Marangoni-effect velocity distribution due to time-oscillatory temperature gradients in zero-gravity environment

Fundamental physics are studied on the movement of droplets for sizes ranging from 0.1 μl to 1.0 μl on a solid surface subjected to temperature gradients using numerical computations and the comparison with experiments. The receding/advancing contact angles relating to the droplet size and shape are the key parameters of droplet moving and the differences subjected to the temperature gradients induce unbalanced recirculation zones inside the moving droplet, thus induces driving force to drag the droplet. It is found that droplet of smaller size moves faster with smoothly changing speed and the droplet of larger size moves with fluctuating speed and the average moving speed is roughly the same magnitude as that with two-dimensional heating.

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The Effect of the Marangoni Flow on the Film Condensation

ASME 2009 Second International Conference on Micro/Nanoscale Heat and Mass Transfer, Volume 2 ◽

10.1115/mnhmt2009-18020 ◽

2009 ◽

Author(s):

Baohong Peng ◽

Li Yang ◽

Juan Wen

Keyword(s):

Surface Tension ◽

Reynolds Number ◽

Marangoni Effect ◽

Film Condensation ◽

Zero Gravity ◽

Vapor Film ◽

Marangoni Flow ◽

Shearing Force ◽

Gravity Condition ◽

Average Ratio

The objective of this paper is to quantify the effect of Marangoni flow on the vapor film condensation and analyzed the effect of the gravity, the shearing force at the gas-liquid interface and the Marangoni strength caused by the surface tension on the Nusselt number. The results show that the effect of the gravity is very clear to the thickness of the film. Marangoni effect can not be ignored at zero gravity condition. The effect of the vapor Reynolds number (Rev0) at the zero-gravity conditions on the film is bigger than that at the gravity conditions. The average ratio of the film thickness (δ¯) is 6.5% at the gravity conditions and 21.5% at zero-gravity conditions when the Rev0 changes from 8000 to 15000.

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Mimicking wettability alterations using temperature gradients for water nanodroplets

Nanoscale ◽

10.1039/c7nr03320f ◽

2017 ◽

Vol 9 (34) ◽

pp. 12509-12515 ◽

Cited By ~ 11

Author(s):

Chirodeep Bakli ◽

Sree Hari P. D. ◽

Suman Chakraborty

Keyword(s):

Water Droplet ◽

Marangoni Effect ◽

Temperature Gradients ◽

Hydrophobic Substrate

A sessile water droplet moves from colder to warmer regions on a hydrophobic substrate, guided by the coupled effects of wettability and evaporation, demonstrating ‘reverse-Marangoni effect’.

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Dynamics of comets in the collapsing protosolar nebula

International Astronomical Union Colloquium ◽

10.1017/s0252921100031225 ◽

1999 ◽

Vol 173 ◽

pp. 45-50

Author(s):

L. Neslušan

Keyword(s):

Solar System ◽

Velocity Distribution ◽

Oort Cloud ◽

Interstellar Clouds ◽

Protosolar Nebula ◽

Moving Bodies

AbstractComets are created in the cool, dense regions of interstellar clouds. These macroscopic bodies take place in the collapse of protostar cloud as mechanically moving bodies in contrast to the gas and miscroscopic dust holding the laws of hydrodynamics. In the presented contribution, there is given an evidence concerning the Solar system comets: if the velocity distribution of comets before the collapse was similar to that in the Oort cloud at the present, then the comets remained at large cloud-centric distances. Hence, the comets in the solar Oort cloud represent a relict of the nebular stage of the Solar system.

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