The use of a shear-thinning polymer as a bubbly magma analogue for scaled laboratory experiments

T. J. Jones*, E. W. Llewellin, H. M. Mader

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)

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Abstract

Analogue materials are commonly used in volcanology to perform scaled laboratory experiments. Analogue experiments inform on fundamental fluid dynamic, structural and mechanical processes that are typically very difficult to observe and quantify directly in the natural volcanic system. Here we investigate the suitability of an aqueous solution of hydroxyethyl cellulose polymer (HEC) for use as a lava/magma analogue, with a particular focus on its rheological behaviour. We characterize a range of physical properties as functions of the concentration and temperature of the solution: density; specific heat capacity; thermal diffusivity; thermal conductivity; surface tension; as well as rheology. HEC has a non-Newtonian, shear-thinning rheology that depends on the concentration and temperature of the solution. We show that the rheology is well described by the Cross model, which was originally developed for polymer solutions, but has also been applied to bubbly magmas. Using this similarity, an approach for scaling analogue experiments that use shear-thinning polymers, like HEC, to bubbly magma is presented. A detailed workflow and a spreadsheet are provided to allow experimentalists to investigate the effects of non-Newtonian behaviour in their existing laboratory set-ups. This contribution will allow for the more complex, but often more realistic case of bubble-bearing magmas to be rigorously studied in experimental volcanology.

Original languageEnglish
Article number106768
Number of pages14
JournalJournal of Volcanology and Geothermal Research
Volume392
Early online date11 Jan 2020
DOIs
Publication statusPublished - 15 Feb 2020

Keywords

  • Analogue experiments
  • Bubble suspension
  • Cellosize
  • Hydroxyethyl cellulose
  • Scaling
  • Shear-thinning polymer

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