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Leak rate correlation

  1. May 1, 2007 #1
    I am i new member, i hope i am posting in the correct forum. I require some help i with a problem i am trying to solve in my work. Currently we have 3 seperate leak test methods specified for a part all with different working gases and pressures. If possible, i would like to correlate this data so that i can determine that a specified leak rate of "X" with Helium at 700kPa is equal to a leak of "y" with Air at 1.0MPa is equal to a leak of "Z" with R134a at 2.1MPa. The aim being to commonise to one spec (preferably air).
    I have done some work on this to based on info in found around the web, in particular this site:
    I am struggling with a few variables used in the formula, in particular compressability factor and real gas density and a few others of R134a.
    My question, is there another way to go about solving this problem that anyone might be able to help me with? Does anyone know where i can get some properties tables on the web on R134a at different pressures and temps (and helium for that matter) that could also assist me.
    Thanks in advance, any help you can offer will be greatly appreciated.

  2. jcsd
  3. May 2, 2007 #2
    I think that your are concerned about small leaks. If this is the case, the leak rate is determined by the pressure difference and the gas viscosity. And this is the main word: viscosity. It depends on the gas and on the temperature. You can learn about this in wikipedia.
    The reference that you give if for "big" holes.
  4. May 2, 2007 #3
    Thankyou, i will look into this but i still think that i will need some information that i do not have, any oher suggestiong would be helpful.
  5. May 2, 2007 #4


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