Thrust of an underpressure tank of air

[Raresss]

How can I calculate the thrust of an underpressure tank of air when the valve is released? If you can, please, explain in detail. Thank you!

 

[Bystander]

"Underpressure?" Less than ambient?

 

[Raresss]

"Underpressure?" Less than ambient?

More than the ambient pressure

 

[sophiecentaur]

More than the ambient pressure

Pressure "under" what? Do you mean when it's running out?

 

[CWatters]

The OP just means the thrust produced by air escaping from a cylinder of compressed air.

Most people in my country understand "under" to mean "due to". As in "The bridge failed under the weight of traffic".

 

[CWatters]

If you can measure the mass flow rate and velocity of the air escaping see "net thrust"...

https://en.m.wikipedia.org/wiki/Rocket_engine#Net_thrust

 

[sophiecentaur]

The OP just means the thrust produced by air escaping from a cylinder of compressed air.

Most people in my country understand "under" to mean "due to". As in "The bridge failed under the weight of traffic".

I can see that now. In English, underpressure and "underweight" (compound words) have different meanings from when the two words are separated by a space; hence my confusion. If this were a German forum, things might be different. . .

 

[Raresss]

Can the mass flow rate and the velocity of the exhausted gas be calculated or those can only be measured in an experiment ?

 

[DrStupid]

Can the mass flow rate and the velocity of the exhausted gas be calculated or those can only be measured in an experiment ?

Bernoulli should be a good approximation.

If this were a German forum, things might be different. . .

Not really. "Unterdruck" instead of "unter Druck" would result in the same confusion.

 

[mrspeedybob]

Would it not just be the pressure in the tank x the area of the orifice?
I.E. If the pressure is 1 Mpa (above ambient) and the orifice is 1²mm then the thrust should be 1 Newton, right?

 

[Raresss]

Would it not just be the pressure in the tank x the area of the orifice?
I.E. If the pressure is 1 Mpa (above ambient) and the orifice is 1²mm then the thrust should be 1 Newton, right?

Your force is the normal force, and your pressure is the surface pressure. We can't use those in my problem. The thrust is based on other variables . Check out this link to find out more : https://en.wikipedia.org/wiki/Thrust