scholarly journals Experimental Analysis of the Extensional Flow of Very Weakly Viscoelastic Polymer Solutions

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 192
Author(s):  
Manuel Rubio ◽  
Alberto Ponce-Torres ◽  
Emilio José Vega ◽  
José María Montanero
Keyword(s):  
Polyethylene Oxide ◽  
High Speed ◽  
Polymer Solutions ◽  
Critical Concentration ◽  
Extensional Flow ◽  
Relaxation Times ◽  
High Speed Imaging ◽  
High Reproducibility ◽  
Molecular Weights ◽  
Viscoelastic Polymer

We study with ultra-high-speed imaging the thinning of the filament formed during the breakup of a pendant droplet of very weakly viscoelastic polymer solutions of polyvinylpyrrolidone (PVP) and polyethylene oxide (PEO). In the latter case, we consider two molecular weights: 10 5 g/mol (PEO100K) and 2 × 10 6 g/mol (PEO2M). The results allow us to measure with high reproducibility extensional relaxation times of the order of 10 μ s. Despite the noticeable differences between PVP and PEO100K, very similar values are obtained for the range of concentrations where the linear elasto-capillary is established. For PEO2M, the extensional relaxation time depends on the concentration even for values significantly smaller than the overlap one. The prediction c low for the concentration below which the linear elasto-capillary regime cannot be reached qualitatively agrees with the results for PVP and PEO2M, while it underestimates the critical concentration for PEO100K. The results for PEO2M are consistent with those reported in the literature for higher concentrations.

scholarly journals Measurement of relaxation times in extensional flow of weakly viscoelastic polymer solutions

2016 ◽  
Vol 56 (1) ◽  
pp. 11-20 ◽  
Author(s):  
Patrícia C. Sousa ◽  
Emilio J. Vega ◽  
Renato G. Sousa ◽  
José M. Montanero ◽  
Manuel A. Alves
Keyword(s):  
Polymer Solutions ◽  
Extensional Flow ◽  
Relaxation Times ◽  
Viscoelastic Polymer

scholarly journals Dilute polymer solution drops impacting on heated surfaces: New impact morphologies and impact regime maps

2017 ◽  
Author(s):  
Volfango Bertola ◽  
Chetan Lakhanpal
Keyword(s):  
Polymer Solution ◽  
High Speed ◽  
Heated Surface ◽  
Polymer Concentration ◽  
Dilute Polymer Solution ◽  
High Speed Imaging ◽  
Satellite Droplet ◽  
Molecular Weights ◽  
Temperature Impact ◽  
The Impact

The impact morphology of dilute polymer solution drops on a heated surface is studied experimentally by meansof high-speed imaging, with respect to the following parameters: surface temperature; impact Weber number; polymer concentration; polymer molecular weight. In addition to impact morphologies observed in Newtonian drops (deposition, rebound, secondary atomisation and breakup/splashing), three new impact regimes have been identified: (i) a single satellite droplet ejected in the direction of bouncing but tethered to the main drop by a thin liquid filament; (ii) a splashing-like behaviour (semi-splashing), where the rim instability  generates  satellite droplets tethered to the lamella by thin liquid filaments; (iii) a spray-like behaviour (semi-spray), where a fine secondary atomisation generated upon impact is quickly absorbed back into the drop globule. Experiments were carried out using drops of aqueous polyethylene oxide (PEO) solutions, with mass concentrations of 100 ppm, 200 ppm and 400 ppm, and PEO molecular weights of 2 MDa, 4MDa, and 8MDa. The impact morphology on a polished aluminium surface with temperatures ranging between 160°C and 400°C was investigated for impact Weber numbers between 20 and 170, taking side view images of impacting drops at a rate of 1,000 frames persecond.DOI: http://dx.doi.org/10.4995/ILASS2017.2017.4905

Experimental Measurement of In-Plane Rolling Nonpneumatic Tire Vibrations Using High-Speed Imaging

2019 ◽  
Vol 47 (3) ◽  
pp. 196-210
Author(s):  
Meghashyam Panyam ◽  
Beshah Ayalew ◽  
Timothy Rhyne ◽  
Steve Cron ◽  
John Adcox
Keyword(s):  
High Speed ◽  
Image Correlation ◽  
Dynamic Mode Decomposition ◽  
Dynamic Mode ◽  
High Speed Imaging ◽  
Correlation Algorithm ◽  
Mode Decomposition ◽  
Series Of Experiments ◽  
Plane Deformations ◽  
Dominant Frequencies

ABSTRACT This article presents a novel experimental technique for measuring in-plane deformations and vibration modes of a rotating nonpneumatic tire subjected to obstacle impacts. The tire was mounted on a modified quarter-car test rig, which was built around one of the drums of a 500-horse power chassis dynamometer at Clemson University's International Center for Automotive Research. A series of experiments were conducted using a high-speed camera to capture the event of the rotating tire coming into contact with a cleat attached to the surface of the drum. The resulting video was processed using a two-dimensional digital image correlation algorithm to obtain in-plane radial and tangential deformation fields of the tire. The dynamic mode decomposition algorithm was implemented on the deformation fields to extract the dominant frequencies that were excited in the tire upon contact with the cleat. It was observed that the deformations and the modal frequencies estimated using this method were within a reasonable range of expected values. In general, the results indicate that the method used in this study can be a useful tool in measuring in-plane deformations of rolling tires without the need for additional sensors and wiring.

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