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Title: Bag breakup of low viscosity drops in the presence of a continuous air jet

Abstract

This work examines the breakup of a single drop of various low viscosity fluids as it deforms in the presence of continuous horizontal air jet. Such a fragmentation typically occurs after the bulk liquid has disintegrated upon exiting the atomizer and is in the form of an ensemble of drops which undergo further breakup. The drop deformation and its eventual disintegration is important in evaluating the efficacy of a particular industrial process, be it combustion in automobile engines or pesticide spraying in agricultural applications. The interplay between competing influences of surface tension and aerodynamic disruptive forces is represented by the Weber number, We, and Ohnesorge number, Oh, and used to describe the breakup morphology. The breakup pattern considered in our study corresponds to that of a bag attached to a toroidal ring which occurs from ∼12 < We < ∼16. We aim to address several issues connected with this breakup process and their dependence on We and Oh which have been hitherto unexplored. The We boundary at which breakup begins is theoretically determined and the expression obtained, We=12(1+2/3Oh{sup 2}), is found to match well with experimental data ([L.-P. Hsiang and G. M. Faeth, Int. J. Multiphase Flow 21(4), 545–560 (1995)]more » and [R. S. Brodkey, “Formation of drops and bubbles,” in The Phenomena of Fluid Motions (Addison-Wesley, Reading, 1967)]). An exponential growth in the radial extent of the deformed drop and the streamline dimension of the bag is predicted by a theoretical model and confirmed by experimental findings. These quantities are observed to strongly depend on We. However, their dependence on Oh is weak.« less

Authors:
;  [1]
  1. Maurice J. Zucrow Laboratories, Purdue University, West Lafayette, Indiana 47906 (United States)
Publication Date:
OSTI Identifier:
22311233
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Fluids (1994); Journal Volume: 26; Journal Issue: 7; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; AIR; BUBBLES; COMBUSTION; DEFORMATION; ENGINES; FRAGMENTATION; JETS; LIQUIDS; MORPHOLOGY; MULTIPHASE FLOW; PESTICIDES; SURFACE TENSION; VISCOSITY

Citation Formats

Kulkarni, V., E-mail: vkulkarn@purdue.edu, and Sojka, P. E. Bag breakup of low viscosity drops in the presence of a continuous air jet. United States: N. p., 2014. Web. doi:10.1063/1.4887817.
Kulkarni, V., E-mail: vkulkarn@purdue.edu, & Sojka, P. E. Bag breakup of low viscosity drops in the presence of a continuous air jet. United States. doi:10.1063/1.4887817.
Kulkarni, V., E-mail: vkulkarn@purdue.edu, and Sojka, P. E. Tue . "Bag breakup of low viscosity drops in the presence of a continuous air jet". United States. doi:10.1063/1.4887817.
@article{osti_22311233,
title = {Bag breakup of low viscosity drops in the presence of a continuous air jet},
author = {Kulkarni, V., E-mail: vkulkarn@purdue.edu and Sojka, P. E.},
abstractNote = {This work examines the breakup of a single drop of various low viscosity fluids as it deforms in the presence of continuous horizontal air jet. Such a fragmentation typically occurs after the bulk liquid has disintegrated upon exiting the atomizer and is in the form of an ensemble of drops which undergo further breakup. The drop deformation and its eventual disintegration is important in evaluating the efficacy of a particular industrial process, be it combustion in automobile engines or pesticide spraying in agricultural applications. The interplay between competing influences of surface tension and aerodynamic disruptive forces is represented by the Weber number, We, and Ohnesorge number, Oh, and used to describe the breakup morphology. The breakup pattern considered in our study corresponds to that of a bag attached to a toroidal ring which occurs from ∼12 < We < ∼16. We aim to address several issues connected with this breakup process and their dependence on We and Oh which have been hitherto unexplored. The We boundary at which breakup begins is theoretically determined and the expression obtained, We=12(1+2/3Oh{sup 2}), is found to match well with experimental data ([L.-P. Hsiang and G. M. Faeth, Int. J. Multiphase Flow 21(4), 545–560 (1995)] and [R. S. Brodkey, “Formation of drops and bubbles,” in The Phenomena of Fluid Motions (Addison-Wesley, Reading, 1967)]). An exponential growth in the radial extent of the deformed drop and the streamline dimension of the bag is predicted by a theoretical model and confirmed by experimental findings. These quantities are observed to strongly depend on We. However, their dependence on Oh is weak.},
doi = {10.1063/1.4887817},
journal = {Physics of Fluids (1994)},
number = 7,
volume = 26,
place = {United States},
year = {Tue Jul 15 00:00:00 EDT 2014},
month = {Tue Jul 15 00:00:00 EDT 2014}
}
  • This paper presents a numerical study of the dynamics of a viscous liquid drop that is being formed directly at the tip of a vertical tube into ambient air. A model is developed to predict the evolution of the drop shape and its breakup based on RIPPLE, which is a solution algorithm for computing transient, two-dimensional, incompressible fluid flow with surface tension on free surfaces of general topology. The full Navier-Stokes system is solved by using finite-difference formulation on a Eulerian mesh. The mesh is fixed in space, with the flow and surface moving through it to ensure accurate calculationsmore » of complex free surface flows and topology, including surface breakup and coalescence. The novel feature of the numerical algorithm is the use of a Eulerian volume-tracking approach which allows the calculations to pass the breaking point during formation of a drop continuously without interruption or numerical modification and, therefore, to explore the features of generation of satellite droplets. The effects of physical and geometric parameters on the nonlinear dynamics of drop growth and breakup are investigated. The focus here is on drop breakup and subsequent formation of satellite droplets. The effects of finite inertial, capillary, viscous, and gravitational forces are all accounted for to classify different formation dynamics and to elucidate features of satellite droplet generation. The numerical predictions are compared with experimental measurements for water drops, and the results show good agreement.« less
  • No abstract prepared.
  • The influence of the breakup and evaporation of drops on flows of two-phase mixtures of a gas containing liquid drops is investigated. The laws governing the interactions of the phases in the presence of drop breakup (by the surface layer stripping mechanism) are specific. Certain characteristics of the numerical algorithm are discussed. The influence of the main governing parameters on the transverse flow of gas-drop flows around a flat plate is investigated. {copyright} 1989 Plenum Publishing Corporation