Force on a small spherical evaporating particle in its pure vapour due to motion and temperature gradients
✍ Scribed by G.C. Gardner
- Publisher
- Elsevier Science
- Year
- 1968
- Tongue
- English
- Weight
- 916 KB
- Volume
- 23
- Category
- Article
- ISSN
- 0009-2509
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✦ Synopsis
Analyses are made for the free molecular regime, where the particle is small compared to the mean free path of vapour molecules, and for the viscous continuum-slip regime, where the particle is large compared to the mean free path.
Energy exchange between the vapour and the particle is considered in the free molecular regime as well as the momentum exchange, which has previously been considered for inert, non-evaporating particles. Thus it is shown that conduction of heat within the particle can have a small importance for the larger particles that are included within the regime. Otherwise the equations for the force on a particle reduce to particular forms of those already derived for inert particles.
The equations for the continuum regime, without slip, shows that the particle has an equilibrium velocity equal to the velocity that the continuum would attain, if the heat being conducted far from the particle, due to the temperature gradient, was used to evaporate more vapour and thus create a vanour flow. When, however, the oarticle size becomes small enough for slip to be important, the equilibrium velocity rises above this value.