Numerical Simulation of the Effect of Free Surface Shape on Marangoni Convection in a Liquid Film Sustained in a Circular Ring with Different Prandtl Numbers

Int. J. Microgravity Sci. Appl. 2016p330309
Nikhil ADKAR, Takuya YAMAMOTO, Youhei TAKAGI, Yasunori OKANO and Sadik DOST
Department of Materials Engineering Science, Osaka University,Crystal Growth Laboratory, University of Victoria
In 2003 NASA astronaut Dr. D. Pettit conducted thermocapillary experiments in a thin water film (Prandtl number; Pr = 7) sustained in a circular ring onboard the International Space Station (ISS). When a section of the ring was heated, a thermocapillary flow developed from the cold region towards the hotter region. This unusual flow phenomenon (being from cold to hot) was explained by the dependency of free surface shape on the flow pattern observed in the film. However, the dependency of flow behavior on the Prandtl number was not investigated previously. Motivated by the wide range of applications of the low-Prandtl-number liquids, numerical simulations for the flow phenomena observed in the films of different shapes and Prandtl numbers were performed under zero gravity. Results have shown that in the case of low-Prandtl-number film although the flow direction remained the same, the flow velocity increased significantly. This interesting phenomenon is explained by means of the temperature gradient in the film in the y- (vertical) and θ- (circumferential) directions.
Thermocapillary flow, Computational fluid dynamics, Low Prandtl number, Marangoni convection

Received 18 September 2015, accepted 19 May 2016, published 31 July 2016.

© The Japan Society of Microgravity Applicaiton

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