Free Jet Pressure: Atmospheric or Boiling?

In summary, the conversation discusses a tank with a small nozzle where water falls down as a free jet. The pressure within the jet is equal to atmospheric pressure at any point, according to books. However, this contradicts the fact that water should boil when its absolute pressure is equal to atmospheric pressure. The conversation then asks for an explanation and clarifies that the water at room temperature and atmospheric pressure does not boil. The answer is that when the vapor pressure of the water is equal to atmospheric pressure, it will boil.
  • #1
R Power
271
0
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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  • #2
anyone please help!
 
  • #3
Hye, come on someone please help!
 
  • #4
Why should the water boil? Water at room temperature and atmospheric pressure doesn't boil.
 
  • #5
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
 
  • #6
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
 

1. What is a free jet and how does it relate to pressure?

A free jet is a flow of fluid that is not confined by any boundaries or surfaces. It is considered to be in a state of atmospheric pressure, meaning the pressure is equal to the surrounding atmosphere. In the case of a boiling free jet, the pressure is influenced by the phase change of the fluid from liquid to gas.

2. How does the pressure in a free jet change with distance from the source?

The pressure in a free jet decreases as the distance from the source increases. This is due to the fluid expanding and spreading out as it moves away from the source. In a boiling free jet, the pressure may also decrease due to the phase change of the fluid.

3. What factors affect the pressure in a free jet?

The pressure in a free jet is affected by factors such as the velocity of the jet, the density and viscosity of the fluid, and the presence of any obstacles or boundaries in its path. In a boiling free jet, the pressure may also be influenced by the temperature and the phase change of the fluid.

4. How does the pressure in a free jet differ from that of a confined jet?

In a free jet, the pressure is equal to the surrounding atmosphere and decreases with distance from the source. In a confined jet, the pressure is higher and remains constant until it reaches a boundary or obstacle, where it will increase or decrease depending on the type of jet.

5. Why is understanding free jet pressure important in scientific research?

Understanding free jet pressure is important in various fields of science, such as fluid mechanics, aerodynamics, and chemical engineering. It allows for the accurate prediction and control of fluid flows, which is crucial in designing efficient and safe systems and processes.

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