1. Sinhgad Technical Education Society’s
Sou. Venutai Chavan Polytechnic Pune
THERMAL ENGINEERING
Second Year Mechanical
Mr. D. A. Kamble
(ME Mech. Design Engg.)
2. Second Law of Thermodynamics
• Kelvin plank statement-
It is impossible to construct an engine working in a cyclic process, whose sole effect
is to convert all heat supplied into equal work.
• Clausious statement-
It is impossible to construct a device working in a cyclic process whose sole effect
is to transfer heat from low temperature body to high temperature body.
5. Factors Making Process Irreversible
Friction- The friction that converts the energy of the fuel to heat energy
Heat transfer through finite temperature difference- The unrestrained expansion of the
fluid which prevents from regaining the original form of the fuel Heat transfer through a
finite temperature, reverse of which is not possible as the forward process, in this case, is
spontaneous
Free Expansion- Mixing of two different substances which cannot be separated as the
process of intermixing is again spontaneous in nature, the reverse of which is not
feasible.
6. Steady Flow Energy Equation
Assumption-
1. Mass flow rate at both points is constant.
2. Rate of HT is constant.
3. Rate of work transfer is constant
4. No change in chemical composition.
