0
Research Papers

Numerical Simulation of Formation and Distortion of Taylor Cones

[+] Author and Article Information
Kamal Sarkar

e-mail: ksarkar@utpa.edu

Alberto Urias

Mechanical Engineering Department,
The University of Texas—Pan American,
Edinburg, TX 78541

1Corresponding author.

Manuscript received April 16, 2012; final manuscript received August 26, 2012; published online March 26, 2013. Assoc. Editor: Debjyoti Banerjee.

J. Nanotechnol. Eng. Med 3(4), 041001 (Mar 26, 2013) (10 pages) doi:10.1115/1.4023243 History: Received April 16, 2012; Revised August 26, 2012

Taylor cones are integral parts in many important applications like electrospinning and electrospray mass spectroscopy. A better understanding of this complex phenomenon of Taylor cone is critical for better control of these processes. As an example, if it is possible to identify and prioritize the roles of fluid characteristics and externally applied electric field, it might be easier to target and control the diameters of nanofibers in an electrospinning process. Under the influence of high electric fields, Taylor cones are formed by a number of liquids including many polymeric solutions. Because of small spatial (microns and below) and temporal (microseconds and below) scales, it is difficult to experimentally study the transient formation of Taylor cones. A number of theoretical analyses have been done under simplifying assumptions like uniform electric field, constant electrohydrodynamic behaviors of the fluid, stationary droplet, etc. Initial Taylor formulation included the introduction of “leaky dielectric” that accumulated charges only on the surface for certain dielectric fluids. Yarin et al. later developed analysis for stationary droplets assuming them to be “perfectly conducting”. To simulate the electrospinning process, the formulation needs the ability to analyze moving boundary conditions, complex fluid properties, three dimensional geometry, and nonlinear coupling between air and liquid, among others. To overcome some of the assumptions of theoretical analyses and as another complementary tool, a computer simulation method was proposed using a commercially available software. In this investigation, much studied aqueous polyethylene oxide (PEO) solution was used to study formation and distortion of Taylor cones. An initial velocity was given to the fluid from the tip of a nozzle and an appropriate electric field was applied to form the Taylor cones. Literature values were used for flow, fluid, and electrical characteristics of the solution. By appropriately manipulating fluid velocities and electric fields, simulations were successful to both replicate the classical cone and distort it to various degrees. These formation and distortion of Taylor cones were similar to reported experimental results. While the numerical and experimental Taylor cones were significantly different in sizes, nondimensional shapes, and sizes of both the results were strikingly similar. Velocities of the fluid in the jet jumped almost 50 times to meters/second as was experimentally observed. Unlike theoretical solutions, the simulation results showed the interaction of the electric fields between the air and advancing fluid tip.

FIGURES IN THIS ARTICLE
<>
Copyright © 2013 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

Schematic of electrospinning process

Grahic Jump Location
Fig. 2

Sketch of near field electrospinning [22]

Grahic Jump Location
Fig. 3

Axisymmetric model for Taylor cone

Grahic Jump Location
Fig. 4

Finite volume mesh model

Grahic Jump Location
Fig. 5

Fluid fronts at various time steps (time in nanoseconds)

Grahic Jump Location
Fig. 6

Electric field (V/μm) magnitude at various time (nanosecond) steps

Grahic Jump Location
Fig. 7

Velocity (μm/s) in axial (Y) direction at various (nanosecond) time steps

Grahic Jump Location
Fig. 8

Velocity vectors (a), (c), and (d) and stream lines (b) in the Taylor cone at various time steps (in nanoseconds). Time steps are (a) 250, (b) 2000, (c) 100, and (d) 250 μs.

Grahic Jump Location
Fig. 9

Comparison of experimental and simulation results of electrospinning (please refer Table 3 for process parameters)

Grahic Jump Location
Fig. 10

Comparison of simulated and experimental jets in normalized scale

Grahic Jump Location
Fig. 11

Comparison of simulated and experimental results in normalized scales

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In