Paper Number
NF16 

Session
Non-Newtonian Fluid Mechanics & Instabilities

Title
Viscosity measurement of rapidly evolving biopolymer solutions and modeling of laminar pipe flow – mixing, MRI-velocimetry, and simulation

Presentation Date and Time
February 15, 2017 (Wednesday) 4:00

Track / Room
Track 2 / Audubon A

Authors (Click on name to view author profile)

1. Hartt, William H. (The Procter & Gamble Co)
2. Tozzi, Emilio (The Procter & Gamble Co)
3. Joshi, Shripad D. (The Procter & Gamble Co)
4. Johnson, Robert D. (The Procter & Gamble Co)
5. Bacca, Lori A. (The Procter & Gamble Co)

Author and Affiliation Lines (in printed abstract book)
William H. Hartt, Emilio Tozzi, Shripad D. Joshi, Robert D. Johnson, and Lori A. Bacca
The Procter & Gamble Co, West Chester, OH 45040

Speaker / Presenter 
Hartt, William H.

Text of Abstract
Rapidly evolving rheological properties are prevalent in processing applications with dissolving or reacting polymers. When polymeric particles are incorporated into solvents, viscosity changes of 1000x may occur in seconds. These dramatic changes in viscosity present challenges for process control, mixing, and scale-up. We present techniques and results for measuring rapidly changing viscosities in non-Newtonian fluids and modeling flows with rapidly changing viscosities. We also present flow imaging for validation of models.

First, NMR-velocimetry is used to show the effects of rapidly changing viscosities on laminar flows in process equipment. This information is used to formulate a model that determines transport properties needed for scale-up and prediction of equipment performance. Impacts of rapidly changing viscosity on laminar pipe flow are shown experimentally.

Second, after determining which time dependent transport properties are needed for objective scale-up we demonstrate and validate a method for measuring time dependent viscosity. We use analysis utilizing the Metzner-Otto rule for stirred tanks (impeller in a rheometer) and flow through static mixers. Both methods result in similar viscosity and time dependent measurements. We explore time dependent growth models from various technical fields to best fit the data. We also use these models to objectively determine temperature and strain rate dependence. The resulting models are then used in a variety of flow models.

Finally, we present laminar pipe flow models with three levels of hierarchy. Dimensional analysis leads to scaling behavior and we are able to collapse all data onto one master curve. The second level of complexity is the axially dependent evolving viscosity flow model, which is easy to use and predicts many features of the flow. The final level of complexity is a three-dimensional CFD model with evolving viscosity. We show the accuracy and practicality of using each of these models.