01 - Ashrae - Aerodynamics

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

*

 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