0
$\begingroup$

I have a pipe with ID=75 mm interrupted with an array of N=121 tubes (as shown in the drawing), forcing the air to flow inside the tubes (ID of each tube is 2mm) spaced apart by 5mm. Length of tubes is 50mm. How do I estimate the pressure drop for the outcoming air? If there is a white paper on this, I would appreciate a reference! My application would benefit from maximizing the N of tubes and reducing their IDs, but I need to know when to stop (i.e. when the air pressure drop becomes impractical).

I am aware of this thread which treats a different configuration (cross-flow around the tubes):

Method for computing the pressure drop across a bank of tubes enter image description here

Improve this question
$\endgroup$
3
  • 2
    $\begingroup$ Is it not as simple as working out the pressure drop for one tube ? $\endgroup$
    – Greg Locock
    Commented Feb 11 at 22:10
  • $\begingroup$ Greg, -- should it be like parallel resistors then? $\endgroup$
    – runcyclexcski
    Commented Feb 12 at 16:00
  • 1
    $\begingroup$ I suppose it is, yes. $\endgroup$
    – Greg Locock
    Commented Feb 12 at 20:47

1 Answer 1

Reset to default
1
$\begingroup$

Try using this calculator to calculate the flow rate for one tube at a given pressure drop and then multiplying the flow rate with the number of tubes, the calculator has an explanation akin to a whitepaper. The calculation is based on the darcy-weisbach method which is well documented.

You are also likely to have entry and exit losses for the pipework, having a radius on the inlet is a good idea. I will let you know if I find a source.

Improve this answer
$\endgroup$
4
  • $\begingroup$ I expected the this to behave as resistance of parallel resistors -- R(n) -- 1/R1 + 1/R2 + ... + (1/Rn) -- is this what you mean by multiplication? $\endgroup$
    – runcyclexcski
    Commented Feb 12 at 16:00
  • 1
    $\begingroup$ @runcyclexcski the pressure drop i believe is the same across all pipes, its the flow rate that you multiply by the number of tubes, i edited my answer. $\endgroup$
    – Sami Safarini
    Commented Feb 12 at 18:03
  • $\begingroup$ source:abe-research.illinois.edu/faculty/dickc/Engineering/… $\endgroup$
    – Sami Safarini
    Commented Feb 12 at 18:04
  • $\begingroup$ You can calculate the pressure drop for various flow rates. $\endgroup$
    – Sami Safarini
    Commented Feb 12 at 18:13

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.