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Particles in fluid

  1. Mar 29, 2017 #1
    1. The problem statement, all variables and given/known data
    I did an experiment to separate different sizes of starch particles (range of size 1 µm to 10 µm). I mixed the starch powder with water in a long cylinder. I have to create model by using long cylinder to separate those starch particles according to their size (<1µm, <5µm.,<10 µm) with fluid outlet for each sizes.

    I use the Stoke's law to estimate the time of starch particle (for example for size 5 µm) left on top of the solution. but I have a problem on how to calculate/estimate the distance of 90% of 10µm starch particles in fluid (water) reach to the bottom of cylinder? and estimation of time for it to fall at the bottom. I figured out that I can use a Stoke's law but this equation could not use to estimate for how distance for 90% of 10 micrometer of starch particles reached the bottom of the cylinder.
    stokes_law_terminal_velocity.png


    2. Relevant
    equations

    By using the stoke's law I can estimate the time for <5 µm of starch particle left on the top.
    stokes_law_terminal_velocity.png



    3. The attempt at a solution

    Can I use the other relevant equation other than Stle's law to measure the distance of 90% 10µm starch travel until reach the bottom of cylinder?
    I tried to use the equation

    d=Vi(t)+(0.5*a*t2)
    but I think this equation is not relevant to my case.
     
    Last edited: Mar 29, 2017
  2. jcsd
  3. Mar 29, 2017 #2

    Nidum

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    Last edited by a moderator: May 8, 2017
  4. Mar 29, 2017 #3

    Nidum

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    You could start with a very simple model which assumes that the particles all fall separately from each other and that the particles reach terminal velocity almost immediately on entering the water .
     
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