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…

Process Executed by A Control Volume

Process Executed by A Control Volume

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

Control of Manufacturing Process

Thermodynamic Processes for Metal Cutting

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

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?

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.

Justification of Work during Metal Cutting

Displacement Work : Dangerous & Inhuman Technologies

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.