Library Subscription: Guest
Home Archives Thermal Letter Officers Future meetings Assembly for International Heat Transfer Conferences
International Heat Transfer Conference 16

ISSN: 2377-424X (online)
ISSN: 2377-4371 (flashdrive)

INFLUENCE OF SUBSTRATE TEMPERATURE ON MARANGONI CONVECTION INSTABILITY IN AN EVAPORATING SESSILE DROPLET AT CONSTANT CONTACT LINE MODE

Tian-Shi Wang
College of Power Engineering, Chongqing University, Chongqing 400044, China

Wan-Yuan Shi
College of Power Engineering, Chongqing University, Chongqing 400044, China; Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Ministry of Education Chongqing 400044, China

DOI: 10.1615/IHTC16.cov.022860
pages 3053-3060


KEY WORDS: Convection, Boiling and evaporation, Bénard-Marangoni convection? thermocapillary convection

Abstract

Marangoni convection in an evaporating sessile droplet of silicone oil (0.65cSt) was experimentally investigated at constant contact line mode. A series of experiments were carried out in a wide range of the temperature of substrate in order to investigate the influence of temperature of substrate on Marangoni convection instability. We found that the convection in the evaporating sessile droplet when the temperature of substrate (Tw) is higher than ambient temperature (Ta) is different from that when Tw is lower than Ta. Three kinds of convection are observed with the droplet evaporating when Tw is higher than Ta, i.e., steady thermocapillary convection, steady Bénard-Marangoni (BM) convection and unsteady BM convection respectively. Hydrothermal waves (HTWs) are observed in the sessile droplet and the coexistence of HTWs and BM convection cells can also be investigated when Tw is lower than Ta. The critical contact angle for the onset of them are revealed through our experiments and we find that the critical contact angle increases with the increase of Tw when Tw is higher than Ta. With the increase of Tw, the number of Bénard-Marangoni convection cells increases during the stage of steady BM convection.

Purchase $25.00 Check subscription Publication Ethics and Malpractice Recommend to my Librarian Bookmark this Page