Evaporation-induced Benard convection -- A new type and its mechanism

Conference · Tue Jul 01 04:00:00 EDT 1997

OSTI ID:20014422

Yang, W J; Zhang, N; Chai, A; Guo, K H; Sakamoto, Masahiko

Both the buoyancy-induced (Rayleigh-Bernard) and surface tension-induced (Marangoni-Benard) convection require a negative temperature gradient to occur in a thin liquid layer, either heated from below or cooled from above. This study has revealed an entirely different way of bringing about cellular convection in a thin liquid layer with evaporation at the free surface and cooled, adiabatic or heated from below. Temperature-time history is monitored in the liquid layer and its adjacent atmospheric environment. Flow visualization is conducted by means of the tracer method and results are compared with those obtained in the existing literature using an optical technique. Various different liquids are tested including those classified as stable, unstable, unstable types in the study of convection phenomena in a sessile droplet evaporating on a plate. It is disclosed from the study that evaporation at the free surface of a thin liquid layer results in a negative temperature gradient in the upper stratum in which cellular convection may occur irrespective of a positive, zero, or negative temperature gradient prevailing in the remaining lower stratum.

• Research Organization: Univ. of Michigan, Ann Arbor, MI (US)
• OSTI ID: 20014422
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
CONVECTION
EVAPORATION
EXPERIMENTAL DATA
FLOW VISUALIZATION
LIQUIDS
TEMPERATURE GRADIENTS
THIN FILMS