Learning Forum

[akndnzmn]

Hello everyone,

I have a system with two air tanks, and a constant flow source providing air at 36 psi pressure. My goal is to calculate how the flow rate from the source will change as I fill the tanks. Initially, Tank 1 has 9 psi and Tank 2 has 16 psi. As air enters the tanks, due to the pressure buildup inside, the flow rate will be directed more towards the tank with the lower pressure, causing fluctuations in the flow rate from the source.

Once the tanks reach the target pressure of 36 psi, the flow to both tanks will stop. I need to determine the following:

1. The time it will take to fill the tanks to 36 psi.
2. How the flow rate will fluctuate during the process due to the pressure differences between the tanks.
3. As the tanks are filled, the lower pressure tank (starting at 9 psi) will eventually catch up to the higher pressure tank (starting at 16 psi). I would like to see the pressure at which the two tanks will equalize, and what is the time it will take for this to happen.

Could someone help me understand how I can model and calculate these flow rate fluctuations and filling times? Also if I assume both tanks are empty initially, how should I set-up my simulation? Should I use multiphase flow and initially set tanks empty?

 

Thanks in advance!

[Rob]

Assuming no phase change you don't need a multiphase model. You will need ideal gas (density changes are going to be important) and to read up on transient models and the patch function.