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 Steam Dead must be properly recycled

Power Plant Steam Turbines A Two Step Conversion of Microscopic Kinetic Power to Shaft Power…….

Work is said to be done by a system iff Thermodynamic Validation of Flowing Steam Work Low KP High MLP Vi High KP Negligible MLP Ub Ve Low KP Low MLP Work is said to be done by a system iff the sole effect external to the system can be reduced to raising of weight

Sign is important part of this definition. 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 Va1 U Vr1 Va1 Inlet Velocity Triangle Vr1 U U Vr2 Va2 Exit Velocity Triangle Vr2

The Velocity Triangles U a2 a1 b2 b1 Va1 Va2 Vr1 Vr2 Va1: Inlet Absolute Velocity Vr1: Inlet Relative Velocity Vr2: Exit Relative Velocity Va2:Exit Absolute Velocity a1: Inlet flow Angle. b1: Inlet Blade Angle. b2: Exit Blade Angle. a2: Exit flow Angle.

Selection of The Velocity Triangles Ub Vr1 Va1 b1 a1 a2 b2 U Vr1 Va1 Vr2 Va2 b1 a1 a2 b2 Va2 U Vr1 Va1 Vr2 Va2 b1 a1 a2 b2 Vr2 U Vr1 Va1 Vr2 Va2 b1 a1 a2 b2 Va1: Inlet Absolute Velocity Vr1: Inlet Relative Velocity Vr2: Exit Relative Velocity Va2:Exit Absolute Velocity a1: Inlet flow Angle. b1: Inlet Blade Angle. b2: Exit Blade Angle. a2: Exit flow Angle.

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

Steam Volume Variation HP Range Specific volume, m3/kg Steam Path, Mpa

Steam Volume Variation IP Range Specific volume, m3/kg Steam Path, Mpa

Steam Volume Variation LP Range Specific volume, m3/kg Steam Path, Mpa

Bleeding for FWHs : A win-win Idea

Efficiency of USC Turbine Modules:800MW

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