Elongational flow behavior of viscoelastic liquids: Part I. Modeling of bubble collapse

AIChE Journal ◽  
1977 ◽  
Vol 23 (5) ◽  
pp. 714-722 ◽  
Author(s):  
Glen Pearson ◽  
Stanley Middleman
Keyword(s):  
Flow Behavior ◽  
Elongational Flow ◽  
Bubble Collapse ◽  
Viscoelastic Liquids

Simulation of bubble growth and collapse in linear and pom-pom polymers

e-Polymers ◽  
2002 ◽  
Vol 2 (1) ◽  
Author(s):  
Uday S. Agarwal
Keyword(s):  
Bubble Growth ◽  
Bubble Dynamics ◽  
Polymer Melt ◽  
Integral Form ◽  
Polymer Chains ◽  
Bubble Collapse ◽  
Flow Strength ◽  
Branch Lengths ◽  
Programming Effort ◽  
Viscoelastic Liquids

AbstractExisting approaches to simulate the bubble growth/collapse in viscoelastic liquids use the integral form of a constitutive equation, that can additionally be analytically integrated over the radial domain. Here we represent the process by a system of simultaneous partial differential equations, with fixed and finite boundaries. This enables a direct computer implementation with commercially available software, with little additional programming effort. The involved co-ordinate transformation preferably does not correspond to the material co-ordinates. The surrounding liquid can be simulated as being a finite film or of infinite extent, with simply a change in one computational parameter. We simulate hydrodynamically induced bubble dynamics in viscolelastic liquids, and estimate the flow strength (elongational strain rate) and its possible role in flow induced scission of polymer chains in liquids experiencing bubble collapse. Calculations are also performed to evaluate the influence of backbone and branch lengths when the surrounding fluid is a branched polymer melt, using the pom-pom model to describe the rheological behavior.

Shear and elongational flow behavior of acrylic thickener solutions. Part II: effect of gel content

2008 ◽  
Vol 48 (4) ◽  
pp. 397-407 ◽  
Author(s):  
Saeid Kheirandish ◽  
Ilshat Gubaydullin ◽  
Norbert Willenbacher
Keyword(s):  
Flow Behavior ◽  
Elongational Flow ◽  
Gel Content

Scaling Behavior in Electrohydrodynamic Jetting of Polymeric Solutions

2019 ◽  
Author(s):  
Abhishek K. Singh ◽  
Kaushlendra Dubey ◽  
Rajiv K. Srivastava ◽  
Supreet Singh Bahga
Keyword(s):  
Flow Rate ◽  
Flow Behavior ◽  
Polymer Concentration ◽  
Viscoelastic Behavior ◽  
Scaling Behavior ◽  
Jet Stability ◽  
Polymeric Solutions ◽  
Newtonian Liquids ◽  
The Stability ◽  
Viscoelastic Liquids

Abstract An electrohydrodynamic (EHD) jet forms when a leaky-dielectric liquid issuing out of a needle is accelerated and stretched by electrostatic forces. Stability and scaling behavior of the EHD jet of polymeric solutions depend on electrostatics, fluid mechanics and rheology of the liquid. While EHD jetting of Newtonian liquids have been described in the literature, the effect of non-Newtonian rheology on EHD jetting is still not well-understood. Therefore, we present a detailed experimental investigation of the stability and scaling behavior of EHD jets of polymeric solutions that exhibit non-Newtonian flow behavior. The stability of cone-jet was analyzed by varying flow rate, electric field and polymer concentration. Experiments were performed for polymeric solutions of polycaprolactone (PCL) dissolved in acetic acid. Our experiments show that non-Newtonian viscoelastic behavior can significantly alter the stability characteristics of the EHD jet. We have found that increase of elasticity of polymeric solutions results in enhanced jet stability. Finally, we present the dependence of experimentally measured diameter dj of the EHD jet on the flow rate Q. Experimentally measured diameter of the EHD jet scales as dj ∼ Q0.65 for both Newtonian and non-Newtonian viscoelastic liquids, which can be attributed to dominant inertia forces in our experiment.

A Data Acquisition System to Detect Bubble Collapse Time and Pressure Losses in Water Cavitation

2013 ◽  
pp. 39-56
Author(s):  
M. G. De Giorgi ◽  
A. Ficarella ◽  
M. Tarantino
Keyword(s):  
Data Acquisition ◽  
Flow Behavior ◽  
Pressure Fluctuations ◽  
Data Acquisition System ◽  
Acquisition System ◽  
Bubble Collapse ◽  
Pressure Losses ◽  
Collapse Time ◽  
Frequency Components ◽  
Visual Observations

This paper presents a data acquisition system oriented to detect bubble collapse time and pressure losses in water cavitation in an internal orifice. An experimental campaign on a cavitating flow of water through an orifice has been performed to analyze the flow behavior at different pressures and temperatures. The experiments were based on visual observations and pressure fluctuations frequency analysis. Comparing the visual observations and the spectral analysis of the pressure signals, it is evident that the behavior of the different cavitating flows can be correlated to the frequency spectrum of the upstream, downstream and differential pressure fluctuations. The further reduction of the cavitation number and the consequent increase in the width of the cavitating area are related to a corresponding significant increase of the amplitude of typical frequency components. The spectrogram analysis of the pressure signals leads to the evaluation of the bubble collapse time, also compared with the numerical results calculated by the Rayleigh–Plesset equation.

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