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Thermodynamic Work

Thermodynamic Work. P M V Subbarao Professor Mechanical Engineering Department I I T Delhi. Civilized methods for manufacturing works!!!. Definition of Thermodynamic Work.

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Thermodynamic Work

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  1. Thermodynamic Work P M V Subbarao Professor Mechanical Engineering Department I I T Delhi Civilized methods for manufacturing works!!!

  2. Definition of Thermodynamic Work • Positive work is done by a system, during a given process, when the sole effect external to the system could be reduced to the rise of a weight. • This definition may appear arbitrary. • This is enforced on the readers/users to identify all possible work actions in engineering.

  3. Discussion of the Definition • Positive work is done by a system, during a given process, when the sole effect external to the system could be reduced to the rise of a weight. • Rise of weight is obviously work. • Sole Effect: Entire effect (100 %) • External: Only at the boundary or magnitude depends on the boundary • Could be reduced to: It need not be just rise of weight. Any thing that can be translated into to rise of weight. • Will it consider Mechanical work?

  4. Mechanical Work Generating System

  5. S Positive work is done by a system, during a given process, when the sole effect external to the system could be reduced to the rise of a weight. Mechanical work System Before triggering Surroundings F After triggering

  6. h Thermodynamic Work W W Mechanical Work is Thermodynamic work and vice versa.

  7. Broader Applications of the Thermodynamic Work Convector What Action is present at this boundary? Battery

  8. Rise W Equivalence of Raising of A Weight

  9. Hot copper An Unknown Action Turbine Generator Convector

  10. Negative Work • When a system does positive work, its surroundings do an equal quantity of negative work. • Conversely, when surroundings do positive work, the system does and equal quantity of negative work.

  11. Types of Work Transfers • Moving Boundary work (displacement work) • Extrusion • Metal cutting • Forging • Electrical work • Shaft work • Flowing fluid work

  12. Displacement work : Extrusion • Extrusion is the process by which a block/billet of metal is reduced in cross section by forcing it to flow through a die orifice under high pressure. • Most metals are hot extruded due to large amount of forces required in extrusion.

  13. Thermodynamic Process for Extrusion

  14. Simple Processes for Displacement Work

  15. Study of Pressure-Volume Diagrams. • The rapid rise in pressure during initial ram travel is due to the initial compression of the billet to fill the extrusion container. • For direct extrusion, the metal begins to flow through the die at the maximum pressure. • This pressure is called as the breakthrough pressure. • • As the billet extrudes through the die the pressure required to maintain flow progressively decreases with decreasing length • of the billet in the container. • • At the end of the stroke, the pressure rises up rapidly and it is usual to stop the ram travel so as to leave a small discard in the container.

  16. Innovative Design to modify Pressure volume Diagram

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