Calculation of Pressure rise

Junta_20361
Junta_20361 New Altair Community Member
edited October 2020 in Community Q&A

Hello expert,

  • I have a question about the expression to use when i want to calculate the PRESSURE-RISE in a system which has a pump/fan inside.

As i have gone through tutorial Acu-T 5000: Blower - Steady, it shown that how to calculate pressure rise by:
 PRESSURE_RISE = PRESSURE_outlet - PRESSURE_inlet. (this is STATIC PRESSURE value)


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  • But follow my understanding with Bernoulli's law, the expression should be:

   PRESSURE_RISE = Total_Pressure_outlet - Total_Pressure_inlet

 

Can anyone help me clear this thing? Also correct if i am wrong.
Appreciate any help.
Thanks in advance.

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Answers

  • acupro
    acupro
    Altair Employee
    edited September 2019

    The equation given in the tutorial compares static pressure.  If you want to compare total pressure, then your expression would be correct.  It depends on what you want to compare - static or total.

  • Junta_20361
    Junta_20361 New Altair Community Member
    edited October 2019
    Altair Forum User said:

    The equation given in the tutorial compares static pressure.  If you want to compare total pressure, then your expression would be correct.  It depends on what you want to compare - static or total.

    hi acupro,

    thanks for your answer.

    do you know normally what kind of pressure rise is used when evaluating a pump? static or total?

  • acupro
    acupro
    Altair Employee
    edited October 2019

    My guess would be that static pressure would be typical, as that is simpler to measure, and doesn't obstruct the flow.  Simply drill a hole in the side of the inlet and outlet pipes and put a tube there - flush to the inner/wetted surface.  A total pressure measurement requires a pitot probe - where you install a device that protrudes into the flow and bends such that it points directly into the oncoming flow.  I assume there's no harm in reporting both, but I would guess static pressure rise is typically reported.

  • Junta_20361
    Junta_20361 New Altair Community Member
    edited October 2019
    Altair Forum User said:

    My guess would be that static pressure would be typical, as that is simpler to measure, and doesn't obstruct the flow.  Simply drill a hole in the side of the inlet and outlet pipes and put a tube there - flush to the inner/wetted surface.  A total pressure measurement requires a pitot probe - where you install a device that protrudes into the flow and bends such that it points directly into the oncoming flow.  I assume there's no harm in reporting both, but I would guess static pressure rise is typically reported.

    hi Acupro,

    Thank you very much.

    Your explanation help me clearly understand about this.

    Thanks again.

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