1. Analysis of Rankine Cycle with FWH P M V Subbarao Professor Mechanical Engineering Department I I T Delhi Engineering solution to Pure Thoughts..…..

2. Regeneration Cycle with Open FWH

3. Analysis of OFWH h3h3 h6h6 y h2h2 1-y Conservation of energy:

4. Haywood Methodology Analysis of Engineering Cycles : R.W. Haywood PBPB

5. Assumptions : 1.The Difference between local steam enthalpy and enthalpy of saturated water at the same pressure is constant throughout the expansion. 2.Constant ‘β’ Assumption by Haywood. By assuming that the turbine expansion line follows a path on the diagram such that the (h-h f )=constant= β Where, h- local enthalpy on the turbine expansion line at a given pressure. h f =Enthalpy of saturated water at that pressure.

6. Let the enthalpy rise of feed water in the heater is . 4f4f

7. 4f4f Maximum irreversibility to be eliminated = The total enthalpy rise of feed water = h 4f – h 1 Let

8. 4f4f Pump work input is negligible

9. There fore the efficiency can be written as Here β and α are fixed and  is variable. So, there is an optimum value of γ for which η is a maximum. On differentiation, There fore  = α / 2 The cycle efficiency is maximum when the total enthalpy rise of feed water (h 4f – h 1 ) from the condenser temperature to the boiler saturation temperature is divided equally between the feed water heater and the economizer ( i.e. h 4f – h 4 = h 3 – h 2 ) in a single bleed cycle.

10. So the temperature rise in the feed water heater is ΔT = ½ ( T boiler saturation – T condenser ) And the corresponding cycle efficiency is For a non-regenerative cycle,

11. The maximum gain in efficiency due to regeneration This is positive. This shows that the cycle efficiency has improved due to regeneration.

12. Location of Haywood’s Optimum OFWH h3h3 h6h6 y h2h2 1-y

13. Analysis of Regeneration through OFWH

17. Analysis of Bleed Steam Performance p bleed, MPa

18. Analysis of Condensing Steam Performance p bleed, MPa

19. Comparison of Performance of Bleed & Condensing steams P regen, MPa  cond  bleed

20. Performance of FWH Cycle p regen, MPa  total ~ 12MPa

21. Performance of bleed Steam p regen, MPa  bleed ~ 2 Mpa

22. w bleed Workoutput of bleed Steam p regen, MPa ~ 12MPa

23. Fractional specific output Workoutput of bleed Steam Fraction of Bleed Steam

24. w bleed Workoutput of bleed Steam

25. Progress in Rankine Cycle Year 1907 19191938195019581959196619731975 MW52030601202005006601300 p,MPa1.31.44.16.210.316.215.9 24.1 T h o C260316454482538566 565538 T r o C-- 538 566565538 FHW--23466788 Pc,kPa13.55.14.53.43.7 4.45.45.1 ,% --~1727.630.535.637.539.839.540