Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!

Fan Capacity Diagrams

Pressure, head, air flow volume and fan capacity diagrams.

Pressure head as function of air flow volume may be expressed in a diagram like the one below:

fan capacity diagram

  • red lines are pressure heads as function of air volume flow and speed of the fan
  • green lines marked - l - are throttle lines
  • blue lines are power consumption

Pressure and Head

Operation of fans are often expressed in terms of pressure

pt = ps + pd = constant                                          (1)

where

pt = total pressure (Pa, N/m2)

ps = static pressure (Pa, N/m2)

pd = dynamic pressure (Pa, N/m2)

Dynamic pressure can be expressed as

pd = ρ v2 / 2                                                  (2)

where

ρ = density of air (kg/m3)

v = flow velocity (m/s)

fan pressure head

Head developed can be expressed as

dp = ps2 - ps1 + (v22 - v12) ρ / 2                                                (3)

where

subscription1 is the inlet of the fan and subscription2 is the outlet

3D Engineering ToolBox - draw and model technical applications! 2D Engineering ToolBox - create and share online diagram drawing templates! Engineering ToolBox Apps - mobile online and offline engineering applications!

Unit Converter


















































4.9.9

.