Effects of incompressible surfactant on thermocapillary interactions of spherical drops

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Collision efficiencies are determined for two surfactant-covered spherical drops in the limit of nearly uniform surface coverage in thermocapillary motion. The problem is linearized by assuming dilute surfactant concentration, with the effect of surfactant controlled by a single retardation parameter A. The mobility function LA along the drops' line of centers is much less than zero over a wide range of parameters, so that the smaller drop can move faster than the larger one at moderate to large separations. At surface Péclet numbers less than 10, the incompressible surfactant model agrees well with solution of the full convective-diffusion equation for the minimum separation between drops. With the exception of non-conducting drops, the collision efficiencies become zero at moderate values of A. A model system of contaminated ethyl salicylate (ES) drops in diethylene glycol (DEG) is studied in thermocapillary motion. Population dynamics simulations confirm the coalescence-inhibiting effect of incompressible surfactant on the evolution of the ES/DEG drop-size distribution.

Original languageEnglish (US)
Pages (from-to)417-426
Number of pages10
JournalInternational Journal of Multiphase Flow
Volume35
Issue number5
DOIs
StatePublished - May 1 2009

Fingerprint

Surface-Active Agents
Surface active agents
surfactants
salicylates
Glycols
interactions
glycols
drop size
Population dynamics
collisions
Coalescence
coalescing
Computer simulation
simulation
ethyl salicylate
diethylene glycol

Keywords

  • Bubbles
  • Drops
  • Surfactant
  • Thermocapillary

Cite this

Effects of incompressible surfactant on thermocapillary interactions of spherical drops. / Rother, Michael A.

In: International Journal of Multiphase Flow, Vol. 35, No. 5, 01.05.2009, p. 417-426.

Research output: Contribution to journalArticle

@article{fd46431dc0f24a808982ed0d6a1d6d1c,
title = "Effects of incompressible surfactant on thermocapillary interactions of spherical drops",
abstract = "Collision efficiencies are determined for two surfactant-covered spherical drops in the limit of nearly uniform surface coverage in thermocapillary motion. The problem is linearized by assuming dilute surfactant concentration, with the effect of surfactant controlled by a single retardation parameter A. The mobility function LA along the drops' line of centers is much less than zero over a wide range of parameters, so that the smaller drop can move faster than the larger one at moderate to large separations. At surface P{\'e}clet numbers less than 10, the incompressible surfactant model agrees well with solution of the full convective-diffusion equation for the minimum separation between drops. With the exception of non-conducting drops, the collision efficiencies become zero at moderate values of A. A model system of contaminated ethyl salicylate (ES) drops in diethylene glycol (DEG) is studied in thermocapillary motion. Population dynamics simulations confirm the coalescence-inhibiting effect of incompressible surfactant on the evolution of the ES/DEG drop-size distribution.",
keywords = "Bubbles, Drops, Surfactant, Thermocapillary",
author = "Rother, {Michael A}",
year = "2009",
month = "5",
day = "1",
doi = "10.1016/j.ijmultiphaseflow.2009.02.005",
language = "English (US)",
volume = "35",
pages = "417--426",
journal = "International Journal of Multiphase Flow",
issn = "0301-9322",
publisher = "Elsevier BV",
number = "5",

}

TY - JOUR

T1 - Effects of incompressible surfactant on thermocapillary interactions of spherical drops

AU - Rother, Michael A

PY - 2009/5/1

Y1 - 2009/5/1

N2 - Collision efficiencies are determined for two surfactant-covered spherical drops in the limit of nearly uniform surface coverage in thermocapillary motion. The problem is linearized by assuming dilute surfactant concentration, with the effect of surfactant controlled by a single retardation parameter A. The mobility function LA along the drops' line of centers is much less than zero over a wide range of parameters, so that the smaller drop can move faster than the larger one at moderate to large separations. At surface Péclet numbers less than 10, the incompressible surfactant model agrees well with solution of the full convective-diffusion equation for the minimum separation between drops. With the exception of non-conducting drops, the collision efficiencies become zero at moderate values of A. A model system of contaminated ethyl salicylate (ES) drops in diethylene glycol (DEG) is studied in thermocapillary motion. Population dynamics simulations confirm the coalescence-inhibiting effect of incompressible surfactant on the evolution of the ES/DEG drop-size distribution.

AB - Collision efficiencies are determined for two surfactant-covered spherical drops in the limit of nearly uniform surface coverage in thermocapillary motion. The problem is linearized by assuming dilute surfactant concentration, with the effect of surfactant controlled by a single retardation parameter A. The mobility function LA along the drops' line of centers is much less than zero over a wide range of parameters, so that the smaller drop can move faster than the larger one at moderate to large separations. At surface Péclet numbers less than 10, the incompressible surfactant model agrees well with solution of the full convective-diffusion equation for the minimum separation between drops. With the exception of non-conducting drops, the collision efficiencies become zero at moderate values of A. A model system of contaminated ethyl salicylate (ES) drops in diethylene glycol (DEG) is studied in thermocapillary motion. Population dynamics simulations confirm the coalescence-inhibiting effect of incompressible surfactant on the evolution of the ES/DEG drop-size distribution.

KW - Bubbles

KW - Drops

KW - Surfactant

KW - Thermocapillary

UR - http://www.scopus.com/inward/record.url?scp=62849103582&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=62849103582&partnerID=8YFLogxK

U2 - 10.1016/j.ijmultiphaseflow.2009.02.005

DO - 10.1016/j.ijmultiphaseflow.2009.02.005

M3 - Article

AN - SCOPUS:62849103582

VL - 35

SP - 417

EP - 426

JO - International Journal of Multiphase Flow

JF - International Journal of Multiphase Flow

SN - 0301-9322

IS - 5

ER -