Hostname: page-component-586b7cd67f-vdxz6 Total loading time: 0 Render date: 2024-11-27T05:28:54.207Z Has data issue: false hasContentIssue false

Inside rod induced horizontal capillary emptying

Published online by Cambridge University Press:  11 August 2021

Xinping Zhou*
Affiliation:
School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan430074, PR China
Gang Zhang
Affiliation:
School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan430074, PR China Department of Mechanics, Huazhong University of Science and Technology, Wuhan430074, PR China
Chengwei Zhu
Affiliation:
School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan430074, PR China Department of Mechanics, Huazhong University of Science and Technology, Wuhan430074, PR China
Dongwen Tan
Affiliation:
School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan430074, PR China
Chenyu Fu
Affiliation:
School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan430074, PR China
*
 Email address for correspondence: [email protected]

Abstract

The removal of a liquid blockage from a tube is of importance in many processes. If the Bond number (which measures the relative size of the gravitational force by comparison with the surface tension force on the blockage plug) is large enough, then the tube will become non-occluding automatically. If not, then other measures are required to remove the blockage and the insertion of a rod is one such measure. We investigate this situation in a horizontal capillary in a downward gravity field. Theoretical results are obtained and compared with experiments. We observe that a rod insertion can cause a change from liquid plug to non-occlusion in a horizontal capillary. For uniform inner and outer contact angles, compared with the case without an inside rod, the maximum of the critical emptying line decreases significantly, but the minimum decreases a little only for a large enough value of the ratio of inner radius to outer radius (χ). We find that changing the contact angles of the inserted tube can significantly affect the non-occluding of the tube. The minimum of critical emptying line can be lowered clearly, and the minimum for a large enough value of χ is much lower than that reached for a circular tube. The insertion of a hydrophobic (hydrophilic) rod with a large enough radius can make the liquid emptying easier in a horizontal hydrophilic (hydrophobic) capillary. This provides an effective method of triggering drainage of a fluid from a capillary in applications such as optofluidics and microfluidics.

Type
JFM Papers
Copyright
© The Author(s), 2021. Published by Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Bhatnagar, R. & Finn, R. 2016 On the capillarity equation in two dimensions. J. Math. Fluid Mech. 18, 731738.CrossRefGoogle Scholar
Brakke, K.A. 1992 The surface evolver. Exp. Maths 1, 141165.CrossRefGoogle Scholar
Chen, Y. & Collicott, S.H. 2006 Study of wetting in an asymmetrical vane-wall gap in propellant tanks. AIAA J. 44, 859867.CrossRefGoogle Scholar
Concus, P. & Finn, R. 1969 On the behavior of a capillary surface in a wedge. Proc. Natl Acad. Sci. USA 63, 292299.CrossRefGoogle Scholar
Finn, R. 1986 Equilibrium Capillary Surfaces. Springer-Verlag.CrossRefGoogle Scholar
Kang, C. & Mutabazi, I. 2021 Columnar vortices induced by dielectrophoretic force in a stationary cylindrical annulus filled with a dielectric liquid. J. Fluid Mech. 908, A26.CrossRefGoogle Scholar
Lee, C.C., Wu, A. & Li, M. 2020 Venous air embolism during neurosurgery. In Essentials of Neurosurgical Anesthesia & Critical Care: Strategies for Prevention, Early Detection, and Successful Management of Perioperative Complications, pp. 287–291. Springer International Publishing.CrossRefGoogle Scholar
Manning, R.E. & Collicott, S.H. 2015 Existence of static capillary plugs in horizontal rectangular cylinders. Microfluid Nanofluid 19, 11591168.CrossRefGoogle Scholar
Manning, R., Collicott, S. & Finn, R. 2011 Occlusion criteria in tubes under transverse body forces. J. Fluid Mech. 682, 397414.CrossRefGoogle Scholar
Parry, A.O., Rascón, C., Jamie, E.A.G. & Aarts, D.G.A.L. 2012 Capillary emptying and shortrange wetting. Phys. Rev. Lett. 108 (24), 246101.CrossRefGoogle Scholar
Pour, N.B. & Thiessen, D.B. 2019 Equilibrium configurations of drops or bubbles in an eccentric annulus. J. Fluid Mech. 863, 364385.CrossRefGoogle Scholar
Rascón, C., Parry, A.O. & Aarts, D.G.A.L. 2016 Geometry-induced capillary emptying. Proc. Natl Acad. Sci. USA 113, 1263312636.CrossRefGoogle ScholarPubMed
Smedley, G. 1990 Containments for liquids at zero gravity. Microgravity Sci. Technol. 3, 1323.Google Scholar
Stokes, Y.M. 2021 A two-dimensional asymptotic model for capillary collapse. J. Fluid Mech. 909, A5.CrossRefGoogle Scholar
Verma, G., Saraj, C.S., Yadav, G., Singh, S.C. & Guo, C. 2020 Generalized emptying criteria for finite-lengthed capillary. Phys. Rev. Fluids 5, 112201(R).CrossRefGoogle Scholar
Zhang, F.Y., Yang, X.G. & Wang, C.Y. 2006 Liquid water removal from a polymer electrolyte fuel cell. J. Electrochem. Soc. 153, A225A232.CrossRefGoogle Scholar
Zhou, X. & Zhang, F. 2017 Bifurcation of a partially immersed plate between two parallel plates. J. Fluid Mech. 817, 122137.CrossRefGoogle Scholar
Zhu, C., Zhou, X. & Zhang, G. 2020 Capillary plugs in horizontal rectangular tubes with non-uniform contact angles. J. Fluid Mech. 901, R1.CrossRefGoogle Scholar