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Heating water at constant volume and pressure

  • Thread starter debussie
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  • #1
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A rigid tank has a volume of 0.01m3. It initially contains saturated water at a temperature of 200°C and a quality of 0.4. The top of the tank contains a pressure-regulating valve that maintains the vapor at constant pressure. This system undergoes a process whereby it is heated until all the liquid vaporizes. How much head (in kJ) is required? You may assume that there is no pressure drop in the exit line.
 

Answers and Replies

  • #2
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Please could you provide your attempt at the solution.

Jared
 
  • #3
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So far I have used the quality given, and the steam tables to calculate the total molar volume and total mass of the water:

Vm=(1-x)Vml+xVmv
m=V/Vm

I am assuming that the temperature of the system wont change because vapor will continue to leave as more vapor is created. I'm not sure where to go from here. Does Q=change in U? How do I keep track of the energy that is leaving with the vapor?
 
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