small pressure drop) Profile type blade shape Aerofoil type blade shape Low efficiency high efficiency Suitable for small power requirements Suitable for high and medium power requirements Occupies less space Occupies more space ABC / Mechanical Science / Chapter 10 / TP 10 - 21 / Rev 02

GENERAL ENERGY EQUATION FOR A TURBINE ABC / Mechanical Science / Chapter 10 / TP 10 - 22 / Rev 02

IDEAL VS. REAL LOW PRESSURE TURBINE PROCESS (b) T-s DIAGRAM P1 P2 2 2 T1 T2 & T2 WET STEAM CRITICAL POINT SATURATION VAPOR LINE 1 s SPECIFIC ENTROPY (Btu/lbm R) TEMPERATURE ( F) (a) h-s DIAGRAM 2' h1 h2 SPECIFIC ENTHALPY (Btu/lbm) h2 WET STREAM Fig 10-21 ABC / Mechanical Science / Chapter 10 / TP 10 - 23 / Rev 02

TURBINE EFFICIENCY TURBINE WORK Equation 10-3 Equation 10-4 Eq 10-3, 10-4 ABC / Mechanical Science / Chapter 10 / TP 10 - 24 / Rev 02

EXAMPLE The enthalpy of the steam entering a turbine is 1,200 Btu/lbm and the ideal exit enthalpy of the exhaust steam is 780 Btu/lbm. The steam flow rate is 1  106 lbm/hr. The turbine efficiency is 90%. 1 HP = 2.54  103 Btu/hr. 1. Calculate the ideal work and shaft horsepower, produced by the turbine. Ex 10-1 ABC / Mechanical Science / Chapter 10 / TP 10 - 25 / Rev 02

EXAMPLE Using the conversion factor: 2. Calculate the real work if  = 90%. Ex 10-1 ABC / Mechanical Science / Chapter 10 / TP 10 - 26 / Rev 02

AXIAL FLOW TURBINE Fig 10-22 ABC / Mechanical Science / Chapter 10 / TP 10 - 27 / Rev 02

DOUBLE AXIAL FLOW TURBINE Fig 10-23 ABC / Mechanical Science / Chapter 10 / TP 10 - 28 / Rev 02

JOURNAL BEARING LUBRICATION Shaft at Rest Thin Pad of Oil Formed Oil Wedge Supports the Shaft Rotation Starts Fig 10-24 ABC / Mechanical Science / Chapter 10 / TP 10 - 29 / Rev 02

THRUST BEARING BABBIT Fig 10-25 ABC / Mechanical Science / Chapter 10 / TP 10 - 30 / Rev 02

TAPERED-LAND THRUST BEARING COLLAR ROTATION OIL BEARING SEGMENTS WEDGE THRUST COLLAR SHAFT Fig 10-26 ABC / Mechanical Science / Chapter 10 / TP 10 - 31 / Rev 02

TYPICAL LUBE OIL SYSTEM Fig 10-27 ABC / Mechanical Science / Chapter 10 / TP 10 - 32 / Rev 02

LABYRINTH PACKING GLANDS Fig 10-28 ABC / Mechanical Science / Chapter 10 / TP 10 - 33 / Rev 02

CARBON PACKING GLANDS Fig 10-29 BLOCK OR STRIP BORMETRIC CONDENSER (VACUUM) PACKING SPRING KEY TURBINE SHELL ATMOSPHERE SHAFT Fig 10-29 ABC / Mechanical Science / Chapter 10 / TP 10 - 34 / Rev 02

TYPICAL TURBINE EXHAUST HOOD COOLING SYSTEM SCHEMATIC Fig 10-30 ABC / Mechanical Science / Chapter 10 / TP 10 - 35 / Rev 02