Jump to content

Force exerted by pressure...


Externet

Recommended Posts

Greetings.

A hose/pipe/tube is friction push-inserted into a vessel tight hole.   Transport yourself to the interior of the pressurized vessel.  You can see the inserted pipe end that supplies the pressurized -say air-.

3" x 21 ft Schedule 40 Black Steel Plain End Pipe | Fastenal

There is in-diameter and out-diameter, corresponding to inside area; outside area, and the smaller torus area from the pipe wall.

What is the force the air pressure in the vessel pushes the pipe out towards unplugging it ? ---> force = pressure / area

Which is the area to consider ?  inside, outside, torus ?

Link to comment
Share on other sites

On 11/10/2022 at 7:16 PM, sethoflagos said:

The force acting to propel the pipe back out of the hole in the vessel is equal to absolute fluid pressure times the area of the hole in the vessel. 

To do justice to your question, @Externet I should add that strictly speaking my response corresponds to the 'design load' on the nozzle when there is either no flow (due to eg a closed valve), or when the fluid is sufficiently viscous that its shearing force on the pipe wall far exceeds its gain in momentum. 

At the other end of the spectrum, we could in theory propose the unrestricted flow of a zero viscosity fluid where none of the fluid inertial acceleration is lost to shear at the pipe wall. In this case, the only axial force acting on the pipe in opposition to the restraining force of the interference fit, would be the vessel pressure acting on the pipe thickness (your 'torus' case). 

Real flowing cases should be expected to fall somewhere between these limits. 

In short, good question. Deserved a more considered answer.

Edited by sethoflagos
small clarification
Link to comment
Share on other sites

  • 2 months later...

Pressure equals force divided by area (P=FA P = F A ). The equation shows that pressure is directly proportional to force, but inversely proportional to area. At a constant area, pressure increases as the magnitude of the force applied also increases.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.