Airflow in pipes/tubes

[Maso]

Hi, Is there anyone out there who can help me with the following request.
I am looking for a simplified equation to determine the approximate flow rate of air in a pipe/tube, given the upstream pressure and inside diameter.???

 

[Shmulik]

You my look at the following:

http://www.cleandryair.com/pressure_loss.htm

http://pump.net/otherdata/airflowsched40.htm

 

[hacksaw]

for lack of other details, just assume a nominal velocity and estimate it.