Free Jet Pressure: Atmospheric or Boiling?

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Discussion Overview

The discussion revolves around the pressure within a free jet of water exiting a nozzle into the atmosphere. Participants explore the implications of pressure being equal to atmospheric pressure and whether this condition leads to boiling of the water.

Discussion Character

  • Exploratory
  • Debate/contested

Main Points Raised

  • One participant asserts that the pressure within the free jet at any point should be atmospheric pressure, based on the idea that pressure at the nozzle exit is atmospheric.
  • Another participant questions why the water should boil if the pressure is atmospheric, noting that water at room temperature does not boil under these conditions.
  • A different viewpoint clarifies that boiling occurs when the vapor pressure equals atmospheric pressure, suggesting a distinction between absolute pressure and vapor pressure.
  • There is a reiteration of the idea that boiling is related to vapor pressure rather than just absolute pressure being equal to atmospheric pressure.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between pressure and boiling, with no consensus reached on the implications of atmospheric pressure in the context of the free jet.

Contextual Notes

Participants have not fully resolved the definitions of pressure types (absolute vs. vapor pressure) and their implications for boiling in the context of the free jet scenario.

R Power
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Hi friends
Consider a tank with a small nozzle at the bottom open to atmosphere. Water falls down through the nozzle as free jet as in figure attached . According to books pressure within this free jet at any point say point 1 will be equal to atmospheric pressure. This is because pressure at point 2 will be atmospheric and so at any cross sectional plane X-X pressure will be same, so at point 1 pressure will be atmospheric. Similarly, at any point within this free jet pressure will be atmospheric.
But if absolute pressure within free jet is atmospheric then the water should boil. Can u explain this.
 

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anyone please help!
 
Hye, come on someone please help!
 
Why should the water boil? Water at room temperature and atmospheric pressure doesn't boil.
 
Why should the water boil? Water at room temperature and atmospheric pressure doesn't boil.
But when absolute pressure of water (i.e pressure within water) becomes equal to atmospheric pressure, it boils
 
R Power said:
But when absolute pressure of water (i.e pressure within water) becomes equal to atmospheric pressure, it boils

No, when the vapor pressure is equal to atmospheric pressure it will boil.

CS
 

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