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Analysis of Power Plant : A Scientific Engineering. P M V Subbarao Professor Mechanical Engineering Department. An Exclusive Engineering Science for Extrasomatic Needs ……. The Family of Steam Engines. A Direct Hardware Creations to the Essential Need ….
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Analysis of Power Plant : A Scientific Engineering P M V Subbarao Professor Mechanical Engineering Department An Exclusive Engineering Science for Extrasomatic Needs ……..
The Family of Steam Engines A Direct Hardware Creations to the Essential Need …..
Generation of Shaft Work Energy transmission with a rotating shaft is very common in engineering practice. A force F acting through a moment arm rs,p generates a torque T of
Michael Faraday • In 1820, in arguably the most pivotal contribution to modern power systems. • Michael Faraday and Joseph Henry invented a primitive electric motor. • In 1831, documented that an electric current can be produced in a wire moving near a magnet—demonstrating the principle of the generator.
The Birth of Power Plant • In 1882 the world's first coal-fired public power station, the Edison Electric Light Station, was built in London. • This was a project of Thomas Edison organized by Edward Johnson. • A Babcock & Wilcox boiler powered a 125-horsepower steam engine that drove a 27-ton generator. • This supplied electricity to premises in the area that could be reached through the culverts of the viaduct without digging up the road, which was the monopoly of the gas companies. • The customers included the City Temple and the Old Bailey. • Another important customer was the Telegraph Office of the General Post Office, but this could not be reached though the culverts. Johnson arranged for the supply cable to be run overhead, via Holborn Tavern and Newgate.
Pearl Street Station Thomas Edison in September 1882 achieved his vision of a full-scale central power station
Infusion of Analytical Ideas into Power Plant Development • Sir James Watt is an ingenious engineering scientist, who carried out most useful hardware research and development. • He was not aware of many of the thermodynamic quantities. • Later engineers used Charles and Boyle laws in sizing of cylinder. • Prof. James Black carriedout research to determine specific heats of steam and water. • There was a gradual infusion of analytical and theoretical research into basic hardware development. • Analytical methods helped in removal of uncertainty in engine operation. • Many theoreticians got motivated to work on theory of James Watt Engine.
Sadi Nicolas Léonard Carnot • 1814: After graduating, Carnot went to the École du Génie at Metz to take the two year course in military engineering. • 1819: Carnot began to attend courses at various institutions in Paris. • The problem occupying Carnot was how to design good steam engines. • Steam power already had many uses - draining water from mines, excavating ports and rivers, forging iron, grinding grain, and spinning and weaving cloth - but it was inefficient.
Carnot’s Thinking • It irked Carnot particularly that the British had progressed so far through the genius of a few engineers who lacked formal scientific education. • British engineers had also accumulated and published reliable data about the efficiency of many types of engines under actual running conditions. • They vigorously argued the merits of low- and high-pressure engines and of single-cylinder and multi-cylinder engines. • 1822 – 1823 : Carnot attempted to find a mathematical expression for the work produced by one kilogram of steam. • This work led to the mathematical theory of heat and helped start the modern theory of thermodynamics.
The Quintessential Novelty • 1824 : Réflexions sur la puissance motrice du feu et sur les machines propres à développer cette puissance which includes his description of the; • “ Mathematical Model for Carnot cycle". • Carnot's work is distinguished for his careful, clear analysis of the units and concepts employed and • for his use of both an adiabatic working stageand an isothermal stage in which work is consumed.
Hardware Cycle to A Thermodynamic Cycle Coal (Resource) The power (Need)
The Thermodynamic Cycle Burn Coal (to add Heat slowly) The Work (Move piston slowly)
Impact of Heat & Work Transfers on Steam • How to quantify the changes in steam due to work and heat transfer? • Human experts depended on their senses to define these changes. • Out of Five senses, Three senses could not quantify/recognize these changes. • Only two senses could quantify these changes: • Vision : Volume (m3) • Touch : Pressure (kPa) and Temperature (C or K) • None of the above are equivalent to heat or work. • There must be a relation between these properties and heat & work.
Carnot Model for Gas Engine • Maximum Power : 17BHP@8500 RPM • Maximum Torque :15Nm@7500 rpm
Cost to Benefit Ratio of Carnot Model • Work/power developed by the engine is the benefit. • Fuel mining, transportation, processing incur cost. • It is essential to develop a cost to benefit ratio. • The thermodynamic version of this ratio is named as efficiency.
All Substance Give the Same Efficiency • Engines had been proposed and constructed using working substances other than water, with no dramatic improvement in efficiency. • Carnot reasoning implies that : to the extent that is it possible to eliminate frictional losses and other sources of inefficient operation, all substances will do the same work for the same temperatures of operation. • All these situations led to the development of Ideal model for engine using Adiabatic and isothermal processes. • He could get an expression for efficiency independent of substance only through this model.
A Major Crossroad Confusion: How to go from <6% to 70% Efficiency ???????
A Major Crossroad Confusion: How to go from <6% to 75% Efficiency ???????
A Manual of the Steam Engine and Other Prime Movers (1859)William John Macquorn Rankine • This law (regarding the theoretical efficiency of heat engines by Mr. Joule), • and the law of the maximum efficiency of heat engines, • are particular cases of a general law which regulates all transformation of energy, and • is the basis of the Science of Energetics.
A MANUAL of the STEAM ENGINE and other PRIME MOVERS 1859 Rankine • The conventional name “work of the thermodynamics ” by Rankine. • Rankine is the largest meritorious person who in addition raises the technology of the steam engine to science, the word, "energy " is something due to him. • Harmony meaning of this work becomes " the manual of the steam engine and the other motive for action machines “. • The chapter " of thermodynamics " advocated the cyclic process which is called Rankine cycle. • This was related to the policy of researching the steam engine theoretically, brought the progress of the steam engine.
Rankine, William John Macquorn(1820-1872) • In 1849 he delivered two papers on the subject of heat, and in 1849 he showed the further modifications required to French physicist Sadi Carnot's theory of thermodynamics. • In A Manual of the Steam Engine and other Prime Movers 1859, Rankine described a thermodynamic cycle of events (the Rankine cycle). • This came to be used as a standard for the performance of steam-power installations where a considerable vapour provides the working fluid. • Rankine here explained how a liquid in the boiler vaporized by the addition of heat converts part of this energy into mechanical energy when the vapour expands in an engine. • As the exhaust vapour is condensed by a cooling medium such as water, heat is lost from the cycle. • The condensed liquid is pumped back into the boiler.
How about a modified cycle - A Rankine cycle • To avoid transporting and compressing two-phase fluid, try to condense all fluid exiting from the turbine into saturated liquid before compressed it by a pump. • when the saturated vapor enters the turbine, its temperature and pressure decrease and liquid droplets will form by condensation. s • These droplets can produce significant damages to the turbine blades due to corrosion and impact. • One possible solution: superheating the vapor. • It can also increase the thermal efficiency of the cycle.
