Bench to production scale calculations (high viscous flow)

[aspearin1]

I am doing a bench scale experiment, intended to mimic larger scale production flow. I am using a fluid that is 13,000 cps and pushing it through a section of tubing from a pressure vessel controlled with compressed air. So far I am getting good results. The data I have are Pressure; mass flowrate; viscosity; temperature; density; and tube dimensions. From this I can calculate Volumetric flowrate and bulk velocity.

My problem comes in the scale up of the system. I'd like to take the data from this system which has an outlet port of 1/8" ID and scale it (to the best possible fit) to a system which has an outlet of 2" ID. It is my personaly belief that bulk fluid velocity would be the same for these different pipe ID's at the same pressure, (assuming similar losses due to friction). If P=M*v and (M)momentum is conservative, then ideally, if (P) pressure is kept constant, then so should (v)velocity, correct? If this is true, then in the smaller diameter tube, I will have the same velocity, but lower flow compared to the larger ID pipe. Is this rationale valid? Also, can anyone suggest a useful fluid dynamics book or resource? Preferably one less calculus based and more algebraic and fundamental... Or is there a useful bench-pilot-production scale-up handbook?

aspearin1

 

[25362]

While searching for modeling in pipe flow and dimensional analysis I found this site that hopefully may be of help:

http://www.hyle.org/journal/issues/6/vanbrak.htm

Good luck.

 

[Latexman]

The fluid flow reference I recommend is Crane Technical Paper (TP) 410. You can buy it for US$ 45 over the internet at:

http://www.abzinc.com

Please get it and read it before trying to solve the scale-up problem. Based on your discussion above, you've used the right words, but it's obvious from the way you've put the words together, you don't know enough about what you are doing right now. You need help.


Good luck,
Latexman

 

[quark]

Your assumption(velocity remains constant) is correct except that it follows Bernoulli's principle rather than momentum. Momentum is a redundant charesteristic in this aspect.

There are three flaws in your theory.

First one is that Pressure is not equal to momentum times velocity. It is rather time rate of change of momentum per unit area. (do a dimensional analysis and you will come to know)

Secondly, linear momentum is not always conserved. For example linear momentum is not conserved in inelastic collision. It is angular momentum that is always conserved.

Third one is that friction will be different in the two cases, for frictional resistance is inversely proportional to the diameter of the pipe.

Regards,


Eng-Tips.com : Solving your problems before you get them.

 

[ajsee]

Perry's Chemical Engineers' Handbook is usually good for less calculus based and more algebraic and fundamental equations.