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# Mixing steam and water

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 The problem I need to solve is I have steam at a fixed volume of .00522716 ft^3, a pressure of 10.504 lbf/in^2, and a mass of .000212lb if I spray in water at 68 degrees Fahrenheit with a mass of .001lb what is my final pressure and temperature? If someone could show me how to calculate this it would be greatly appreciated. Thanks Adam
 zdas04 (Mechanical) 30 Jul 12 15:44
 I think that this is an "ask your professor" kind of question. We don't do homework on purpose here. David Simpson, PE MuleShoe Engineering "Belief" is the acceptance of an hypotheses in the absence of data. "Prejudice" is having an opinion not supported by the preponderance of the data. "Knowledge" is only found through the accumulation and analysis of data.
 This is not a homework problem. I am a student who is doing summer research. I am building a mathematical model and need help. Thanks.
 IRstuff (Aerospace) 30 Jul 12 16:51
 You start with conservation of energy. The end state has the combined mass of water at some equilibrium temperature and pressure
 GHartmann (Chemical) 30 Jul 12 16:57
 You have to perform a mass and energy balance on the system. Assuming an adibatic system (no heat transfer in or out of your "box") you can calculate the enthalpy in and enthalpy out of the system. Then you have to check the steam tables to see if you have condensed any of the steam in the system. If you have, then try and set some more equations or trial and error calculations to determine the fraction of liquid and gas in equilibrium. Start writing down the equations you know and assigning variables for those you don't. You will learn a lot more this way rather than having someone write down the formulas for you. Good luck
 vpl (Nuclear) 30 Jul 12 17:21
 You might want to look at the forum policies. Student posts in general are frowned upon. While you stated this wasn't a homework post, as GHartman pointed out, part of the learning process is figuring out things rather than having them spoon fed to you. Patricia Lougheed ****** Please see FAQ731-376: Eng-Tips.com Forum Policies: Eng-Tips.com Forum Policies for tips on how to make the best use of the Eng-Tips Forums.
 Thanks IRstuff and GHartmann. I had previously calculated the enthalpy for the water and the steam. I was unsure of what to do with these calculations. My best guess was to add them and see where they fell in the steam tables. I understand where you are going with your post and I need to calculate the quality of the steam in order for my enthalpy calculation to mean anything. I am sorry to have offended anyone on this thread and this forum. The university I attend is currently changing thermodynamics professors and the new one has not started yet. Seeing how this was not a homework problem and I am not getting class credit I didnâ€™t think this was inappropriate. I am actually getting paid for this work. Again I am sorry if this has offended anyone. Thank you for your time.
 zdas04 (Mechanical) 30 Jul 12 18:52
 I would be very surprised if anyone was offended. It is just that all of us have put work into posts that were subsequently deleted because they were homework--not fun. You really have to determine if this is a net condensation or a net evaporation problem. I would look at how much energy would it take to boil all the water and then see what the steam looked like if I removed that much energy (is it still steam, what is the pressure and temperature?). Then I would look at a condensation problem and see how much energy I would need to absorb into the water to condense all of the steam and calculate a new temperature of the water with that extra energy in it. Either the water will still be water or the steam will still be steam. If it turns out that there is enough energy in one or the other stream to completely convert the other then the problem becomes "easy". David Simpson, PE MuleShoe Engineering "Belief" is the acceptance of an hypotheses in the absence of data. "Prejudice" is having an opinion not supported by the preponderance of the data. "Knowledge" is only found through the accumulation and analysis of data.

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