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  1. valves4life

    Using Peng Robinson EOS

    I'm so close, I just seem to be off by a bit. Perhaps a kind sir can please tell me where I'm blowing this: let fluid = {}; fluid.critical_pressure=22064000; fluid.critical_temperature=647.14; fluid.omega=0.344; fluid.temperature = 295; fluid.pressure = 101325; fluid.molecular_weight =...
  2. valves4life

    Using Peng Robinson EOS

    Oh I don't really have a MathCad file. I'm doing most of this in javascript, I just used MathCad to try to give me a symbolically solved answer for the V value. I figured it may be able to find one, even though it'll be really complex, I figured there could be a chance, but stepping back and...
  3. valves4life

    Using Peng Robinson EOS

    Wow you've been very helpful! This should be the last question(s), the volume is the molar volume, right?? So I can take 1/density * molar mass and use that as a basis for my starting point? now, here's the biggie, what are the units? I've been using R=8.314413, and pressure in Pa, density...
  4. valves4life

    Using Peng Robinson EOS

    PS here's the PR EOS i'm using... for ease I substituted alpha as p, and P = Pressure, T is obv temp... PPS Mathcad didn't like that equation I tried to solve for V. haha.
  5. valves4life

    Using Peng Robinson EOS

    I do not have access to a simulator.. However, you're seeing that I'm not giving a ton of info, and that's really just because I'm trying to learn HOW to solve this, instead of just saying "here solve this for me!" I think I get it now. When I start the iteration, I'll start out with the...
  6. valves4life

    Using Peng Robinson EOS

    @IRstuff I've realized I was using the wrong equals when doing the mathcad, I found the proper one, and Mathcad refuses to solve PR EOS for V when I do that. :(
  7. valves4life

    Using Peng Robinson EOS

    Ahh. OK sorry about the crosspost. I didn't know what to do with it, so I placed it in both spots. Let's just give an example, let's say I've got Benzene at 300K and 10bar. mol mass = 78.114, Pc=48.95, Tc=562.05, w=0.210 I want to solve for (eventually) speed of sound in this fluid, but in...
  8. valves4life

    Using Peng Robinson EOS

    Hi Everyone, I am very grateful for any answers here, as this is something I've been struggling with for a VERY long time. I've tried over and over to find a solution on my own without any avail. I'm currently trying to get a calculated bulk modulus of substances in order to do a speed of...
  9. valves4life

    Pipeline size VS control valve size

    Thannk you Gentlemen. I understand the sizing limitations on a Triple Offset, and its benefits. This Q was more of a pipleine vs valve size rule. I'm glad to hear there is none. I guess I was told that 2 pipe diameters rule very early on, and for some reason it stuck. Thank you for your...
  10. valves4life

    Pipeline size VS control valve size

    Hey everyone! I have been in a debate with one of our reps, regarding control valve sizing. If I have a 12" line, and a 6" or 8" triple offset valve can do the required flow control (ie it has the CV and it isn't at too far opening angle), should I quote that? Is there a rule of thumb? I was...
  11. valves4life

    Diffuser Plate Sizing

    Stone Cold- I have one last stupid question. Cf, As a flow coefficient. This is not the same as Cv. From http://www.efunda.com/formulae/fluids/calc_orifice_flowmeter.cfm#calc it seems it is defined in texts or through experimentation. I'm unsure what it would be for a simple orifice. If I use...
  12. valves4life

    Diffuser Plate Sizing

    Thank you so much. I think I just needed it to be explained like that. I get it now. I appreciate your time. Thanks Again
  13. valves4life

    Diffuser Plate Sizing

    StoneCold- Right, I figured that would be my route to coming up with overall flow. I think I worded my question wrong- How do I calculate the flow for the hole that I drill. I understand how to calculate total, once I have number of holes and layout, etc. But I just need to know how to...
  14. valves4life

    Diffuser Plate Sizing

    And many of you may notice I started the same thread twice, yes you are correct, I did. I didn't know there was a specific section in the eng-tips forums dedicated to valves. That is 100% my bad. So I made the thread in the pipes and pipelines pages first, then discovered the valve specific...
  15. valves4life

    Diffuser Plate Sizing

    Gentlemen (and Ladies)- My question is fairly simple. I have a consultant that usually does this type of sizing, as I never do diffuser plate sizing. However, I am going on a sales call tomorrow and will not be able to get an answer from my consultant before then. Anyway, the plate will be...
  16. valves4life

    Diffuser Plate Sizing

    Gentlemen (and Ladies)- My question is fairly simple. I have a consultant that usually does this type of sizing, as I never do diffuser plate sizing. However, I am going on a sales call tomorrow and will not be able to get an answer from my consultant before then. Anyway, the conditions I have...

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