Pressure drop in half pipe coils

[StoneCold]

I am looking for a method to calculate the pressure drop in half pipe coils like the ones used as heat transfer jackets.

See my posting in Piping and fluid mechanics.
I would link the thread but I can't seem to figure that out.


Thanks

StoneCold

 

[25362]

One has to estimate the hydraulic diameter and the friction factor.

The hydraulic diameter,

D_h = 4(fluid flow cross section) / wetted perimeter​

The friction factor, from literature,

f = 0.076 Re^-0.25 + 0.0073(D_h/D_c)^0.5 [±] 10%​

valid for 0.34<Re(D_h/D_c)²<300, where D_c is the coil diameter.

The friction drop is estimated from:

[&Delta;]P_f[&asymp;] 4 f [&rho;] (L/D_h) (V²/2)​

where [&rho;] is the liquid density; V, the linear velocity; Re, the Reynolds number; L, the coil length.

 

[StoneCold]

Thanks 25362

Best Regards
StoneCold

 

[MJCronin]

Stone....

I have always used a pipe with an inside "wetted perimeter" equvalent to that of the half-pipe. Then I have used the calculated half-pipe lengthe and treated this as a piping problem.

There are tables/methods available for piping pressure drop...

How much of a difference in calculated pressure drop will this make ?

-MJC