Turbines for Steam Power Plants P M V
Turbines for Steam Power Plants P M V Subbarao Professor Mechanical Engineering Department I I T Delhi Selection of Materials and Shape for Strong & Enduring Non. Biological Muscles ……
Development of A Sustainable Non. Biological Beast • The steam Power Plant is the largest non-biological beast. • Needs an elaborate anatomy for efficient conversion of chemical energy into Mechanical/Electrical energy. • The working fluid is the blood of this animal. • The pump is the heart of this beast & cyclically induces life into the working fluid. • The steam generator is the digestion system of this beast. • The steam turbine is the Muscle system of this beast. • The supercritical steam turbines are the strongest and most efficient non-biological muscles. • An essential requirement for human development.
KP is Like ATP
High Pressure High MKE Steam System Shaft power to generator Dead must be properly recycled Dead Steam
Power Plant Steam Turbines A Two Step Conversion of Microscopic Kinetic Power to Shaft Power…….
Thermodynamic Validation of Flowing Steam Work Vi High KP Negligible MLP Low KP Low MLP Low KP High MLP Ub Ve Work is said to be done by a system iff the sole effect external to the system can be reduced to raising of weight
The Steam Turbine • The more modern device to extract shaft power from Microscopic kinetic Power is the steam turbine. • Steam turbines have been the norm in various land based power plants for more than 100 years. • Turbine is a flow device develops a variable pressure form inlet to outlet. • A flowing steam performs work transfer, while moving from high inlet pressure (Live Steam) to low outlet pressure (Dead Steam). • The volume of steam continuously increases during this process. • The infinitesimal work done by a flowing fluid is defined as - Sign is important part of this definition. - Steam flowing in the direction of decreasing pressure performs +ve work.
Continuous Generation of Power • • How to introduce finite mass flow rate of steam? Area for Flow of Fluid. Proportional to the Length of the Blade. More Number of Blade Spacings.
Concept of Two Step Conversion : Kinetic Power to Shaft Ppwer • Steam turbine is a two part device: • Part 1: Energy Converter : Nozzles or Stationary Blades • Part 2: Energy Exchanger: Rotor or Moving Blades.
Classification of Rotors or Rotor Blades • Single Job Rotors: Only Exchange of Macro Kinetic Power from steam to Shaft Power via blades. • Also called as Impulse Blades/rotor. • Dual Job Rotors: Both energy conversion and Energy Exchange. • Known as Reaction Blades/rotor. • Best choice for Large Power Plant Turbines
Nozzle wheel and Blade Wheel
Top View of the Steam & Blade Interactions Va 1 U Vr 1 Va 1 Vr 1 Inlet Velocity Triangle U U Va 2 Vr 2 Exit Velocity Triangle
The Velocity Triangles a 2 Va 2 a 1 U Vr 2 b 1 b 2 Va 1: Inlet Absolute Velocity Vr 1: Inlet Relative Velocity Vr 2: Exit Relative Velocity Va 2: Exit Absolute Velocity Vr 1 a 1: Inlet flow Angle. b 1: Inlet Blade Angle. b 2: Exit Blade Angle. a 2: Exit flow Angle.
Selection of The Velocity Triangles a 2 Va 2 a 1 Ub Vr 2 b 2 Va 1 b 1 Va 1: Inlet Absolute Velocity Vr 1: Inlet Relative Velocity Vr 2: Exit Relative Velocity Va 2: Exit Absolute Velocity a 1: Inlet flow Angle. b 1: Inlet Blade Angle. b 2: Exit Blade Angle. a 2: Exit flow Angle. Vr 1
Blade Shape
Mechanical Arrangements of Steam Turbines • The blade velocity is defined at mean diameter of rotor wheel. • For same wheel speed, the blade velocity is directly proportional to blade height. • The height of the blade is proportional to specific volume of steam. • Solutions to Turbo-machinery Speed Issues (TSI). • Tandem Reheat Steam Turbine • Cross Compound Steam Turbine
Tandem Reheat Steam Turbine
Cross Compound Reheat Steam Turbine
Tandem-compound four-flow steam turbine
Large-Capacity Steam Turbines for Fossil Thermal Power Plant
Some Facts about Advanced Steam Turbines
Increased Magnitudes of Forces
Specific volume, m 3/kg Steam Volume Variation HP Range 0. 045 0. 04 0. 035 0. 03 0. 025 0. 02 0. 015 0. 01 0. 005 0 0 5 10 15 Steam Path, Mpa 20 25 30
Steam Volume Variation IP Range 0. 5 Specific volume, m 3/kg 0. 45 0. 4 0. 35 0. 3 0. 25 0. 2 0. 15 0. 1 0. 05 0 0 1 2 3 Steam Path, Mpa 4 5 6
Steam Volume Variation LP Range 35 Specific volume, m 3/kg 30 25 20 15 10 5 0 0 0. 1 0. 2 0. 3 Steam Path, Mpa 0. 4 0. 5 0. 6
Bleeding for FWHs : A win-win Idea
Efficiency of USC Turbine Modules: 800 MW
Typical ~ 500 MW Designs
Typical ~ 800 MW Designs
~ 1000 MW Designs
Reduction of Stage Losses
High-performance blading : Advanced Aero Design
Advanced Blades for ST
Modular Concept of Blade Construction
Major equipment in A Power Plant
Exhaust Diffuser For L P Turbine
Large Power Plant Condenser
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