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Initial Designs of Turbines

Initial Designs of Turbines. P M V Subbarao Professor Mechanical Engineering Department I I T Delhi. Basic Models for Harvesting of Fluid Energy …. Basic Rules for Design of An Ideal Turbine Flow Path. Create highest usable form of a resource.

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Initial Designs of Turbines

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  1. Initial Designs of Turbines P M V Subbarao Professor Mechanical Engineering Department I I T Delhi Basic Models for Harvesting of Fluid Energy ….

  2. Basic Rules for Design of An Ideal Turbine Flow Path • Create highest usable form of a resource. • Creation of initial velocity/kinetic energy using Stator. • X1 (Impulse)+X2(Reaction)+(1-X1-X2)(centripetal) • Y1 (Radial)+(1-Y1 )(Axial) • Design of Flow Path using Conservation of rothalpy. • Design blade cascade using conservation of mass and momentum. • A design of an Ideal Machine ….. • Each stage can do finite amount of action….!!! • Many stages are needed to complete the action….

  3. Advanced 700 8C Pulverised Coal-fired Power Plant Project

  4. Some Facts about Advanced Steam Turbines

  5. Increased Magnitudes of Forces

  6. de Laval Turbine : The First Design for Steam Turbine • de Laval turbine is an impulse turbine : An enormous velocity (30,000 revolutions per minute in the 5 H. P. size) is requisite for high efficiency, and the machine has therefore to be geared down to be of practical use.

  7. Classification of Steam Turbine Flow Paths

  8. Classification of Steam Turbine Flow Paths

  9. Classification of Steam Turbine Flow Paths

  10. Classification of Steam Turbine Flow Paths

  11. The First Proposal onInfrastructure for Realization of Newton's’ Laws Stator Rotor

  12. Axial Turbine Stator Exit/Rotor Inlet Velocity Triangle Va1 Va1 Vw1 Vr1 a1 a1 Vw1 b1 Vf1 Vf1 Va0 Vf0

  13. U Vr1 Va1 Va1 Inlet Velocity Triangle Vr1 U U Va2 Vr2 Exit Velocity Triangle Vr2 Kinematics of Flow Past A Rotor Blade

  14. U b1 a2 a1 b2 Va1 Va2 Vr1 Vr2 Va1: Inlet Absolute Velocity Vr1: Inlet Relative Velocity Vr2: Exit Relative Velocity Va2:Exit Absolute Velocity a1: Inlet Nozzle Angle. b1: Inlet Blade Angle. b2: Exit Blade Angle. a2: inlet Nozzle Angle (next stage). Isentropic Impulse Rotor

  15. U b1 a2 a1 b2 Va1 Va2 Vr1 Vr2 Newton’s Second Law for an Impulse Blade: The tangential force acting on the jet is: F = mass flow rate X Change of velocity in the tangential direction Change in velocity in tangential direction: -Vr cos(b2) – Vr cos(b1). - Vr(cos(b2) + cos(b1)). Tangential Force,

  16. The reaction to this force provides the driving thrust on the wheel. The driving force on wheel Power Output of the blade : Diagram Efficiency or Blade efficiency:

  17. U a2 a1 b2 b1 Va1 Va2 Vr1 Vr2 Power Output of the blade : For impulse blading with isentropic flow For blading with frictional flow

  18. U a2 a1 b2 b1 Va1 Va2 Vr1 Vr2

  19. For a given shape of the blade, the efficiency is a strong function of U/Va1, called blade speed ratio, f

  20. U a2 a1 b2 b1 Va1 Va2 Vr1 Vr2 Condition for maximum efficiency: Maximum efficiency:

  21. Availability of Steam for Condenser Temperature of 450C

  22. Classification of Steam Turbines

  23. The most powerful steam turbine-generator in the world at the time of it's construction:1903 Built in 1903, the 5,000-kilowatt Curtis steam turbine-generator was the most powerful in the world. It stood just 25 feet high, much shorter than the 60 feet reciprocating engine-generator of a similar capacity

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