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Anyone work with liquid flow, tubing size flow dependence

  1. Jan 17, 2017 #1
    I want to use a pump to have solution moving through a reaction vessel at a set flow rate. But the problem is the outlets FROM the pump are very small 1/6" (0.4cm) inner diameter, and the vessel INLET is GL14 thread size (1cm inner diameter).







    My question is will a change in tubing size effect the flow rate due to pressure? My initial thoughts are yes, however it is a closed system, so although there is pressure present as the pump "pushes" the liquid through it will after a short period of time equibrilate.

    However when I visualise it the flowing fluid from the small tube will disperse into the big one and there will not be the same flow rate in the bigger tube.

    Any thoughts on this?
  2. jcsd
  3. Jan 17, 2017 #2


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    Volume flow rate will be the same (it's got nowhere else to go).
  4. Jan 17, 2017 #3


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    Mass flow will remain the same . Volume flow will usually remain the same unless the liquid is pressure sensitive (for example soap suds or a volatile chemical)

    Flow velocity will be lower in large pipe than in small pipe .

    Apart from the above it depends on the flow velocity in the small pipe . Low velocity probably no problems at all . Higher velocity possible problems with cavitation and entrained vapour bubbles .
    Last edited: Jan 17, 2017
  5. Jan 17, 2017 #4
    ^^ okay many thanks for the comments! not sure why I got confused on this one, but thanks again for helping clear it up.
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