(adsbygoogle = window.adsbygoogle || []).push({}); Hey! You seem to kn ow what youre talking about here and im stuck on a similar question, so is it ok if i ask you something? ReaverKS said: ↑I've attached a picture that is essentially the setup for the problem. There's really only one other major obstacle to overcome and that is that the states are not fixed. I.e. state 1 all you know that is obvious is that P1=0.1Mpa=100kpa but you need to know something else to be able to start doing some calculations. My advice is to open your book or notes and look for the basic definition of quality. Once you get the quality, with knowing the pressure the state is fixed and you can easily calculate anything you could want (including internal energy, u1). State 2 also needs to be fixed, they give you x2=1, you have to read the problem carefully to gather this information. You need to know more information about state 2 in order to fix it, so that you can calculate other information about state 2, such as u2. You can actually calculate v1 and you know that v1=v2 because it's a closed system, and I assume the vessel to be rigid, therefore V1=V2 and v1=v2. Now you know x2=1 and v2=v1 which you can calculate v1 if you know x1. Now you've got state 2 fixed and you can calculate the quality at state 2, then you can calculate the internal energy at state 2. Then by utilizing the first law, you just need to determine what the work is, look at my post above for the general formula for a closed system for work. Notice that this is an isometric system (constant volume) so what does that mean about dV?

Basically I found your tips on things that you need to include when solving the question really helpful, and I was wondering, should you sketch graphs of specific volume against pressure, temperature, etc, or should you just use regular volume, or both?

And I was wondering, how do you identify a isentropic problem?

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# Thermodynamics: P,V,T graphs and other misc. questions.

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