VFreshEngineer
Mechanical
- Jan 7, 2022
- 14
Hello,
I try to calculate pressure drop through rectangular ducting (sound baffle), which will be placed on air inlet. I'm new to this and need some guidance.
Screenshot for reference:
I found formula for calculatig equivalent hydralic diameter for rectangular shaped duct on Engineering toolbox - Link
Since the duct has 4 openings, I only considered flow through one opening to simplify. I devided required air volume flow (2 m3/s) by 4 and used Engineering Toolbox excel template
According to the template I've got head loss of 1316 Pa/100m. To calculate the total head loss through duct channel I've used following equation:
Pdiff = 1316/100 * Length of duct channel * Number of openings
I've got head loss that equals to 26 Pa. Seems a bit low, but it's a half meter duct ... so it seems realistic.
I'm tottally green in this field and will appriciate all the support I can get.
General inputs
Opening's height: 800 mm
Opening's width: 62,5 mm
Length of duct channel: 0,5 m
Number of openings: 4
Required min. air flow: 2 m3/s
Attaching Excel spreadsheet for reference.
I try to calculate pressure drop through rectangular ducting (sound baffle), which will be placed on air inlet. I'm new to this and need some guidance.
Screenshot for reference:

I found formula for calculatig equivalent hydralic diameter for rectangular shaped duct on Engineering toolbox - Link
Since the duct has 4 openings, I only considered flow through one opening to simplify. I devided required air volume flow (2 m3/s) by 4 and used Engineering Toolbox excel template
According to the template I've got head loss of 1316 Pa/100m. To calculate the total head loss through duct channel I've used following equation:
Pdiff = 1316/100 * Length of duct channel * Number of openings
I've got head loss that equals to 26 Pa. Seems a bit low, but it's a half meter duct ... so it seems realistic.
I'm tottally green in this field and will appriciate all the support I can get.
General inputs
Opening's height: 800 mm
Opening's width: 62,5 mm
Length of duct channel: 0,5 m
Number of openings: 4
Required min. air flow: 2 m3/s
Attaching Excel spreadsheet for reference.