1. P M V Subbarao Professor Mechanical Engineering Department
Thermodynamics of High Temperature Steam Generation in an Open System (Control Volume)
P M V Subbarao
Professor
Mechanical Engineering Department
Economy of Creation of High Temperature in a Cycle…..

2. Steam Generation : Closed System Vs Open System

3. Energy transport by Moving fluid
Amount of energy transport by a moving fluid of mass m is defined as methalpy and denoted by:
Q = mθ = m ( h + ½V2 + gz )
Rate of Energy Transport:

4. Clues to Generate High Economy and Eco-friendly Steam

5. Economics of Flow Steam generation

6. Constant Pressure Steam Generation Process
Theory of flowing Steam Generation

7. Creation of High Temperature @Constant Pressure Steam Generation Process

8. Economics of Flow Steam generation
Supercritical Steam Generation
Subcritical Flow Boiling
Pump Exit

9. Selection of Steam Generation Pressure in A Rankine Cycle
T C
v, m3/kg

10. Entropy, x=s : A Measure of State of Matter
So (J/K•mol)
H2O(liq) 69.95
H2O(gas) 188.8
For a given substance
S (gaseous state) > S (liquid state) > S (solid state)

11. Entropy and Order of Molecules of Matter
S˚(Br2 liq) < S˚(Br2 gas)
S˚(H2O solid) < S˚(H2O liquid)

12. Entropy, S : Molecular Complexity
Increase in molecular complexity generally leads to increase in S.

13. Standard Molar Entropies

14. Entropy and Temperature
S increases slightly with T
S increases a large amount with phase changes

15. Entropy Change during a Reversible Process
From the definition of the entropy, it is known that Q=TdS during a reversible process.
The total heat transfer during this process is given by Qreversible =  TdS
Therefore, it is useful to consider the T-S diagram for a reversible process involving heat transfer T S
On a T-S diagram, the area under the process curve represents the heat transfer for a reversible process
A reversible adiabatic process

16. Process : h-s Diagram : Mollier Diagram
Enthalpy-entropy diagram, h-s diagram: it is valuable in analyzing steady-flow devices such as turbines, compressors, etc.
Dh: change of enthalpy from energy balance (from the first law of thermodynamics)
Ds: change of entropy from the second law.
A measure of the irreversibilities during an adiabatic process. Ds Dh h s

17. Enthalpy Vs Entropy Diagram

18. Constant Pressure Steam Generation Process
Theory of flowing Steam Generation
Constant Pressure Steam Generation:
A clue to get high temperature with same amount of burnt fuel

19. Steam Generation : Expenditure vs Wastage
Vapour
h mfuel
Liquid +Vapour
Liquid x

20. Steam Generation At High Pressure
x=s

21. Analysis of Steam Generation at Various Pressures
Specific
Pressure
Enthalpy
Entropy
Temp
MPa
kJ/kg
kJ/kg/K C 1
3500
7.79
509.9 2 5
7.06
528.4 3 10
6.755
549.6 4 15
6.582
569 20
6.461
586.7 6 25
6.37
602.9 7 30
6.297
617.7 8 35
6.235
631.3

22. Fuel Savings during Steam Generation
Specific
Temp
Pressure
Enthalpy
Entropy C
MPa
kJ/kg
kJ/kg/K
575 5
3608
7.191 10
3563
6.831
12.5
3540
6.707 15
3516
6.601
17.5
3492
6.507 20
3467
6.422
22.5
3441
6.344 25
3415
6.271 30
3362
6.138 35
3307
6.015

23. Law of Nature Behavior of Vapour at Increasing Pressures
Reversible nature of substance at a given temperature
All these show that the irreversible behavior of a fluid decreased with increasing pressure.

24. Reduction of Wastage

25. Less Fuel for Creation of Same Temperature

26. The Training for High Altitude Trekking