Recent content by longz

  1. longz

    Pressure loss to double wall pipe (ventilation)

    Hi Chestermiller, Thank for advices, you are correct. I changed the value of the viscosity and the software output similar to mine calc. To pressure drop of inner pipe support ring, could you please advise some instructions ? I considering this is multi-hole orifices plate but the point is the...
  2. longz

    Pressure loss to double wall pipe (ventilation)

    Hi Chestermiller, I found a online calculator exactly same to this matter but the result is quite different in Reynold number (509853 versus with 4988 as mine calc.) caused me confusing, can you please have a look and advise the reason? below is the link of software and information...
  3. longz

    Pressure loss to double wall pipe (ventilation)

    Hi Chestermiller, I made a study and draft a calculation to pressure drop but I not sure it is correct 100% or not, can you please have a check and correct me if i was wrong something. thank
  4. longz

    Pressure loss to double wall pipe (ventilation)

    I really sorry as I can't get this book, can you advise the specific mathematic formula ?
  5. longz

    Pressure loss to double wall pipe (ventilation)

    I have no idea, can you provide some instructions ? thank
  6. longz

    Pressure loss to double wall pipe (ventilation)

    Hi Chestermiller, I need to determine the pressure drop to the air. Thank
  7. longz

    Pressure loss to double wall pipe (ventilation)

    Hi every body, I need help to calculate the pressure drop to double wall pipe with information as below, i understand need calculate pressure loss to the straight pipe, elbows and supports but I don't know exactly how. - Fluid : air - Double wall pipe (stainless steel) with outer pipe...
  8. longz

    Sizing fan static pressure to open a cover

    Thank Malemk for your advises. The ducting system has just updated with an equipment installed at the outlet of the fan with back pressure 40 mBar !. the fan now come to quite huge . I come up with an solution use available compressed air to push the cover open and the fan just blow air out...
  9. longz

    Sizing fan static pressure to open a cover

    Thank Nidum, the balanced door look not suitable to this case as the hinge axis is horizonal not vertical as door. I'm thinking a counterweight on the cover may works.
  10. longz

    Sizing fan static pressure to open a cover

    Hi Baluncore, Thank a lot for your guides. I have some queries about your calc., Sin( 15° ) or Sin( 20° ) is correct ? the duct mouth chamfer 5° therefore cover open with an angle 20° to vertical axis. The result 63.8354 Pa is static or dynamic pressure ? if this is dynamic so how to find the...
  11. longz

    Sizing fan static pressure to open a cover

    Hi all great PF members, Can anyone help me to sizing fan static pressure strong enough to open a metal cover an angle 15 degree at the end of the duct (20m in length with few 90 degree bends), I'm really not good at math so any help are greatly appreciated. Please refer to sketch attached for...
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