An overview of ETD Syllabus

1. Engineering Thermodynamics
An Overview
Date: 25 Sep 2021
A Presentation by:
Mr. R.L. SANKARLAL,
Asst. Professor (Gr-II) /Mech.,
R.M.K. Engineering College

2. Unit – I Basic concepts & I law of TD
1.Thermodynamic Systems
2.Properties – Intensive & Extensive, Perfect Gas Equation
3.Heat (Q) Vs Work (W)
4.Property, State, Process & Cycle in Property Diagram
5.Processes – Non-flow Processes, Flow Processes
6. First Law of Thermodynamics for Cyclic Process, PMM-I.
7.First Law of Thermodynamics for Non-Process & Flow
Processes (SFEE)

3. 3
Key Take away Points… (Recap)
• Processes – Reversible & Irreversible.
• Quasi-static Process is a reversible process (slowest)
and difficult to achieve.
• Cycle – Open Cycle & Closed Cycle
• Point Function & Path Function
• Introduction to thermodynamic properties
– P-V-T Relations

4. Cyclic Process or Cycle
Thermodynamic cycle is defined as a series of change of
states occurs such that the final state is identical with the
initial state.
4

5. Point Function and path function
5

6. 6

7. 7
PRESSURE
The normal stress (or “pressure”) on the feet
of a chubby person is much greater than on
the feet of a slim person.
Some basic
pressure
gages.
Pressure: A normal force exerted by a
fluid or any substance per unit area
68 kg 136 kg
Afeet=300cm2
0.23 kgf/cm2 0.46 kgf/cm2
P=68/300=0.23 kgf/cm2

8. 8
TEMPERATURE AND THE ZEROTH LAW OF THERMODYNAMICS
• The zeroth law of thermodynamics: It states that.” When two
systems are separately in thermal equilibrium with a third system,
the they themselves are in thermal equilibrium with each other.

9. Important Thermodynamic Properties
• Pressure(p), Volume(V), Temperature(T)
– P-V-T Relations for a process, (p1V1) / T1 = (p2V2) / T2
• Internal Energy – Total I.E (U) & Sp. I.E (u)
– U = m.Cv.T or u = Cv.T, U = m.Cv.T or dU = m.Cv.dT
– It is the energy possessed by a body or substance in terms of
heat, when the molecules or atoms at constant volume.
• Enthalpy – Total Enthalpy (H) & Sp. Enthalpy (h)
– H = m.Cp.T or h = Cp.T, H = m.Cp.T or dH = m.Cp.dT
– Also, H = U+pV or h = u+pv – Sum of Internal Energy & Work of
Expansion.
– It is the Total Heat Content of a substance, includes the work of
expansion
9

10. Important Thermodynamic Properties
• Entropy (S) – (dQ/T) – Heat Transfer at a specific temperature.
– Change in Entropy (ds) is more significant than absolute
Entropy(s)
– Measure of molecular randomness or disorder.
• Heat(Q) or Heat Transfer (Q) - Energy transfer in terms of
Heat
–  Q = m.Cp. T
• Work or Work Transfer (W)
– Any transfer of energy which is convertible into raising or
lowering of weight.
– Modes of work - Displacement work, Shaft Work, Paddle
Wheel Work, electrical work, work in stretching a wire etc.
10

11. Sign convention
11
System
+ Q
+ W
- W
- Q

12. Heat Vs Work – Comparison
12

13. FIRST LAW OF
THERMODYNAMICS
13

14. 1
1-2-1 A cycle
2
Closed System
( Non-flow Processes)

15. e
Ce
i Shaft
Ci dW
ze
zi
Steady flow device
Open Systems
(Flow Processes)
( First law of TD as SFEE)

16. Unit – II Second Law & Entropy
1.Source, Sink
2.Second Law as per Kelvin-Plank (Engine), Clausius (Refrigerator)
3.Heat (Q), Work (W), Efficiency, COP.
4.Ideal Engine Vs Actual Engine. (Carnot’s Statements)
5.Relationship between Efficiency of Engine, COP of Refrigerator & HP.
6.Entropy Definition
7.Irreversibility & Entropy.
8. Principle of Increase of Entropy
9.Availability & Unavailability

17. Cold Reservoir
Hot Reservoir
Engine, Refrigerator & Heat Pump

18. Unit – III Steam Generation & Properties
1.Sensible Heat Vs Latent Heat
2.Steam Formation, Types of Steam
3.Dryness Fraction, Wetness Fraction
4.Properties of Steam in Steam Tables, h-s Diagram(Mollier Diagram)
5.Rankine Cycle, Adiabatic/Isentropic Expansion in Turbine.
6.Methods to improve efficiency of Rankne Cycle
7.Reheat Cycle, Regenerative Cycle.
8. Reheaters & Staging the expansion & Steam tapping
9.Representation of the above in Mollier Diagram

19. Unit – IV Thermodynamic Relations
1.Ideal vs Real Gases, Vander Waal’s Equation
2.Gibbs Function, Helmotz Function, Maxwells
Relations, TdS Equations
3.Compressibility Factor(z), Compressibility Chart
4.Clausius Clayperon Equation
5.Joule Thompson Experiment

20. Unit – V Psychrometry & Gas MIxtures
General Definitions:
• Dry Air
• Moist Air
• Humidity
• Saturated Air
• Dew / Mist /Frost / Fog
Phychrometric Properties:
Dry Bulb Temperature - DBT
Wet Bulb temperature – WBT
Wet Bulb Depression - WBD
Dew Point Temperature – DPT
Absolute Humidity / Specific Humidity / Humidity Ratio
Relative Humidity
Specific Enthalpy
Specific Volume
1. Mixing of air streams
2. Sensible heating
3. Sensible cooling
4. Cooling and dehumidification
5. Cooling and humidification
(Evaporative Cooling)
6. Heating and dehumidification
7. Heating and humidification.
Psychrometric
Processes
Gas Mixtures
1. Daltons Law of Partial Pressure
2. Amagat’s Law of Partial Volume.
3. Mass Fraction & Mole Fractions

21. Psychrometric Chart

24. Questions, Queries
& Discussions