Why:
To study the effect of preshear on the transient evolution of the microstructure and viscoelastic tensile stresses for monodisperse dilute polymer solutions.
To generate previously unattainable scientific data for dilute viscoelastic polymer solution in a broad subclass of transient extensional flows.
How:
Impose a well define and controlled preshear history (from no preshear to very strong pre-shear) for a specified period of time. The shear flow is halted and an exponential increasing elongation profile is applied axially to the polymeric liquid bridge while measuring several key quantities: tensile force, midpoint radius and fluid filament profile evolution.
This will allow a quantitatively measure of the effects of preshear to be generated for viscoelastic polymer solutions.
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Stretching of a Polymeric Liquid Bridge in Plateau tank
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Stretching of a Polymeric Liquid Bridge in Microgravity
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Impact/Benefits:
Optimization of polymer processing operations that involve complex flows, I.e., Both shearing (”rotation”) and elongation (“stretching”)
Applications include shearing in spinneret prior to fiber spinning of both synthetic and natural polymers (e.g., Lycra, Kevlar, spider silk) complex flows such as polymeric drag reduction and shearing and stretching in extruder and nozzles.
Shear History Extensional Rheology Experiment (SHERE)
Next Flight Experiment: MABE
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