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  1. #1
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    Red face How to calculate the Flow rate of air blower(centrifugal type)


    Please tell me the formula of flow rate of air blower (centrifugal type).

    Regards
    Nadeem



  2. #2
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    Re: How to calculate the Flow rate of air blower(centrifugal type)

    Sorry, we are not manufacturers of ventilation fans here.

    I suggest you ask somewhere else as this is a refrigeration forum.
    Brian - Torquay, Devon, UK
    I have to stop saying "how stupid can you be?" to my co-workers.
    They're starting to take it as a challenge...

    BASIC MAINTENANCE. If it doesn't move and it should then use WD40. If it moves but it shouldn't then use Duct Tape.

  3. #3
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    Re: How to calculate the Flow rate of air blower(centrifugal type)

    There are generally two possibilities that i know. One is to measure the air velocitiy in the attached duct work. Using the formula volume flow=hydraulic area (ductwork)* measured velocity, will give you the answer. The other possibilty is to utilize the the absorbed power vs. volume flow / differential pressure chart of the fan manufacturer. Therefore you have to measure the absorbed power of the fan motor. Hope that helps.

    regards

    Entropie
    RTFM always thoroughly!
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    Re: How to calculate the Flow rate of air blower(centrifugal type)

    hi all
    the formula is Pt= Ps+Pv
    Pressure total = Pressure staitis + pressure velocity
    or
    quantity= area*volume
    if the duct is 2 metres by 2 metres volume is 2 metres/second
    = 2x2=4 x 2m/sec= 8 cubic metres/second x that by 1000 = 8 litres a second

  5. #5
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    Re: How to calculate the Flow rate of air blower(centrifugal type)

    Quote Originally Posted by cool_tech View Post
    hi all
    the formula is Pt= Ps+Pv
    Pressure total = Pressure staitis + pressure velocity
    or
    quantity= area*volume
    if the duct is 2 metres by 2 metres volume is 2 metres/second
    = 2x2=4 x 2m/sec= 8 cubic metres/second x that by 1000 = 8 litres a second
    I think you mean velocity not volume.

    8m3/s = 8000l/s
    I'm back on the Pale

  6. #6
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    Re: How to calculate the Flow rate of air blower(centrifugal type)

    CFM = Q/1.08 x TD

    Q = Total BTU or another way is this:
    http://www.1728.com/flowrate.htm

  7. #7
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    Re: How to calculate the Flow rate of air blower(centrifugal type)

    His question is how much air will a centrifugal fan produce, not how to measure it in a duct.
    Brian - Torquay, Devon, UK
    I have to stop saying "how stupid can you be?" to my co-workers.
    They're starting to take it as a challenge...

    BASIC MAINTENANCE. If it doesn't move and it should then use WD40. If it moves but it shouldn't then use Duct Tape.

  8. #8
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    Re: How to calculate the Flow rate of air blower(centrifugal type)

    Volume flow rate = Area of the duct X velocity

    remember area = pie X diameter squared/ 4

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    Re: How to calculate the Flow rate of air blower(centrifugal type)


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    Re: How to calculate the Flow rate of air blower(centrifugal type)

    i too have an blower...its 550 cub.mt per min, and t manufacturer says a value 60mmAq...
    I am not sure as to what pressure value to be taken if I use ideal gas law to calculate mass/molar flow rate to calculate air velocity

    pls suggest

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