1. H. Clay Moore & Associates Key Account Manager - Nuclear
Fan & Systems
Chris Carr PE
H. Clay Moore & Associates
Rod Furniss
Howden North America
Key Account Manager - Nuclear

2. 3 Aerodynamics • Pressure & Flow Definitions and Measurement
• Development of Fan Curves
• Performance of Various Blade Shapes
• Fan Controls
System Effects

3. HNA Profile

4. Aerodynamics What is a Fan?
Any device for producing a current of air by the movement of a broad surface or a number of such surfaces. 4

5. Aerodynamics Fan Flow Rate Often called inlet volume
Pressure & Flow Definitions and Measurement
Fan Flow Rate
Often called inlet volume
Measured at the fan inlet, by convention
Measured in cubic feet per minute (cfm)
May be converted to scfm (standard cubic feet per minute), or mass flow (lb/hr)
Fan manufacturers commonly use acfm (actual cubic feet per minute) 5

6. Aerodynamics Pressure Absolute Pressure Barometric Pressure
Pressure & Flow Definitions and Measurement
Pressure
Force per Unit Area
Commonly measured in psi or inwg
Absolute Pressure
Pressure when the datum is absolute zero
iiAlways positive
Barometric Pressure
Absolute pressure exerted by the atmosphere
Always positive
Gauge Pressure
Pressure when the datum is barometric pressure
May be positive or negative 6

7. Aerodynamics Static Pressure Velocity Pressure Total Pressure
Pressure & Flow Definitions and Measurement
Static Pressure
Pressure due to degree of compression and density only
May be positive or negative
Velocity Pressure
Pressure due to rate of motion and density only
Always positive
Total Pressure
Algebraic sum of static and velocity pressures at a point 7

8. Aerodynamics Fan Total Pressure Fan Velocity Pressure
Pressure & Flow Definitions and Measurement
Fan Total Pressure
Difference in Total Pressure between the fan outlet and fan inlet
FTP = TPo - TPi
Fan Velocity Pressure
Pressure corresponding to the average velocity at the fan outlet
FVP = VPo
Fan Static Pressure
Fan Total Pressure minus Fan Velocity Pressure
FSP = SPo – TPi
Static Pressure Rise
Difference in Static Pressure between the fan outlet and fan inlet
SPR = SPo - SPi 8

9. Aerodynamics Image area Fan Pressure Terms
Pressure & Flow Definitions and Measurement
Fan Pressure Terms
For a Given Fan, SPR is iiiAlways Greater Than FSP
If the Specified Pressure is iiiAssumed to Be FSP, the Fan iiiSelected Will Be Smaller
Image area 9

10. Aerodynamics Image area Pitot – Static Tube
Pressure & Flow Definitions and Measurement
Pitot – Static Tube
Image area 10

11. Aerodynamics Image area Fan Laboratory Test Setup
Pressure & Flow Definitions and Measurement
Fan Laboratory Test Setup
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12. Aerodynamics
Development of Fan Curves
Fan Curve
Image area 12

13. Aerodynamics
Development of Fan Curves
System Curve
Image area 13

14. Aerodynamics Image area P-V and Peak Fan Pressure
Development of Fan Curves
P-V and Peak Fan Pressure
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15. Aerodynamics
Development of Fan Curves
Selection Range
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16. Aerodynamics Common Blade Shapes Airfoil
Performance of Various Blade Shapes
Common Blade Shapes
Airfoil
Backward Curved / Backward Inclined
Radial / Radial Tip
Forward Curved
Axial 16

17. Aerodynamics Image area Airfoil Highest Efficiency Centrifugal DDesign
Performance of Various Blade Shapes
Airfoil
Highest Efficiency Centrifugal DDesign
Limit Load HP Characteristic
Low Noise
Usually for Clean Applications
Largest Diameter Centrifugal
Highest Cost Centrifugal
Image area 17

18. Aerodynamics Image area Backward Curved / Backward Inclined
Performance of Various Blade Shapes
Backward Curved / Backward Inclined
Essentially a Single TThickness Airfoil
Efficiency slightly less than AAirfoil
Limit Load HP Characteristic
Low Noise
For Clean or Dirty AApplications
Lower Cost than Airfoil
Image area 18

