mel346-3 (1)
TRANSCRIPT
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Fluid Dynamic Characterization of Turbo-machinery
P M V Subbarao
Professor
Mechanical Engineering Department
Understanding the Role of Vectorial analysis !!
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The thermodynamic Variations
IncompressibleFluid
CompressibleFluid
Power GeneratingMachines
Hydraulic Turbines Steam/Gas/windTurbines
Power ConsumingMachines
Pumps Fan/blowers/Compressors
Two main categories of turbo-machine are identified: Firstly, those which absorb power to increase the fluid
pressure or head (fans, compressors and pumps); Secondly, those that produce power by expanding fluid to
a lower pressure or head (hydraulic, steam and gasturbines).
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Fluid Dynamics of A Turbo-machine
A Turbo-machine
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The Ancient Design : Undershot Water Wheel : 4000BC
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SOME TYPES OF WIND TURBINES: VAWT
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SOME TYPES OF WIND TURBINES: HAWT
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Various Types of Modern Turbomachine
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Why so many different types of either pumps(compressors) or turbines are in use ?
Is it due to (almost) infinite range of service requirements?
As a fact, for a given set of operating/resourcerequirements ,
there should be only one type of pump or turbine which is best suited to provide best/optimum performance.
Why So Many?
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Classification of Turbo-machines
Two main categories of turbo-machine are identified: Firstly, those which absorb power to increase the fluid
pressure or head (fans, compressors and pumps); Secondly, those that produce power by expanding fluid to
a lower pressure or head (hydraulic, steam and gasturbines).
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Classification : Flow Path
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Solid Fluid Interaction Level
Open flow No casing or enclosure for the rotating device
Propeller is an open flow power consuming
device. Windmill is an open flow power generating
device.
Enclosed or encased flow devices
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Any Unified Theory?
Developed by the Father of Turbo- machines
The Mathematics of Turbo-machinery
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Leonhard Euler
Leonhard Euler (1707-1783) wasarguably the greatest mathematician ofthe eighteenth century.One of the most prolific writer of alltime; his publication list of 886 papersand books fill about 90 volumes.
Remarkably, much of this output datesfrom the last two decades of his life,when he was totally blind.Euler's prolific output caused atremendous problem of backlog: the St.Petersburg Academy continued
publishing his work posthumously formore than 30 years.
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Theoretical and Rigorous Work of French
Bernoulli and Leonhard Euler. 1750:Euler offered a memoir containing analysis and
equations for hydraulic turbines. 1754: An idealized theoretical application of Newtons
Law to centrifugal impellers. Known as Euler Equation.
Did much to help the development of hydraulic machinery. 1767: Relation between Torque and Change in moment of
momentum of the fluid as it passed through the machine.
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Applications of Eulers Equation
Euler equation applies to all kinds of turbomachines. Wind turbines ---- Pumps --- Gas turbines. Axial flow machines to Radial flow to Mixed flow.
Energy extraction machines Energy consumingmachines. For a turbine the value of Equation is negative. For pumps, fans, blowers and compressors it is positive.
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The Superiority of Vector Parameters
k V jV iV V z r
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