Airflow rate through a rectangular section

[stoky]

I need to mount several rectangular orifices or sections on a wall with those two factors:

- 20 Pascals differential pressure (negative pressure inside)
- Inlet air speed 1100 feet per minute (5.58 meters per minute)

I've got the section of each window, and the air caudal to renovate. I would like to know how much sections (separated each other) I need. How could I calculate that?

 

[gtoguy97]

The first step to calculating the number of sections is to determine the total area required for all the orifices. This can be done by dividing the total air flow (or caudal) by the inlet air speed. For example, if the total air flow is 50 cubic meters per minute and the inlet air speed is 5.58 meters per minute, then the total area required for all the orifices would be 8.9 square meters.Once you have determined the total area required, you can calculate the number of orifice sections you need by dividing the total area by the area of each individual orifice section. For example, if you have an orifice section with a width of 1 meter and a height of 2 meters, then the total area of the orifice section would be 2 square meters. Therefore, if you need a total area of 8.9 square meters, you will need 4.45 orifice sections (8.9/2 = 4.45).Finally, you should also consider the 20 pascals differential pressure when calculating the number of orifice sections. As the differential pressure increases, the size of the orifice sections must also increase in order to maintain the same air flow rate. Therefore, you may need to adjust the number of orifice sections depending on the differential pressure.