Transient stefan flow and thermophoresis around an evaporating droplet

Mechanism of Stefan Flow in the Collection of Particles on Evaporating/Condensing Surfaces: A Review

“…However, the phase change process at the initial moment is actually unsteady. At the condensing surface, a strong transient stream of water molecules occurs at the initial moment, 17,80 which is not described in the theoretical calculation. The time of the unsteady process is much shorter than the action time of phoretic force during the residence time of particles in the vicinity of the droplet.…”

“…This result indicates the effect of Stefan flow on the particles that appears earlier or stronger than that of thermophoresis in the early stage of evaporation. Vittori found that Stefan flow reached its maximum value at the initial moment of evaporation by obtaining the analytical solution of heat and mass transfer during transient cooling of the evaporating droplet. The thermophoretic velocity at the beginning of evaporation for tens of micrometers of evaporating droplets was 2 orders of magnitude smaller than the Stefan flow.…”

“…Studies found that Stefan flow can control the movement of particles near the phase interface. 16,17 According to the literature on particle collection, previous studies show that researchers have an insufficient understanding of the significance of Stefan flow, even misunderstandings are observed. Therefore, Stefan flow theory in the field of particle collection is comprehensively discussed and analyzed in this study.…”

Jožef Stefan, master of transport phenomena

“…In clouds, this represents the flow of water vapour towards growing water droplets, carrying with it aerosol particles, thereby cleansing the surrounding air. Of course, the situation in a cloud is complicated by geometry and heat released at condensation [11].…”

The Stefan outflow in a multicomponent vapor–gas atmosphere around a droplet and its role for cloud expansion

“…However there are some atmospheric situations where the Stefan flow may be important. The particle scavenging efficiency of vapor-grown ice crystals falling from mixed clouds proves to be very high due to the Stefan flow which pushes airborne particles away from the surface of the supercooled droplets evaporating in the vicinity of an ice crystal ( 20 ). The influence of the Stefan flow on the heat balance of a char particle should be taken into account in oxy-fuel combustion (temperature ≈ 1400 K), because, the presence of Stefan's flow greatly weakens the heat transfer by conduction and accelerates the heat loss from the particle, which makes the particle temperature lower ( 21 ).…”