A new elongational rheometer for polymer solutions

Schümmer, P.; Tebel, Karl Heinz

doi:10.1016/0377-0257(83)85006-x

Cited by 85 publications

(55 citation statements)

References 10 publications

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“…It was found that the measured relaxation time decreases with increasing jet velocity, reaching a plateau for sufficiently high velocities. This behaviour was related to the influence of the initial amplitude disturbance as reported in [6][7][8]. The higher jet velocity was imposed, the larger initial amplitude was observed on jet images and the lower relaxation time was measured in agreement with [6][7][8].…”

supporting

confidence: 56%

“…6-b), the inflection after SP = 1.5 is far less pronounced than for higher velocities and the subsequent increase of SP is far more pronounced. Equation (8) indicates that high values of SP are due to a combination of a high dmax/D1 ratio and a non-negligible parameter (t). Therefore, contrary to the previous case, the surface-area of the system at breakup is not brought by spherical beads only and the contribution of the string is not negligible anymore.…”

Section: Figure 4 Presents the Temporal Evolution Of V(t) The Averagmentioning

confidence: 99%

“…The measurement of this relaxation time is also known to be particularly challenging for dilute polymer solutions [4] for which the relaxation time is very short (micro-second or under). Previous studies [5][6][7][8] have investigated the possibility to use a cylindrical jet to measure this quantity, a method that could be suitable to probe very short times [4]. Yet, it was shown that the relaxation time obtained with this method depends on the jet operating conditions, i.e.…”

Section: Introductionmentioning

confidence: 99%

“…Yet, it was shown that the relaxation time obtained with this method depends on the jet operating conditions, i.e. the jet velocity, the amplitude and the frequency of the initial disturbance [6][7][8], thus limiting the development of this experimental method. Until recently, new results [4] suggest that an operating domain where these dependences vanish may exist.…”

mentioning

confidence: 99%

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Behaviour of free falling viscoelastic liquid jets

Tirel

Renoult

Dumouchel

et al. 2017

Proceedings ILASS–Europe 2017. 28th Conference on Liquid Atomization and Spray Systems

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In a recent work, a protocol to measure the relaxation time of dilute polymer solutions, known to be challenging, has been established [1]. This protocol is based on a 2D multi-scale description of free-falling low velocity viscoelastic liquid jets. Although the relaxation time reached an asymptotic value for high jet velocities, a significant dependence with the jet velocity is observed for low velocities. The present work reconsiders these previous experimental data using a 3D multi-scale analysis in order to identify the origin of the dependence between the relaxation time and the jet velocity. The 3D analysis demonstrates the importance of a velocity-dependent coalescence mechanism in the jet behaviour. Thanks to a simple model of jet deformation it is demonstrated that this coalescence mechanism prevents the elasto-capillary contraction of the smallest scales from occurring when the jet velocity is reduced. KeywordsDilute polymer solutions, Viscoelasticity, Jet break-up, Multi-scale analysis IntroductionContrary to Newtonian fluids, the atomisation of a cylindrical jet of a viscoelastic solution presents long life time cylindrical ligaments connecting spherical beads, the so called beads-on-a-string (BOAS) structures [2]. These structures are observed at times prior jet breakup. It is well known that the thinning evolution of the ligaments diameter is controlled by the elasticity of the liquid [3]. The decrease is exponential, with a relaxation time depending only on the physical properties of the liquid. The measurement of this relaxation time is also known to be particularly challenging for dilute polymer solutions [4] for which the relaxation time is very short (micro-second or under). Previous studies [5][6][7][8] have investigated the possibility to use a cylindrical jet to measure this quantity, a method that could be suitable to probe very short times [4]. Yet, it was shown that the relaxation time obtained with this method depends on the jet operating conditions, i.e. the jet velocity, the amplitude and the frequency of the initial disturbance [6][7][8], thus limiting the development of this experimental method. Until recently, new results [4] suggest that an operating domain where these dependences vanish may exist. In this context, a multi-scale analysis of the behaviour of free falling jets of a dilute viscoelastic solution was performed, allowing measurements of the relaxation time [1]. The dynamics of the smaller scales was monitored and an exponential decrease was observed from which a relaxation time was extracted. It was found that the measured relaxation time decreases with increasing jet velocity, reaching a plateau for sufficiently high velocities. This behaviour was related to the influence of the initial amplitude disturbance as reported in [6][7][8]. The higher jet velocity was imposed, the larger initial amplitude was observed on jet images and the lower relaxation time was measured in agreement with [6][7][8]. To date, the dependence of the relaxation time with the jet veloci...

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supporting

confidence: 56%

Section: Figure 4 Presents the Temporal Evolution Of V(t) The Averagmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Behaviour of free falling viscoelastic liquid jets

Tirel

Renoult

Dumouchel

et al. 2017

Proceedings ILASS–Europe 2017. 28th Conference on Liquid Atomization and Spray Systems

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“…Only in the case of quasi-steady elongation or elongations which have essentially the same history, can this instantaneous elongational viscosity be used for a unique characterization of the material behavior (Weinberger et al, 1974). Otherwise the instantaneous rate of stress to strain rate still represents a convenient parameter for practical comparison (Schummer et al 1983). In this study, we have developed a technique for measurement of the extensional viscosity of polymer solutions and coalwater slurries.…”

Section: Disclaimermentioning

confidence: 99%

Design of atomizers and burners for coal water slurry combustion. Quarterly report, January 1, 1996--March 31, 1996

Mansour¹,

Chigier²

1996

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ABSTRACT6-A novel extensional rheotester was developed to measure the extensional properties of aqueous solutions of Polyacrilamide E10 and coal water slurries (CWS). When a drop of viscoelastic liquid or CWS containing additives is allowed to form at the end of a capillary tube, it starts to fall once its weight exceeds the retaining force exerted by surface tension. In experiments with aqueous solutions of Polyacrilamide it was observed that a long filament of fluid connected the droplet to the end of the capillary tube. The filament partially supported the droplet slowing its rate of fall. In order to evaluate the transient elongational stresses and elongational viscosity that are developed in the long threads of liquid before breakup, the mass (m), the diameter (D), the velocity (V) and the acceleration (a) of the suspended droplet along with the diameter of the filament (d) are measured. The length of the trailing filament is also measured as a function of time in order to determine the filament stretch rate (i). The time dependent behavior of the filament diameter was also measured using a laser attenuation technique. The strain rate of the filament was determined from the experimental values of i /~ and -2 i d , where the dot refers to differentiation with respect to time.Seven different aqueous solutions of Polyacrilamide E10 were prepared spanning a wide range of polymer concentration (0.5%, 0.25%, 0.125%, 0.0625%, 0.03 125 %, 0.015625 %, 0.0078125%). The data gave a single relaxation time for each solution. This relaxation time for uniaxial extension is found to increase with El0 concentration.

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Rheological Properties Influence Tackiness, Application and Performance of Nail Polish/Lacquer Formulations

Jimenez

Narváez

et al. 2021

Surface Science and Adhesion in Cosmetics

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A new elongational rheometer for polymer solutions

Cited by 85 publications

References 10 publications

Behaviour of free falling viscoelastic liquid jets

Behaviour of free falling viscoelastic liquid jets

Design of atomizers and burners for coal water slurry combustion. Quarterly report, January 1, 1996--March 31, 1996

Rheological Properties Influence Tackiness, Application and Performance of Nail Polish/Lacquer Formulations

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