Thermophoresis of liquid airborne particles in gravity at continuum regime
Journal
Aerosol Science and Technology
Journal Volume
37
Journal Issue
6
Date Issued
2003
Author(s)
Yang C.Y.
Abstract
An analytical study is presented for the thermophoretic motion of an aerosol droplet in a prescribed temperature gradient under the influence of gravity.The Peclet and Reynolds numbers are assumed small, so that the temperature distributions are governed by the Laplace equation and the flow fields are governed by the Stokes equation.The temperature discontinuity, thermal creep, and hydrodynamic slip features that occurred at the droplet surface are considered.The slow motion of a liquid aerosol sphere subject to the combination of thermophoresis and sedimentation is obtained by superposition of the individual solutions for pure thermophoresis and pure body-force-driven motion, since both the governing equations and boundary conditions in this problem are linear.The stream functions of the internal and external flows, which are displayed in both the laboratory frame and a reference frame moving with the droplet, as well as the migrating velocity of a droplet, are formulated generally.The flow structures manifest more remarkable topologies than do those of common intuition developed from sedimentation.Our results can be simplified to the corresponding motion for solid aerosol particles.
SDGs
Type
journal article