Liquid Slug Mixing in Pipeline 3

[MikeAshburner]

Some years ago I remember seeing a formula in the Transaction of the UK mecahnical engineers (I think) that gave a formula for the inter mixing at the interface between two liquid slugs in a moving liquid pipeline. (the liquids are moving with turbulent flow).
Can anyone help?

 

[MikeHydroPhys]

you could treat the slugs as shearing solids, plastic and the rotation as a integral mass shearing through the fluid of high viscous state and the fluid as a low viscose material and then resolve the interface as a thixotropic from plastic material, then add information re: displacement. I too remember something on this and the only people I suggest you track through are G. Tchobanoglous: Metcalfe and Eddy Wastewater Transport,the Igneous flow volcanic lava tube researchers and some of the soil pipe flow and agricultural systems to try and relocate the reference off their discussed items. This leaves the Bagnold flow principle. The point about geologic and hydraulics people is they get into lots of physics to find resolutions for flows in soils and rock and associated features so they sometimes list references fluids and mechanics stress experts have studied. Nice problem. Interested in the result when found.
MikeHydroPhys

mdshydroplane

 

[jmw]

Might it have been BPA? (British Pipeline Agency?) and you may get more data from the petroleum engineetring threads as this is a key issue in multi-product pipelines.

JMW

http://www.viscoanalyser.com

 

[25362]

I'm not sure whether the following will satisfy the query raised by MikeAshburner. Anyway, from my own sources...

The flow-rate in multi-product (e.g. a sequence of naphtha, gasoline, kerosine, gas oil, kerosine, gasoline, naphtha) pipelines has a direct bearing on the extent of intermingling of successive products.

In the first place the Reynolds Number should be well in the turbulent region (Re >> 2000-3000) because laminar flow would result in complete mixing of products.

It has been established that there is a higher critical value of the Re at which the intermixing rate drops sharply, as follows:

pipe dia, inches Critical Re

4 22 000
6 29 000
8 34 000
10 40 000
12 46 000
14 72 000

In addition:

Switching into appropriate tanks at products' destination is based on readings by interface detectors, which measure specific gravity, dielectric constants, viscosities, etc.

Special interface holding tanks are provided to accept interfacial mixtures of two products until these can be disposed of, usually by blending into a large volume of a compatible product in a proportion that will not put that product off spec.

Sometimes, synthetic rubber spheres are introduced through special launchers into the pipeline at its origin when switching from one product to another.