Air flow between two different pressures

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SUMMARY

The discussion focuses on calculating the hole diameter required to deflate a chamber with a pressure difference of 120 mm Hg within 5 minutes. The user intends to apply Bernoulli's equation to convert static pressure into dynamic pressure and determine the air velocity. Given a starting volume of 0.10508 in³, the required flow rate is calculated to be approximately 3.502666 x 10^-4 in³/s. The user seeks clarification on the application of Bernoulli's equation to derive the necessary hole diameter for this specific scenario.

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  • Knowledge of fluid dynamics principles
  • Familiarity with pressure measurement units (mm Hg, atmospheric pressure)
  • Basic calculations involving volume, flow rate, and area
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  • Study Bernoulli's equation in detail to understand its derivation and applications
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  • Explore methods for calculating hole diameter based on flow rate and pressure differentials
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Engineers, physicists, and students involved in fluid dynamics, particularly those working on pressure-related projects or applications requiring precise calculations for airflow and deflation processes.

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I have a problem for a project I'm doing:
I have one chamber that is 120 mm Hg higher than another chamber(which is at atmospheric pressure) and is slowly being deflated. Force being applied causes this 120 pressure difference, and is constantly being applied. The 2nd chamber will always be atmospheric, as the added air will not make a difference. I have a starting volume of the higher pressure chamber, but as the chamber is deflating, the volume will change. I want the volume to completely deflate in 5 min, and i will be solving for the diameter hole i need for this to happen. The volume is small, and the hole will be extremely small. How would I do this? Thank you for the help
 
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Assuming no other losses, apply Bernoulli's equation to all of that static pressure difference to dynamic pressure and calculate the associated velocity of the air. Then its just volume divided by flow rate divided by velocity to get area.
 
So if you have a volume of .10508 in^3 that you want to deflate in 300 s, that is 3.502666 X 10^-4 in^3/s for a flow rate. The pressure difference starts at 120 mm Hg, the air density is about 1.2 kg/m^3. What would you get for the hole diameter? or what exactly will the equation look like, i am not very familiar with Bernoulli's equation. I just want to make sure I do this right, thanks a lot.
 
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