Hydraulic diameter of finned tube

[crinners]

Hi I read post thread391-248736 and was interested by the post from 25362

Hydraulic equivalent diameter of finned tubes (dHe)


df = external diameter of fin
do = external diameter of bare pipe
p = face-to-face distance between adjacent fins
t = fin thickness

dHe = [(df2- do2)/2p + dft/p + do(1 - t/p)] ÷ [1 + (df - do)/p]

would anyone happen to have a diagram showing this more clearly? I was unsure as to what p would be as a distance, is this circumferential? and if so at which point of the fin?

Thanks

 

[Dougt115]

Look at this site for finned tubes.

http://www.fintube.com/

The simplest way to think of it is that P is the distance between each disk, along the length of the tube.

 

[abeltio]

p = pitch

saludos.
a.

 

[hardingjb]

There are mainly two types of pitches required for heat exchanger application:
One is called a streamlined pitch and the other is a transverse pitch.

I believe your equation is calculating the distance between 2 tubes in the transverse direction which is perpendicular to your stream-flow's path (on the shell-side).

Is your fin-tube's pattern in a parallel or stagger configuration?

Hope this helps.

Jack

http://www.ThermalTransferTechnology.com

 

[EnergyMix]

http://www.chrystyn.co.uk/nextruded.htm

Look at the 3rd drawing. (Note: it uses "s" instead of "p" for pitch, but it's the same dimension. I hope this clears up any confusion.

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