John Abbott Mathematics in Industry Workshop 06/16/2008 MTE-AMA Elongating Bubble in an Accelerating Extensional Flow.

John Abbott

Mathematics in Industry Workshop 06/16/2008

MTE-AMA

Elongating Bubble in an Accelerating Extensional Flow

2June 2008Mathematical Problems in Industry June 2008

Outline

• Introduction to Corning!• Brief Problem Statement• Background, Introduction, and Context

– Pictures

– References & Previous work

• Restatement of Problem• Extensions, further work which might be possible


Corning Incorporated

• R&D labs celebrating 100th year anniversary• Corporate member of IMA at Univ. of Minnesota• Emphasis on innovation and new products

– Light bulb: worked with Edison, all incandescent light bulbs in the world are made by the high speed ‘ribbon machine’ developed by Corning

– Glass for Cathode Ray TVs (CRTs); color TVs– Silicones – spun off to Dow-Corning (private company)– Fiber glass insulation – spun off to Owens-Corning Fiberglas– Optical Fiber – low cost, low attenuation optical fiber for

telecommunications– Precision glass for LCD flat panel displays– Extruded Ceramics for catalytic converter substrates– Specialty glass & ceramics (mirror blank for Hubble telescope)


Environmental Products

Corning makes ceramic ‘substrates’ catalytic converters for cars

The substrate is made by extruding wet ceramic through a die with hundreds of holes – the holes need to be uniform.

In drilling the holes the drills used to wear out..


Display – Large Glass Sheets for LCD displays

Corning invented a process for making sheet glass where the glass flows over two sides of a ‘weir’, so that the final sheet has two pristine surfaces.

Gen 8 2160x2460mm

Gen10 3000x3000m

0.7mm thick


Optical Fibers

One of Corning’s big businesses

is optical fiber – essential to the internet.

The combustion synthesis process used to make pure SiO2 was developed by Franklin Hyde at the Corning R&D labs, the same fellow who invented silicones. The same process is used to make windows for the space shuttle and the glass for the Hubble space telescope.

GeO2 &SiO2 – optical fibers

TiO2 & SiO2 – low thermal expansion


Optical Fiber


Outline


– Pictures




Problem Statement

How is a single spherical bubble or ‘seed’ stretched as it moves down the tapering root during a high speed optical fiber draw process?

The leading tip of the bubble sees an exponentially increasing velocity (and extensional rate). How (if at all) does the shape differ from the distortion in either simple shear flow or simple extensional flow.


Outline


– Pictures




“Blisters” in volcanic magma

Rust, Manga, Cashman 2003


Experimental measurement of bubble shapes

Rust, Manga 2002

An optical fiber airline has a large aspect ratio l/a


Previous Analysis (Hinch & Acrivos papers)

[11] Hinch, E.J., and Acrivos, A., “Long slender drops in a simple shear flow”, Journal of Fluid Mechanics Vol. 98 Issue 2 (1980) pp. 305-328.

Some differences between ‘simple shear flow’ and ‘simple extensional flow’


Previous Analysis (Howell & Siegel papers)[15] Howell, P.D., and Siegel, M., “The evolution of a slender non-axisymmetric drop in an

extensional flow”, Journal of Fluid Mechanics Vol. 521 (2004) pp. 155-180..

Both Howell-Siegel and Hinch-Acrivos predict the pointed ends to the elongating bubbles which is seen in practice.


Generic Draw Model –use Huang/Miura/Wylie where possible.

[9] Huang, H., Miura, R.M., and Wylie, J.J., “Optical Fiber Drawing and Dopant Transport”, submitted to SIAM J. Applied Math 2008

www.math.yorku.ca/Who/Faculty/hhuang/preprints/DopantFinal.pdf

Where log R vs. z is convex, heat is going into blank.

Where log R vs. z is concave, heat is coming out.

Because of cylindrical geometry 2D plot does not show cross-sectional area.

dT/dz=0 determines ‘inflection’

log R


Velocity U(z) and extension rate dU/dz

z

(du/dz) log u(z)

z

We can approximate u(z) by something convenient: exponential heating, exponential cooling.


Input to problem

Need assumed V(z) and dV/dz.

Blank shape D(z), velocity V(z), and temperature T(z) all need to be consistent.

JSA to provide base model.


Outline


– Pictures




Problem Statement

How is a single spherical bubble or ‘seed’ stretched as it moves down the tapering root during a high speed optical fiber draw process?


Outline


– Pictures




Thank you!

John Abbott Mathematics in Industry Workshop 06/16/2008 MTE-AMA Elongating Bubble in an Accelerating Extensional Flow.

Documents

mathematical problems

corning glass

optical fiber slide

possible slide

industry workshop

thick slide

sheet glass

optical fiber essential