The flow field within a droplet located on a flat heated surface -Influence of the heat transfer boundary conditions
2013 (English)Conference paper, Presentation (Other academic)
Evaporation of droplets on heated surfaces is important in a number of applications including the drying of paint and cooling of electronics. Questions are addressed both towards increasing the drying rate as well as on how to control the deposition of particles suspended in the fluid. This work aims to numerically investigate how the heat and mass transfer boundary condition at the droplet surface should be presented in order to fully represent the surrounding fluid flow. With aid of Computational Fluid Dynamics, a numerical study is therefore carried out to determine the general consequence of using a local heat transfer coefficient and how it affects the separate mechanisms of the internal flow in particular. Results show that the application of a local heat transfer boundary condition is important only if the internal velocity of the fluid inside the droplet is small. If the surface tension is high, i.e. if the flow is dominated by Marangoni convection, the surface temperature is instead controlled by the internal mixing rather than the local heat transfer. For the conditions studied, Marangoni convection is dominating and will enhance the drying rate when compared to the influence of conduction and natural convection.
Place, publisher, year, edition, pages
Research subject Fluid Mechanics
IdentifiersURN: urn:nbn:se:ltu:diva-29973Local ID: 39cb56b8-2c3a-4c29-9246-93aeaa19cb6dOAI: oai:DiVA.org:ltu-29973DiVA: diva2:1003200
EuroDrying : 02/10/2013 - 04/10/2013
Godkänd; 2013; 20131125 (annlju)2016-09-302016-09-30Bibliographically approved