01 - Ashrae - Aerodynamics

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01 - Ashrae - Aerodynamics...

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Fan & Systems Chris Carr PE H. Clay Moore & Associates Rod Furniss Howden North America Key Account Manaer ! Nuclear 

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 Aerodynamics # Pressure & Flow $e%initions and Measurement # $eelo'ment o% Fan Cures # Per%ormance o% (arious )lade Sha'es # Fan Controls • System E%%ects

HNA Pro%ile

Aerodynamics

,hat is a Fan•

 Any device for producing a current of air by the movement of a broad surface or a number of such surfaces.

Aerodynamics Pressure & Flow $e%initions 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)



 an manufacturers commonly use acfm (actual cubic feet per minute)

Aerodynamics Pressure & Flow $e%initions and Measurement

Pressure •

  orce per !nit Area



  "ommonly measured in psi or inwg

A0solute Pressure • •

#ressure when the datum is absolute $ero ii Always positive

)arometric Pressure • •

 Absolute pressure e%erted by the atmosphere Always positive

aue Pressure • •

#ressure when the datum is barometric pressure May be positive or negative

Aerodynamics Pressure & Flow $e%initions and Measurement

Static Pressure •



#ressure due to degree of compression and density only May be positive or negative

(elocity Pressure • •

#ressure due to rate of motion and density only Always positive

3otal Pressure • •

 Algebraic sum of static and velocity pressures at a point May be positive or negative

Aerodynamics Pressure & Flow $e%initions and Measurement

Fan 3otal Pressure • •

  &ifference in 'otal #ressure between the fan outlet and fan inlet   '#  '#o  '#i

Fan (elocity Pressure •



 #ressure corresponding to the average velocity at the fan outlet   *#  *#o

Fan Static Pressure •



  an 'otal #ressure minus an *elocity #ressure   +#  +#o  '#i

Static Pressure Rise •



 &ifference in +tatic #ressure between the fan outlet and fan inlet   +#-  +#o  +#i

Aerodynamics Pressure & Flow $e%initions and Measurement

Fan Pressure 3erms •



6mae area

or a iven an, +#- is iii Always reater 'han +# f the +pecified #ressure is iii Assumed to 0e +#, the an iii+elected 1ill 0e +maller 

Aerodynamics Pressure & Flow $e%initions and Measurement

Pitot 8 Static 3u0e

6mae area

Aerodynamics Pressure & Flow $e%initions and Measurement

Fan 9a0oratory 3est Setu'

6mae area

Aerodynamics $eelo'ment o% Fan Cures

Fan Cure

6mae area

Aerodynamics $eelo'ment o% Fan Cures

System Cure

6mae area

Aerodynamics $eelo'ment o% Fan Cures

P!( and Pea: Fan Pressure

6mae area

Aerodynamics $eelo'ment o% Fan Cures

Selection Rane

6mae area

Aerodynamics Per%ormance o% (arious )lade Sha'es

Common )lade Sha'es •

  Airfoil



 0ac2ward "urved / 0ac2ward nclined



  -adial / -adial 'ip



 orward "urved



  A%ial

Aerodynamics Per%ormance o% (arious )lade Sha'es

Air%oil •

6mae area

3ighest 4fficiency "entrifugal &&esign



 5imit 5oad 3# "haracteristic



  5ow 6oise



  !sually for "lean  Applications



 5argest &iameter "entrifugal



 3ighest "ost "entrifugal

Aerodynamics Per%ormance o% (arious )lade Sha'es

)ac:ward Cured ; )ac:ward 6nclined •



6mae area

4ssentially a +ingle ''hic2ness Airfoil 4fficiency slightly less than  A Airfoil



5imit 5oad 3# "haracteristic



5ow 6oise





or "lean or &irty  A Applications 5ower "ost than Airfoil

Aerodynamics Per%ormance o% (arious )lade Sha'es

Radial ; Radial 3i' •





6mae area •







5ower 4fficiency "ontinuously -ising 3# .. ""haracteristic 3igher 6oise 5evels May have #redominant 0# ''one +maller &iameter  4asily Armored for 4rosive ++ervice 5ower "ost

Aerodynamics Per%ormance o% (arious )lade Sha'es

Forward Cured $am'ers

6mae area

Aerodynamics Fan Controls

6nlet )o> $am'ers

6mae area

0&

&ischarge

0&

&ischarge

Aerodynamics Fan Controls

(aria0le 6nlet (anes

6mae area

Aerodynamics Fan Controls

Physical Arranement o% Cantileered (6(

6mae area

Aerodynamics Fan Controls

Physical Arranement o% Radial (ane Control

6mae area

Aerodynamics Fan Controls

(6( Fa0rication

6mae area

Aerodynamics Fan Controls

(aria0le 6nlet (anes

6mae area

Aerodynamics Fan Controls

(aria0le S'eed

6mae area

Aerodynamics Fan Controls

(aria0le S'eed! (F$ and @rol Fluid $rie Rotatin Stall

Aerodynamics Fan Controls

)lade Pitch Control

6mae area

Aerodynamics Fan Controls

E%%iciency Com'arison

6mae area

Aerodynamics Fan Controls

Physical Arranement o% (arious Control $eices

6mae area

Aerodynamics Fan Controls

Physical Arranement o% A>ial )lade Pitch Control

6mae area

Aerodynamics Fan Controls

Control Criteria •

  'urndown / 5ea2age



 +ensitivity to "hange / +tability / 'ransients



  Accuracy -e8uired



  -epeatability



  4%pected 4fficiency



  Acoustic "onsiderations



  +tructural "onsiderations

System E%%ects 8 Poor Flow

System E%%ects 8 Poor Flow

System E%%ects 8 Poor Flow

System E%%ects 8 Poor Flow

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