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  • Joule-Thomson Cooler - Temp/Mass flow rate

    GJvapor

    GJvapor

    @gjvapor-2MyIJF
    Updated: Oct 24, 2024
    Views: 1.8K
    Hello engineers
    I need some help and advice! (I do my internship and I got this task to do. I need it soon, but I got stucked…)

    I am creating some kind of Joule-Thomson cooler.
    Conditions: I have pure Nitrogen in a closed tank under 6000 psi pressure and 190 deg C. When we open the valve the gas will flow in the pipe and cool down by Joule-Thomson effect.

    I know that temperature change depends on the pressure drop.
    So my question is: How can I calculate the Temperature change as a function of Flow Rate (pressure drop per second) for my conditions (6000psi, 190 degC)?!

    I was searching it in some books and internet, but I could find any formula how to do it.
    As far I understand, we need to find Joule-Thomson coefficient at 6000psi, 190degC right?

    Thanks to everybody for any help in advance!
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Replies

  • ISHAN TOPRE

    Member • Feb 20, 2011

    I think it is simple.Let us assume you have 100 m3 of Nitrogen in a closed tank and your flow rate is say 1 m3/sec.You open valve for 1 sec and close it immidiately.
    So you have 99 m3 of Nitrogen remaining in that closed tank,right?
    So your process will depend on following two points,See how the method of calculation is:
    1.Calculate the heat content of 99 m3 of Nitrogen.
    2.The pressure will reduce as you are removing gas.Calculate that temperature now.

    The process is a constant volume process.If you have experimental apparatus you can very well try for different values.Else you can go for theoretical method as I have described.
    Please correct me if I am wrong.
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  • GJvapor

    Member • Feb 21, 2011

    [​IMG]

    This system has constant ambient temperature of 180 degC. The nitrogen in the tank has 4000psi and 180 gedC. I need to cool this aluminum mass from 180 degC to 170 degC! (Let's say in 20mins)

    If my flow rate is very small I will probably not notice any change in the temp. If its to big the mass will cool down to lower temp. then needed.

    So how to find the right flow rate?
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  • ISHAN TOPRE

    Member • Feb 21, 2011

    I will need to think on it.But if you have got apparatus can you perform trial and error?I will certainly help but will require time.😀
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  • ISHAN TOPRE

    Member • Feb 22, 2011

    I got a brain wave.You say temperature of system is 180 deg C constant?
    And you want to reduce temperature of aluminium block to 170 deg C right?
    Then calculate heat lost by Aluminium =m*c*dT....where c is joule constant as you said.
    When you pass nitrogen the
    heat gained by =heat lost by
    nitrogen aluminium
    This equation will involve volumetric flow rate of nitrogen so that you can easily get your answer.
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  • GJvapor

    Member • Feb 22, 2011

    Yo, thats good advice! Thanks!

    I do it now, but need some help... how to calculate flow rate which is needed to keep the Temperature at constant 170 degC.
    Can not get the formula...grrr

    Thanks for help!
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  • ISHAN TOPRE

    Member • Feb 23, 2011

    GJvapor
    Yo, thats good advice! Thanks!

    I do it now, but need some help... how to calculate flow rate which is needed to keep the Temperature at constant 170 degC.
    Can not get the formula...grrr

    Thanks for help!
    My friend you don't need to know flowrate at 170 deg C.
    Because it is variable in the equation.You will get it as you will solve this equation.
    😀
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