19. Aerodynamics Image area Radial / Radial Tip Lower Efficiency
Performance of Various Blade Shapes
Radial / Radial Tip
Lower Efficiency
Continuously Rising HP .. CCharacteristic
Higher Noise Levels
May have Predominant BFP TTone
Smaller Diameter
Easily Armored for Erosive SService
Lower Cost
Image area 19

20. Aerodynamics Image area Forward Curved (SiroccoTM) Lower Efficiency
Performance of Various Blade Shapes
Forward Curved (SiroccoTM)
Lower Efficiency
Continuously Rising HP CCharacteristic
Smallest Diameter Centrifugal
Suited for High Volume/Low PPressure
Distinctive Dip in P-V Curve
Seldom Used Today
Image area 20

21. Aerodynamics Image area Axial Airflow Parallel to Axis of RRotation
Performance of Various Blade Shapes
Axial
Airflow Parallel to Axis of RRotation
High Efficiency
Limit Load HP Characteristic
Low Noise
Suited for High Volume/Low PPressure
Adjustable or Controllable Pitch
Distinctive Dip in P-V Curve
Controllable Pitch has Higher CCost
Image area 21

22. Aerodynamics Fan Control Reasons for Providing Fan Control
Fan Controls
Fan Control
Reasons for Providing Fan Control
Methods of Control
Efficiency Comparison
Mechanical Arrangements
Control Criteria 22

23. Aerodynamics Reasons for Providing Fan Control
Fan Controls
Reasons for Providing Fan Control
Uncertainty in System Calculations
Safety Factor or Margin
Expected Changes in the System with Time
Normal Process Variations
Provisions for Extraordinary Events 23

24. Aerodynamics Image area System Pressure Loss and Fan Design Pressure
Fan Controls
System Pressure Loss and Fan Design Pressure
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25. Aerodynamics
Fan Controls
Moving the Operating Point
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26. Aerodynamics
Fan Controls
System Duty Cycle
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27. Aerodynamics Methods of Control None Outlet / System Damper
Fan Controls
Methods of Control
None
Outlet / System Damper
Inlet Box Dampers
Variable Inlet Vanes (VIV)
Variable Speed
Blade Pitch Control
Combinations of the Above 27

28. Aerodynamics
Fan Controls
Outlet Damper / System Damper
Image area 28

29. Aerodynamics
Discharge Damper

30. Aerodynamics
Fan Controls
Inlet Box Dampers
Image area 30

31. Aerodynamics
Fan Controls
Inlet Box Dampers
Image area 31

32. Aerodynamics
Fan Controls
Inlet Box Dampers
Image area 32

34. IBD
Discharge

35. IBD
Discharge

36. Aerodynamics
Fan Controls
Variable Inlet Vanes
Image area 36

37. Aerodynamics Image area Physical Arrangement of Cantilevered VIV
Fan Controls
Physical Arrangement of Cantilevered VIV
Image area 37

38. Aerodynamics Image area Physical Arrangement of Radial Vane Control
Fan Controls
Physical Arrangement of Radial Vane Control
Image area 38

39. Aerodynamics
Fan Controls
VIV Fabrication
Image area 39

40. Aerodynamics
Fan Controls
Variable Inlet Vanes
Image area 40

41. Aerodynamics
Fan Controls
Variable Speed
Image area 41

42. Aerodynamics Variable Speed- VFD and Gỳrol Fluid Drive Rotating Stall
Fan Controls
Variable Speed- VFD and Gỳrol Fluid Drive
Rotating
Stall

43. Aerodynamics
Fan Controls
Blade Pitch Control
Image area 43

44. Aerodynamics
Fan Controls
Efficiency Comparison
Image area 44

45. Aerodynamics Image area
Fan Controls
Physical Arrangement of Various Control Devices
Image area 45

46. Aerodynamics Image area
Fan Controls
Physical Arrangement of Axial Blade Pitch Control
Image area 46

47. Aerodynamics Control Criteria Turndown / Leakage
Fan Controls
Control Criteria
Turndown / Leakage
Sensitivity to Change / Stability / Transients
Accuracy Required
Repeatability
Expected Efficiency
Acoustic Considerations
Structural Considerations 47

48. System Effects – Poor Flow48

49. System Effects – Poor Flow49

50. System Effects – Poor Flow50

51. System Effects – Poor Flow51

52. H. Clay Moore & Associates Key Account Manager - Nuclear
Fan & Systems
Chris Carr PE
H. Clay Moore & Associates
Rod Furniss
Howden North America
Key Account Manager - Nuclear