Modes of Work Transfer P M V Subbarao Professor Mechanical Engineering Department I I T Delhi Development of Power for Different Needs!!!
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.
Types of Work Transfers Moving Boundary work (displacement work) Electrical work Shaft work Flowing fluid work
Moving Boundary work (displacement work) Boundary work occurs when a change in the system causes a force to act on the boundary and make it move.
Simple Processes for Displacement Work : Control Mass
Control Mass : Constant Volume & Pressure Processes
Displacement Work done by Superheated Steam During An Isothermal Process
Generalized Process in A Control Mass p = p 0 + k (V-V 0 ) p 2 = p 0 2 + k (V-V 0 ) 2 Polytropic Nature of Fluid Process: pV n = Constant –n: Polytropic constant. –n=0 : Constant Pressure Process. –n= : Constant Volume Process.
The Polytropic Process by A Control Mass One in which the pressure-volume relation is given as PV n =constant n may have any value from minus to plus infinity. Work transfer during a polytropic process.