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Throttling Process

  1. May 5, 2006 #1
    dear all

    What is the throttling Process?
    what is Joule homson Effect?
  2. jcsd
  3. May 5, 2006 #2


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  4. May 5, 2006 #3
    A throttling process is a process that is isenthalpic. Thus, [tex] h_1 = h_2 [/tex]. This means that the following is also true, [tex] u_1 + P_1 v_1 = u_2 + P_2 v_2 [/tex]. So if you drop pressure in a throttling value, you increase the internal energy, and vise versa.

    The Joule -thomson- effect deals with the fact that as you expand a gas it looses temperature. Note that for hydrogen; however, it gains temperaturee as it expands. This makes hyrdogen particularly dagnerous.
  5. May 7, 2006 #4
    Pressure drops in CNG kit Pressure regulator from 300 bar to 4 bar in 1st chamber due to expansion is it throttling process? temperature also drops in it.
  6. May 7, 2006 #5
    Yes, that is exactly what it is.

    Edit: wait, what do you mean by expansion? Is it going through a nozzle?
  7. May 8, 2006 #6
    no it is going throug valve (sloninoid valve) from storage cylinder through high pressure pipe into solinoid valve and then in the 1st stage chamber of pressure regulator.
  8. May 8, 2006 #7
    Yes, it is a throttling valve.
  9. May 8, 2006 #8
    what is the value of joule-thomson coefficient for methane
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