Highlighting Thermo-Elastic Effects in Confined Fluids.
Eni Kume1, Patrick Baroni1, Laurence Noirez1
1Laboratoire Léon Brillouin (CEA-CNRS), Université Paris-Saclay, CEA-Saclay, CEDEX, 91191 Gif-sur-Yvette, France.
Polymers
|July 24, 2021
Summary
Researchers discovered solid-like thermal behaviors in liquids using a novel approach. Applying shear fields revealed dynamic thermo-elasticity, with cold and hot bands appearing in fluids like polybutylacrylate.
Area of Science:
- Rheology
- Thermodynamics
- Fluid Dynamics
Background:
- Recent studies identified finite shear elasticity in mesoscopic fluids, suggesting liquids can exhibit solid-like properties.
- This finding motivates further investigation into other mechanical and thermal characteristics of liquids.
Purpose of the Study:
- To explore the dynamic thermo-elastic behavior of liquids under mechanical shear.
- To investigate the conversion of shear strain energy into thermal variations within fluids.
Main Methods:
- An innovative thermal imaging technique was employed to analyze liquids subjected to low-frequency mechanical shear.
- Three distinct fluids were tested: polybutylacrylate (PBuA), polypropyleneglycol (PPG), and glycerol.
Main Results:
- A dynamic thermo-elastic mesoscopic behavior was identified in the tested fluids.
- A portion of the shear strain energy was converted into observable cold and hot shear bands.
- These thermal bands fluctuated synchronously with the applied shear field.
Conclusions:
- The observed thermodynamic changes indicate a coupling between shear strain and elastic modes in liquids.
- This supports theoretical predictions and experimental evidence of low-frequency shear elasticity in mesoscopic fluids.
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