Free Jet Pressure: Atmospheric or Boiling?

  • Thread starter Thread starter R Power
  • Start date Start date
  • Tags Tags
    Jets Pressure
Click For Summary
The discussion centers on the pressure dynamics of a free jet of water exiting a nozzle into the atmosphere. It is asserted that the pressure within the free jet at any point remains equal to atmospheric pressure, leading to confusion about whether the water should boil. Clarification is provided that water at room temperature and atmospheric pressure does not boil, as boiling occurs only when the vapor pressure equals atmospheric pressure. The key point is that while the absolute pressure within the jet is atmospheric, it does not lead to boiling unless the vapor pressure reaches that level. The conversation emphasizes the distinction between absolute pressure and vapor pressure in understanding boiling conditions.
R Power
Messages
270
Reaction score
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.
 

Attachments

  • Untitled.jpg
    Untitled.jpg
    6.3 KB · Views: 755
Physics news on Phys.org
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
 

Thread 'Mousetrap Car Energy efficiency'

For simple comparison, I think the same thought process can be followed as a block slides down a hill, - for block down hill, simple starting PE of mgh to final max KE 0.5mv^2 - comparing PE1 to max KE2 would result in finding the work friction did through the process. efficiency is just 100*KE2/PE1. If a mousetrap car travels along a flat surface, a starting PE of 0.5 k th^2 can be measured and maximum velocity of the car can also be measured. If energy efficiency is defined by...
View full post »

Similar threads

Pressure variation across streamlines in a free jet
  • · Replies 25 ·
Replies
25
Views
7K
Undergrad Understanding the thrust generated by a typical jet engine
  • · Replies 2 ·
Replies
2
Views
3K
Undergrad Find Best Water Nozzle Type & Pressure for Longest Distance
  • · Replies 32 ·
2
Replies
32
Views
10K
Water pressure affects air pressure
  • · Replies 9 ·
Replies
9
Views
3K
Undergrad Free fall of person in a sled to direct horizontal motion by atmospheric resistance
  • · Replies 12 ·
Replies
12
Views
565
Calculate Pressure & Speed of Submerged Water Jet 100mm Away
  • · Replies 3 ·
Replies
3
Views
3K
Estimating the force exerted by a water jet on a flat plate - Bernoulli vs Momentum Equation
  • · Replies 11 ·
Replies
11
Views
3K
Explaining Pressure & Depth Relationships in Fluids Using Halliday & Resnick
  • · Replies 4 ·
Replies
4
Views
2K
Boiling point Atmospheric/hydrostatic pressure
  • · Replies 6 ·
Replies
6
Views
3K
What is the approximate pressure at the center of a cool Earth with no gravity?
  • · Replies 1 ·
Replies
1
Views
2K