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Adrian Mark
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Join Date: Mar 2009
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How to Calculate Head Loss

03/18/2009 10:58 PM

How do I calculate the head loss in a 200mm dia 30m pvc pipe for a flow rate of 0.19 m3/s of air.
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Codemaster
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#1

Re: How to Calculate Head Loss

03/19/2009 10:07 AM

You need to know the conditions at which the 0.19 m3/s is determined - normal, standard (US or European), actual?

Then you need the actual pressure and temperature of the flowing air. You can then find headloss as for liquid flow using e.g. the Fanning chart, if you take proper care over actual or standard flow, density etc.

Have a go and post your result, along with data above, and I'll post what I make it.

Cheers.....Codey

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Adrian Mark
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#2
In reply to #1

Re: How to Calculate Head Loss

03/19/2009 9:15 PM

I used Darcy-Weisbatch equation to solve this problem, is that OK.

Inlet pressure is atmospheric. density of air 1.23kg/m3, I also used dynamic viscosity of the air as 1.70x10^5 N.s/m2 then found the Renoylds number and found the loss as 5.43m of air column. I am not familiar with Fanning chart. Many thanks
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Codemaster
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#3
In reply to #2

Re: How to Calculate Head Loss

03/20/2009 6:58 AM

That doesn't sound far out.

The Fanning chart is the one that gives friction factor f in terms of Reynolds No. and relative pipe roughness. The chart and the formula it's based on have a few names, Darcy-Weisbach, Moody, Colebrook-White, Nikuradze etc. I haven't got mine to hand but these days I prefer to let the computer solve the equation (sounds like you do the same). I make it 5.5m air assuming roughness 0.05mm but I've assumed actual pipe bore 0.2m and it might be slightly more.

Also leaving pressure drop in terms of m air is a bit unusual and might confuse some. Convert to ~ 65.5 Pa or 6.68 mm wc?

Cheers........Codey

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Anonymous Poster
#10
In reply to #2

Re: How to Calculate Head Loss

06/22/2009 2:27 AM

Hi dear

I am looking for a software by which I can calculate head loss of an air flow in a piping system, you know I want to simulate the piping system completely, I mean with all fittings and by that software I can design or optimise a piping system.

please help me this way if you can

thanks in advance

I want you to answer me through the following email because I am a memeber of this site

thanks anyway

Email: aliabdizadeh@gmail.com
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Anonymous Poster
#4

Re: How to Calculate Head Loss

03/20/2009 8:45 AM

All of the criteria that come into play cause it to be a pointless exercise. Buy a DP guage and 35 meters of tubing for it.
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#5
In reply to #4

Re: How to Calculate Head Loss

03/20/2009 8:52 AM

But what if it's not built yet and you need to design e.g. blower to provide the flow?

If it is built you could put a gauge or water manometer on each end in turn and save 35m tubing.

Cheers.......Codey

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Anonymous Poster
#6

Re: How to Calculate Head Loss

03/23/2009 6:54 AM

use dircy-wishbatch equation for calculation.It will give you head losss.
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Frankston
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#8
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Re: How to Calculate Head Loss

04/30/2009 11:15 PM

Hmmm... are they related to Darcy-Weisbach?

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Codemaster
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#9
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Re: How to Calculate Head Loss

05/01/2009 4:18 AM

Distantly!

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gsuhas
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#7

Re: How to Calculate Head Loss

03/23/2009 11:36 PM

http://www.lmnoeng.com/darcy.htm
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