1. Power Consuming Turbo-machines
P M V Subbarao
Professor
Mechanical Engineering Department
I I T Delhi
An expenditure of earnings….

2. Major equipment in A Power Plant

3. Structure of A Modern Power Plant

4. Pump services in Main Steam Cycle
Turbogenerator and auxiliaries
Condenser circulating pumps
Screen wash-water pumps
Cooling tower make-up pumps
Steam generator equipment
Condensate pumps
Condensate booster pumps
Boiler-feed pumps
Boiler-feed booster pumps
Deaerator make-up pumps
Heater drain pumps (low and high pressure)

5. Thermodynamic Cycle of air & Gas and flow diagram

6. Cross-section, single 65,000 hp boiler feed pump, 1300 MW fossil power plant

7. Expectations from A CondensatePump
Duty: Generate Required Open Feed water Heater Conditions !
Condensate Pump
Hot Well
Rhyd,1
Rhyd,2
Rhyd,n
pOFWH+ploss
OFWH

8. Expectations from A Boiler Feed Pump
To Generate Required Live Steam Conditions !
plive steam
Steam Turbine
Rhyd,1
Rhyd,SG
Rhyd,n
ploss+plive water
BF Pump
OFWH

9. Expectations from ID&FD Fan System

10. Layout of A General Pump

11. Basic Erection of A Pump
STATIC
SUCTION
HEAD

12. Basics of A fan

13. Water Flow Path in A Pump
                                                                        

14. Variation of Absolute Pressure inside A Pump
pabsolute
Flow Path

15. Cavitation
As the liquid flows onto the impeller of the pump it is accelerated and initially its pressure falls (Bernoulli).
The pressure subsequently increases as the fluid leaves the impeller and as the kinetic energy is recovered in the volute chamber.
If the pressure of the liquid falls below the vapour pressure, pv, the liquid boils, generating vapour bubbles or cavities-cavitation.
The bubbles are swept into higher pressure regions by the liquid flow, where they collapse creating pressure waves and cause mechanical damage to solid surfaces.
Moreover, pump discharge head is reduced at flow rates above the cavitation point.
Operation under these conditions is not desirable and damages the equipment.

17. NPSH
NPSH

18. Loss of NPSH

19. Available NPSH At Site Kinetic power mVs2/2
Frictional loss in suction piping

20. Classification of Pumps

21. Machine-Fluid Matching Parameter:
For fans
For Pumps

22. DIMENSIONAL ANALYSIS Scale model to prototype design and analysis.
Used to select proper turbo-machine (axial, radial or mixed flow,…)
Used to define performance parameters

23. Matching of a Pump/Fan to A Need
Speed: N (rpm) or n (rps)
This is named as Specific Speed, Ns

24. Popular Definitions for Pumps
The specific speed, usually represented by Ns, also denominated absolute specific speed or specific angular speed.

25. SELECTION OF SPEED
A pump/fan with a given flow geometry and momentum transfer principle

26. Selection of Geometry Vs Specific Speed

27. Speed Vs Size : Constant Head & Flow Rate
Demand Speed nf = 492 rps
N=1000 rpm
N=1500 rpm
N=3000 rpm

29. Performance Parameters
Differential head of pump:

30. Non-dimensional Performance Parameters
, CH = head coefficient
, CQ = flow coefficient
, Re = Reynolds number

31. A similar analysis may be carried out for the power consumption of the pump, P: