What is an Irreversible process?
Before understanding an irreversible process let us first understand a reversible process.
Now it is obvious that a process which is not reversible is an irreversible process.
Practically all the processes are irreversible processes.
Causes of irreversibility in a process
- Lack of thermodynamic equilibrium
- Mechanical equilibrium
- Chemical equilibrium
- Thermal equilibrium
- Dissipative effects
Examples of dissipative effects are Mechanical friction, Fluid viscosity, Magnetic hysteresis, Inelasticity, Electrical resistance etc.
As mentioned earlier that a process can never be reversible but it can be in the limit.
Below is a comparison between a complete reversible process and a process reversible in the limit.
|Process||Perfectly reversible process||Process reversible in the limit|
|Mechanical work transfer||ΔP = 0||ΔP → 0|
|Heat transfer||ΔT = 0||ΔT → 0|
|Mass transfer||ΔC = 0||ΔC → 0|
|Chemical reaction||Δµc = 0||Δµc → 0|
P = Pressure
T = Temperature
C = Concentration
µc = Chemical potential
Featured image source: By Ian Alexander – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=65736980