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Rothalpy Based Design of Turbines. P M V Subbarao Professor Mechanical Engineering Department I I T Delhi. A Design Philosophy through Accounting/Balancing/ Conservation …. Conservation of Rothalpy.
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Rothalpy Based Design of Turbines P M V Subbarao Professor Mechanical Engineering Department I I T Delhi A Design Philosophy through Accounting/Balancing/ Conservation ….
Conservation of Rothalpy A cornerstone of the analysis of steady, relative flows in rotating systems has, for many years, been the immutable nature of the fluid mechanical property rothalpy. "In a moving passage (Flow Path) the rothalpy is therefore constant provided: the flow is steady in the rotating frame; no friction from the casing; there is no heat flow to or from the flow. or
Clues for Creation of Basic Variations in Fluid Flow Paths Infusion of more Euler concept: Ideas for creation of a variety in turbo-machine.
Blade Velocity Vs Tangential Component of Fluid Velocity Ub Ub In maridional plane at mean radius of rotor Vi Vri Vfi Vai
Vi Variations in Inlet Flow Geometry Vri Vfi Vai Vi Vri Vi Vai Ub Vfi Ub Ub Vfi Vri Vai
Relative Angular Velocity Constant in an ideal turbo-machine
Behavior of Fluid along Flow Paths in Stator Vs Rotor For stator Ublade =0 For rotors : For a true axial flow machines: Ubladeconstant throughout the flow path
Blade Velocity Vs Tangential Component of Fluid Velocity Ub Ub In maridional plane at mean radius of rotor & inlet Vi Vri Vfi Vai
V i Vri Vfi Vai V i Vri V i Vai Ub Vfi Ub Ub Vfi Vri Vai
Relative Angular Velocity Constant in an ideal turbo-machine
Classification of Isentropic Expansion Paths For stator path : Ublade =0 For rotor Paths : For a true axial flow rotor paths: Ublade constant
Turbo-machines working with Vapors/Gas For an ideal gas:
Turbo-machines working with Perfect Gas For simple compressible fluid: Like Inert Gas
From Books of Sir Charles Parson • In 1884 or four years previously, I dealt with the turbine problem in a different way. • It seemed to me that moderate surface velocities and speeds of rotation were essential if the turbine motor was to receive general acceptance as a prime mover. • I therefore decided to split up the fall in pressure of the steam into small fractional expansions over a large number of turbines in series, so that the velocity of the steam nowhere should be great. • A moderate speed of turbine suffices for the highest economy.
This principle of compounding turbines in series is now universally used in all except very small engines, where economy in steam is of secondary importance. • The arrangement of small falls in pressure at each turbine also appeared to me to be surer to give a high efficiency. • The steam flowed practically in a non-expansive manner through each individual turbine, and consequently in an analogous way to water in hydraulic turbines whose high efficiency at that date had been proved by accurate tests.
Enthalpy How to Execute Conservation of Rothalpy ?? Kinetic Energy Velocity Vector Field Fluid Dynamics Generation of Change in rate of angular momentum (An Action) Shaft Torque is the final need as Reaction Who Will take the Reaction ???