Natural inlet shaft modelling

[RaulBigMagicSpirit]

Hello all,

I use the HVAC model to simulate natural shafts. I include two nodes (in yellow) which represent the damper and the air contractions in the inlet. The k factor for the damper is provided by the manufacturer. Both nodes are linked with a duct, the pressure drop along the duct depends on lenght, area, perimeter and roughness. No minor losses are considered.

However, by considering the real natual shaft (in the left), the incoming air spins 90 degree to enter the damper (area in purple circle). How could I consider the pressure drop of this spin in the model? or is it already in someway included in the duct?

Thanks

[rmcdermo]

Add another node with K factor for a 90 degree elbow.

[drjfloyd]

You don't need a second node. See section 10.2.1 in the Guide and in particular Fig 10.5 and Eq. 10.3.

[RaulBigMagicSpirit]

Thanks! Checking on it