Power Generation as An Scientific Engineering By P M V Subbarao Mechanical Engineering Department I I T Delhi Development of Scientific Methods for Conversion of A Resource into Useful Form!!!!

The Family of Steam Engines A Direct Hardware Solutions to the Essential Need thru Natural Philosophy…..

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. 1821: Carnot began the work which led to the mathematical theory of heat and helped start the modern theory of thermodynamics. 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.

James Watt’s Engine : The Hardware Subjected for Mathematical Modeling James Watt radically improved Newcomen's engine (1769) by condensing the steam outside the cylinder.

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 – 1823 : Carnot attempted to find a mathematical expression for the work produced by one kilogram of steam. 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 stage and an isothermal stage in which work is consumed : Réflexions sur la puissance motrice du feu et sur les machines propres à développer cette puissance which includes his description of the "Carnot cycle".

A Mathematical Model for (James Watt’s) Steam Engine expansion Heat Addition Heat Removal

Layout for A Power Generation System : Thermodynamic Cycles Goal: To generate electricity from heat input!!!

Carnot’s Theoretical Model for Engine A B C

Modern Thermodynamic Description of Carnot Model for Power Generation System

Carnot Power Cycle

Analysis of Cycle A Cycles is a Control Mass : Constant Mass Flow Rate First law per cycle:  Q i =  W i Q b +Q c = W t +W c W net(cycle) = Q net(cycle) = Q b +Q c W net(cycle) = Q net(cycle) = T 2 (S 3 -S 2 ) + T 1 (S 1 -S 4 ) But, S 1 = S 2 & S 3 = S 4 W net = (T 2 - T 1 ) (S 3 -S 2 ) = (T 2 - T 1 )  S Q b = T 2 (S 3 -S 2 ) = T 2  S

Efficiency of the cycle = net work/heat input Other performance parameters: Specific work output : w net = (T 2 - T 1 )  s

 inimize the capital & running costs. Compact and efficient. Design of Tecno-economically Optimal Plant

Feasibility of A Model under Irreversible World Mean Effective Pressure = Work done per unit volume of engine

A Major Crossroad Confusion: How to go from <6% to 75% Efficiency ???????

Final Observation about Carnot Theorem.

Rankine, William John Macquorn ( )

A MANUAL of the STEAM ENGINE and other PRIME MOVERS 1859 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 his work is named as " 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.

Rankine, William John Macquorn ( ) 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. 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.

Parson Turbine working on Rankine Cycle

Dissection of Ideal Rankine Cycle

Constant Pressure Steam Generation Process Constant Pressure Steam Generation: =0 Theory of flowing Steam Generation