Доступ предоставлен для: Guest

ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

INFLUENCE OF DROPLET SIZE AND SURFACE-TENSION TEMPERATURE COEFFICIENT ON THE COALESCENCE OF TWO DROPLETS WITH DIFFERENT TEMPERATURES

Get access (open in a dialog) DOI: 10.1615/IHTC16.mpf.023184
pages 6271-6281

Аннотация

The coalescence between two droplets with various temperatures is one of the typical phenomena in the droplet microfluidics, for example, the photothermal effect induced droplets coalescence. In this study, the coalescence of two droplets with different temperatures in oil is simulated using the volume of fluid (VOF) method. The continuum surface stress (CSS) model is used to describe the interfacial tension force. The dynamic flow and heat transfer behaviors during the coalescence process is analyzed. Because the droplet size and the surface-tension temperature coefficient have important impacts on the temperature distribution, the pressure difference and thermocapillary flow, the main objective of this paper is to explore the effects of the droplet size and the surface-tension temperature coefficient on the coalescence. The results show that the coalescence of two droplets with different temperatures results in the self-propelled migration caused by the pressure difference arising from the temperature difference. The self-propelled distance is increased as the droplet size and the surface-tension coefficient increase. It is also found that the self-propelled direction changes for the case of large droplet and surface-tension temperature coefficient with negative sign, because the liquid water at the hot region migrates from one end to the other end driven by the thermocapillary flow. For the cases of positive surface-tension temperature coefficient, the self-propelled direction remains unchanged.