Pressure Drop Calculation

[funkybrown]

Hi all,

I am hoping someone can help me, now I know I might get some abuse for this, mostly due to the fact it's to do with heating, not refrigeration... but I have been a member a little while now, even if my post count is so very low, and thought if anyone can help it's you guys...

I have seen lots of formulae written on the net, and have tried to add my numbers to them, but to no avail... rather than using a program, I would like to understand it myself!

For this example (although I'm making a spreadsheet with thousands of possible results for all types of fluid) could you please use:

Mass Flow 200 kg/h
pipe length 7100 mm
pipe diam 37 mm
pipe roughness 0.04 mm
density (viscosity) 523.8 kg/m³
Dinamic viscosity 0.0001 Pas
Spec.Heat 2310 J/kgK
Minor loss coeff. 1 (yet to work out an 8coil oval pipe)
Temp in 30°C
Pressure in 50Bar

It may help, but you can calc from those:
Vol. Flow rate 0.3818 m³/h
velocity 0.09865 m/s
friction coeff 0.026907
kinematic visc. 1.909E-07 m²/s
Reynolds 19118.275
boundary layer thickness 0.4161 mm

So please if anyone can calculate and show the working for pressure drop, I would most appreciate it.

Regards
James

[frank]

Quite an easy question for a Design Engineer I would have thought!

Are you really a Design Engineer?

[Brian_UK]

Me, if I was Design Engineer I would use something like this in the absence of a friction loss section from my technical books.

http://www.efunda.com/formulae/fluid...e_friction.cfm

[funkybrown]

Yes I am thanks Frank, well was a design engineer... new job is R&D engineer for a heating company... mostly new stuff to me.

Where my last job was designing cold box type containers at a polystyrene moulding company, i'm now putting process heaters and air heaters on oil rigs and cement factories and anything else that may have a tendency to explode...

So, being honest, I have little to no knowledge of fluid mechanics... give me a year or so and hopefully I will be able to answer everyone else's flow related questions, but for now I am leaning...

As for the calc, thanks Brian, although it is coming out with different answers to the software the company has paid for... strange...

[frank]

Thanks for that.

I'll have a look in my notes, I'm sure I've got the formula somewhere......been such a long time since I used it.......