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In a pressure cooker, increasing static pressure causes evaporation of water to be less thermodynamically favorable, and increases the rate of condensation of water. This is because water molecules have to overcome a greater pressure to escape the body of liquid water.

The first part of my question is, do I have all that right?

The second part is, assuming I do have that right, is the same true for dynamic pressure or does only static pressure influence evaporation and condensation?

Charlie Boardman
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  • What is dynamic pressure? – David White Aug 13 '21 at 18:58
  • @David https://en.wikipedia.org/wiki/Dynamic_pressure

    "It can be thought of as the fluid's kinetic energy per unit volume. "

    It's dimensionally equivalent to static pressure and gets used in engineering. You can also think of it as the pressure that would be produced by a flowing fluid once it stagnates against a surface.

     – Charlie Boardman Aug 13 '21 at 19:01
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    I read a bit of the link, and noticed this partial statement in the first sentence: "In incompressible fluid dynamics". Steam is compressible. – David White Aug 13 '21 at 19:03
  • Yes. At the same time, air at slow enough speeds does approximately follow the Bernoulli equation and you can talk meaningfully about dynamic pressure. See the picture and caption from the link: https://en.wikipedia.org/wiki/Dynamic_pressure#/media/File:VenturiFlow.png – Charlie Boardman Aug 13 '21 at 19:08
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    "In a pressure cooker, increasing static pressure causes evaporation of water to be less thermodynamically favorable...do I have all that right?" You do not have this part right. Increasing the pressure on condensed matter very slightly increases the equilibrium vapor pressure. – Chemomechanics Aug 13 '21 at 20:39
  • I suspect that there is something that you have in mind, but I can't tell what it is. Can you be more specific in your question? – David White Aug 13 '21 at 23:29

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