Pressure change when volume changes for incompressible fluid

Click For Summary

Discussion Overview

The discussion revolves around calculating the pressure increase in a closed tube filled with water when the tube's volume is reduced due to crushing. The context is fluid mechanics, specifically focusing on incompressible fluids and the effects of volume change on pressure.

Discussion Character

  • Homework-related, Technical explanation

Main Points Raised

  • Chris presents a fluid mechanics problem involving a closed tube filled with water, initially pressurized to 10 bar, and seeks to calculate the new pressure after a 10% volume reduction.
  • Chet suggests looking up the bulk compressibility of water, indicating that a 10% decrease in volume may be unlikely.
  • Chris clarifies that the 10% volume reduction is a rough estimate based on the shape of the die used in a hydroforming operation.
  • Chris asks if he can rearrange the equations to solve for the change in pressure (dP) using the provided values.
  • Chet confirms that Chris can rearrange the equations to solve for dP.

Areas of Agreement / Disagreement

There is no consensus on the feasibility of a 10% volume reduction, as Chet expresses skepticism about this figure, while Chris defends it as an approximation based on operational conditions. The discussion remains unresolved regarding the implications of this volume change on pressure calculations.

Contextual Notes

Participants have not fully explored the implications of bulk compressibility in the context of the problem, and there may be assumptions regarding the static nature of the fluid that are not explicitly stated.

Chris F
Messages
2
Reaction score
0

Homework Statement



Hi guys,

My first post here, I hope someone can help me out with a quick fluid mechanics problem.

I'm looking to calculate the pressure increase inside a closed tube full of water when the tube is crushed and therefore its volume reduced.

The tube is filled completely with water and pressurised to a nominal pressure of 10 bar. The starting volume is 2.1l and the volume after crushing is 90% of the initial volume.

2. The relevant equations

The tube remains sealed at all times so I think I can consider the fluid to be static and as its water, incompressible. However I am struggling to find the relevant equation to allow me to calculate the new pressure. All the static problems i have seen are concerned with open containers.

Can anyone help?

Thanks,

Chris
 
Physics news on Phys.org
Look up the BULK COMPRESSIBILITY of water. But a 10% decrease in volume seems very unlikely.

Chet
 
Chestermiller said:
Look up the BULK COMPRESSIBILITY of water. But a 10% decrease in volume seems very unlikely.

Chet

Ok thanks, so i can rearrange to solve for dP using the values i quoted above?

Sorry i should probably explained more thoroughly, I am crushing the tube with a press into a machined die as part of a hydroforming operation, the 10% is a rough approximation using the shape of the die as an indication of the form the tube will take.

Thanks,

Chris
 
Chris F said:
Ok thanks, so i can rearrange to solve for dP using the values i quoted above?Chris
yes.
 

Similar threads

Volume change when cooling a saturated volume of air
  • · Replies 14 ·
Replies
14
Views
3K
How Do Viscous Interactions Differ in Vertical and Horizontal Geometries?
  • · Replies 31 ·
2
Replies
31
Views
4K
Engineering Calculating the mass of air in a pressurised air tank
  • · Replies 14 ·
Replies
14
Views
3K
Measuring the water volume in a small tank with a manometer
  • · Replies 26 ·
Replies
26
Views
2K
Engineering Water Flow from Pressurized Tank through Heat Exchanger
  • · Replies 56 ·
2
Replies
56
Views
6K
Graduate Does Fluid Dynamics Explain Pressure Gradients in a Frictionless Tube?
  • · Replies 48 ·
2
Replies
48
Views
6K
Advanced Hydrodynamic Problem - University level
  • · Replies 49 ·
2
Replies
49
Views
5K
Undergrad What is the pressure of trapped air inside this tube?
  • · Replies 19 ·
Replies
19
Views
1K
Undergrad Internal pressure due to vessel collapse
  • · Replies 4 ·
Replies
4
Views
2K
Pressure resilient linear actuator for subsea applications
  • · Replies 6 ·
Replies
6
Views
4K