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Pressure Drop across Orifice
Last Post 18 Nov 2012 02:43 AM by pfeinstein. 6 Replies.
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suvin
New Member
New Member
Posts:4

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02 Jul 2012 03:41 AM
    Dear All,

    I would like to know the minimum parameters required for predicting the Pressure drop across an orifice plate . The values of upstream pressure ,Pipe size and Orifice diameter is enogh to predict the pressure drop ? Do the pressure drop remains same if we devide the total hole area to "n" number of holes ? Please let me know your comments .
    Nathaniel
    Basic Member
    Basic Member
    Posts:193

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    03 Jul 2012 02:36 PM
    No it is not enough information. Look at the Bernoulli equation. It will help you determine what information you need.

    http://en.wikipedia.org/wiki/Bernoulli%27s_

    velocity^2 + 2*pressure/density= constant across an orifice.

    Niel Leon
    engineering.com
    waqas439
    New Member
    New Member
    Posts:1

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    06 Jul 2012 11:04 PM
    the upstream pressure along diameter information is not enough ,it at least require the downstream pressure.
    Second i want to answer wither pressure will remain constant ,NO
    pressure is simply given by force per unit area so if you place a pipe of larger dia into n N number of smaller pipes there will more friction under the same flow rate so there will more pressure drop.
    for further inquiry write me at waqas439@gmail.com
    Nathaniel
    Basic Member
    Basic Member
    Posts:193

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    11 Jul 2012 02:51 PM
    waqas:

    In the second question think that suvin was asking about if the pressure drop would be different if there were the total area was distributed across a number of orifices instead of only one. It was not a question about what would happen flow was distributed across a number of pipes.

    You are correct that the pressure drop along the length of smaller pipes will be greater will be greater for the smaller diameter pipes because of frictional effects because of both surface frictional and internal frictional effects. The internal frictional effects are a function of the Reynolds Number.

    Getting back to the first question and my answer for suvin's first question, the diameter of the pipe has no effect on the pressure drop across the orifice.

    Niel
    suvin
    New Member
    New Member
    Posts:4

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    18 Jul 2012 02:30 AM
    Niel & Waqas,

    Thank you very much for your response. My intension is to find out the maximum pressure drop across circular plate with drilled holes which is mounted in pipe line. I have the data of pipe size,Upstream & downstream pressure,flow rate etc.Is there any methode to predict the pressure drop ?
    jakestenson
    New Member
    New Member
    Posts:1

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    12 Oct 2012 09:39 AM
    <a href="http://www.proflow.ca/flow-instruments/flow-meter/nuflo-orifice-plate.html">Information about orifice calculations here</a>
    pfeinstein
    New Member
    New Member
    Posts:16

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    18 Nov 2012 02:43 AM
    Suvin: you have a calculator on the efunda site for doing these calculations. You'll find the input parameters there, which include the piping data and related engineering vairables you refer to.

    _________________________________________________________________
    My interests include exotic alloy valves from The Alloy Valve Stockist, Barcelona, Spain at http://alloy-valves.com
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