1. Thermodynamic Description of A Manufacturing Process
P M V Subbarao
Professor
Mechanical Engineering Department
I I T Delhi
Mathermatical description of Change during a Manufacturing Process…

2. Process Executed by A Control Volume

3. Process Executed by A Control Volume

4. Thermodynamic Process
During a quasi-equilibrium or quasi-static process, the system remains practically in equilibrium at all times.
Quasi-equilibrium work-producing devices deliver the maximum work.
Theoretical description of processes is possible by keeping any one thermodynamic property may be held constant.
Process Property
isobaric pressure
isothermal temperature
isochoric volume
Adiabatic No Heat Transfer

5. Control of Manufacturing Process

6. Thermodynamic Processes for Metal Cutting

7. Thermodynamic Cycle
A process (series of connected processes) with identical end states.
When a system in a given initial state goes through a number of different changes of state or processes and finally returns to its initial state, the system has undergone a cycle.
At the conclusion of a cycle, all the properties have the same value they had at the beginning.
Cyclic Working of Left Ventrical

8. What happens When there is a change in state?
Any of these happenings is/are useful for engineering world?
Does it consume any resource?
How to recognize these Happenings?
Thermal In-equilibrium
Mechanical In-equilibrium
Chemical In-equilibrium
Any combinations of above.
These are happenings or actions or path functions or interactions.
Present only during a change of state.
What action is work transfer?
What action is Heat transfer?
What action is Mass transfer?
How to differentiate?

9. Mechanical Work Tranfer
Work is a mechanical concept given by the expression:
F is a force and s is a displacement
Work is a scalar product
Force components along the displacement vector only can do work
Force components perpendicular to the displacement vector cannot do work.
This relationship will be useful to find work required to raise a weight, to stretch a wire or to move a charged particle through a magnetic field.

10. Justification of Work during Metal Cutting

11. Displacement Work : Dangerous & Inhuman Technologies

12. A Need for More General Definition of Work
As an English army officer, Thomas Savery was once ejected from the Lord of the Admiralty's office as a lunatic because he proposed a ship that could be propelled by side-mounted wheels rather than by wind or oars.
He exhibited great fondness for mechanics, and for mathematicians natural philosophy and gave much time to experimenting, to the contriving of various kinds of apparatus, and to invention.