Hot water / cold steam interaction

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SUMMARY

The discussion centers on the thermodynamic interaction between hot water and cold steam in two adiabatic volumes, V1 and V2, connected by a valve. V1 contains high-pressure liquid water at temperature T1, while V2 contains low-pressure steam at temperature T2. Upon opening the valve, the expectation is that liquid water will flash into V2, increasing the pressure in V2 until it equals P1, while the steam condenses and raises T2 above T1, allowing heat diffusion. The discussion highlights the need for a quantitative approach to analyze mass and energy conservation in this scenario.

PREREQUISITES
  • Understanding of adiabatic processes in thermodynamics
  • Knowledge of phase transitions between liquid and gas
  • Familiarity with the principles of heat transfer and pressure equilibrium
  • Basic skills in thermodynamic calculations involving mass and energy
NEXT STEPS
  • Research the principles of adiabatic processes in thermodynamics
  • Study phase change dynamics, particularly condensation and vaporization
  • Learn about pressure-volume relationships in thermodynamic systems
  • Explore the concept of energy conservation in closed systems
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This discussion is beneficial for students and professionals in thermodynamics, engineers working with heat transfer systems, and anyone interested in the behavior of phase changes in adiabatic conditions.

bamse207
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Hello,

I came to consider the following problem, and cannot seem to find the right way to tackle it.
It is not homework, merely a question I'd like to address out of personal curiosity:

Consider two volumes V1 and V2, each assumed adiabatic, and linked with a valve.
V1 is considered infinite (or at least very big compared to V2), V2 being finite and small compared to V1.
V1 is initially filled with, say, water, in liquid state at high pressure (T1, P1). T1 being below the saturation temperature at P1.
V2 is initially filled with steam at lower pressure and temperature (T2 < T1, P2 << P1)
At t=0, the valve is opened, what happens then?
According to the second principle, heat cannot be transferred from the cold steam to the hot water.
However it seems obvious to me that the end state would be liquid, at ~P1 and some other temperature.

Qualitatively, I'm expecting the liquid would flash through the valve from V1 to V2, which would gradually increase P2, until it equals P1. During that process, somehow, the steam in V2 would condense, increasing T2 upto a point where T2 > T1, from which heat can diffuse. Does this sound correct?

Any tips on the right approach to solving this? I've been through a couple of thermodynamics books, and couldn't find any mention of such a situation. Any pointers or keywords to look for to help me find an answer to such a case would be highly appreciated!

thanks!
Laurent
PS: this is my first post here, I hope I've found the right place for it...
 
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I think that you have to give values to V1 and V2 then calculate the total mass and energy in V1 and V2 then combine them and see what temperature water you're left with.
 

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