Tutorial: Fan Simulation in Ventsim™

Fan CurveVentsim™ has a range of powerful facilities to simulate and estimate fan performance in a ventilation model.

Ventsim™ uses a database of fan curves and settings to estimate the performance of fans in in any application underground. To ensure fans are accurately simulated, at a minimum, pressure and quantity fan curve information must be entered into the fan table (available from the Tools > Fans menu item).

To get the most out of fan simulation however, consider entering the additional optional information for more accurate results.

  • image015Fan diameter or discharge area – Ventsim™ uses discharge size to calculate the velocity of air discharging from a fan. When using total pressure simulation, if the fan is located underground, then Ventsim™ assumes both fan static and velocity pressure (total pressure) is used to drive the airflow ventilation through the mine. If the fan is exhausting to the surface, Ventsim™ assumes the fan velocity pressure discharge is wasted to the surface atmosphere and is not used for underground ventilation.
  • Fan Curve Density is an important parameter which Ventsim™ uses to modify fan performance at different air densities. The density in the Fan Database must be entered according to the manufactures fan curve specification NOT at the air density of the mine to be simulated. When the fan is placed in the mine ventilation simulation, Ventsim™ will automatically modify the fan curve to suit the simulated density.)
  • Include efficiency or power curves in the fan database tables. Ventsim™ uses this information to accurately calculate power consumption and cost of ventilation. The information is also used to calculate heat from fans during heat simulations. Only efficiency or power data needs to be entered (not both) as Ventsim™ automatically calculated the other data. If the information is not available, Ventsim™ uses a default efficiency (set in the Settings, which may not be as accurate.
  • Only Fan Static or Total Pressure need be entered (not both). It is recommended to use Fan Total Pressure where possible. Fan Total Pressure allows Ventsim™ to use the discharge velocity pressure to help estimate fan performance underground. If this is ignored and only fan static pressure used, fans may underperform in the simulation compared to real life.

Applying Fans in Ventsim™

image016When placing a fan in a ventilation model, use the EDIT command to specify the fan configuration. Note that options are also available to adjust the fan speed (a facility available on many new variable speed fans) for increasing or decreasing performance. Pressing SIMULATE will update the simulation and show fan performance and duty points.

When assessing fan performance, ensure that the operating point of the fan does not exceed the maximum (stall) pressure. Fan performance and airflow in real terms will dramatically decrease, and fan life may be decreased. Try to design ventilation simulations well below this stall point to allow for some contingency in real life fan pressures.

Also ensure fans are not operated below the minimum (low or negated) specified fan curve pressure. While fans in real terms will still operate, power efficiency is likely to be poor, and some fan designs produce excessive vibration or blade stress. Choose a fan more suitable for this pressure duty if possible.