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[billions]

Hi

I calculated piping losses earlier using the darcy-weisbach equation between the 30 & 32" line for the design composition and got ~22m of head. Friction factor assumed was .151 from design calc (unsure if this is right)

My question is that now densities are higher (950-1000 kg/m3). How would I account for this change?

Given,
Re = Diameter * Density * Velocity /Viscosity

Can I say that Density_now/Density_design = 1000/850 = 1.18*Density_Design so reynolds_now = 1.18*Reynolds_design? thus reynolds is still laminar? Hence relative roughness and other factors don't matter asusming they did it right?

So basically, is there minimal change in frictional losses due to density increase?

(I did calculate a power demand increase of 30% by ratio for density change and height using P = Flow * density * gravity * height. Haven't taken the pump or piping classes and I dont have the support atm to be 100% confident in this. Would really appreciate some advice)

Design

Composition: (wt%)
Bitumen: 60%
Water: 30%
fine solid: 10%
air content: 20%
Fluid temperature: 53C
Fluid viscosity: 2400 CP
Fluid density: 1070 kg/m3

Piping Data:
Re: design calc use 400-500
Piping ID: 30 & 32 inches
piping length: 792m (30"), 960m (32")
Velocity: 1.65m/s (30") and 1.45m/s (32")
Piping material: CS, A60k

 

[LittleInch]

billions,

I hate to see a post go unanswered so I'll give this a go.

A couple of things given you're quite new here:
1) Make you post title succinct and interesting otherwise people won't open it
2) you need to provide a bit of context about your issue, your role, where you are, what the project is etc
3) You need to give us a bit more information, calculations etc. What looks like a lot of information has some big holes in it and it's not clear what your points or questions are
4) Try and do some research yourself and say what you've found or if the results confusing.

Now back to your problem.

first your fluid

what is this stuff?? With a two phase fluid (liquid / air) with a liquid comprising mainly bitumen with a viscosity of 2400 cP, you're looking at some thing which the flow equations you quote can't solve.

If you're trying to move some mixture of bitumen at 53 C at 1.5m/sec I find it difficult to believe you're only getting 22m head loss over nearly 2 km of pipe.

You're still in laminar flow regime region, but this stuff is probably not behaving in a manner whereby you can reliably use the flow calculations and may be non Newtonian flow.


Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Latexman]

may be non Newtonian flow

May be??? I'd bet money it is.

Composition: (wt%)
Bitumen: 60%
Water: 30%
fine solid: 10%
air content: 20%

Ugh, that's 120%. What's up with that?

For two phase flow, I'd research similar flow situations and see what works best. If nothing else, the homogeneous equilibrium model (HEM) is a conservative standard used by a lot of industries. Start there, and work towards something reasonable and acceptable in the oil refinery/bitumen world.

Good luck,
Latexman

To a ChE, the glass is always full - 1/2 air and 1/2 water.

 

[LittleInch]

I assumed the 100% was the liquid phase elements with 20% air, though god only knows whether this is bubbles within a glutinous mass or air running over the top of this goo.

Bitumen at 53C is, IMHO, pretty much a solid.


Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Latexman]

Exactly, billions left us guessing. No way to ask an engineering question.

Good luck,
Latexman

To a ChE, the glass is always full - 1/2 air and 1/2 water.

 

[SandCounter]

To directly answer the OP, if the only thing that changed is the density, you will end up with the same head loss. Pressure, however, will change linearly with density.

I used to count sand. Now I don't count at all.