# Calculating airflow with pressure and diameter?

Hi.

Is there any way to calculate airflow out of a tube (into atmosphere) with only the pressure and cross sectional area of the tube?

## Answers and Replies

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Chestermiller
Mentor
Hi.

Is there any way to calculate airflow out of a tube (into atmosphere) with only the pressure and cross sectional area of the tube?
Are you talking about the upstream pressure? If so, you also need to know the length of the tube and the temperature (which determines the density and viscosity).

Are you talking about the upstream pressure? If so, you also need to know the length of the tube and the temperature (which determines the density and viscosity).
Downstream.. Exit to atmosphere

BvU
Science Advisor
Homework Helper
2019 Award
Google is your friend (4.1)
'only the pressure' is weird if you mention 'tube' (link is for 'opening' , i.e. tube of length 0 )

Drat, slow typing again ..

Chestermiller
Mentor
Downstream.. Exit to atmosphere
Then the answer to your original question is "no"

enanthate
CWatters
Science Advisor
Homework Helper
Gold Member
Hi.

Is there any way to calculate airflow out of a tube (into atmosphere) with only the pressure and cross sectional area of the tube?
Companies that make spray nozzles have calculators that will give you the flow rate given the pressure in the pipe leading to the nozzle (eg the upstream pressure) but they assume they are spraying into air (eg downstream pressure is 1 atmosphere).