Print Email Facebook Twitter The influence of surfactants on thermocapillary flow instabilities in low Prandtl melting pools Title The influence of surfactants on thermocapillary flow instabilities in low Prandtl melting pools Author Kidess, A. (TU Delft ChemE/Transport Phenomena) Kenjeres, S. (TU Delft ChemE/Transport Phenomena) Kleijn, C.R. (TU Delft ChemE/Transport Phenomena) Date 2016-06-17 Abstract Flows in low Prandtl number liquid pools are relevant for various technical applications and have so far only been investigated for the case of pure fluids, i.e., with a constant, negative surface tension temperature coefficient ∂γ/γT. Real-world fluids containing surfactants have a temperature dependent ∂γ/γT > 0, which may change sign to ∂γ/∂T <0 at a critical temperature Tc. Where thermocapillary forces are the main driving force, this can have a tremendous effect on the resulting flow patterns and the associated heat transfer. Here we investigate the stability of such flows for five Marangoni numbers in the range of 2.1 × 106 ≤ Ma ≤ 3.4 × 107 using dynamic large eddy simulations, which we validate against a high resolution direct numerical simulation. We find that the five cases span all flow regimes, i.e., stable laminar flow at Ma ≤ 2.1 × 106, transitional flow with rotational instabilities at Ma = 2.8 × 106 and Ma = 4.6 × 106, and turbulent flow at Ma = 1.8 × 107 and Ma = 3.4 × 107. To reference this document use: http://resolver.tudelft.nl/uuid:7a096593-15e9-47ad-b1b1-756bcf7a7c22 DOI https://doi.org/10.1063/1.4953797 Embargo date 2017-06-17 ISSN 1070-6631 Source Physics of Fluids, 28 (6) Part of collection Institutional Repository Document type journal article Rights © 2016 A. Kidess, S. Kenjeres, C.R. Kleijn Files PDF 6629934_Paper_the_influen ... ctants.pdf 10.43 MB PDF 1.4953797.pdf 5.38 MB Close viewer /islandora/object/uuid:7a096593-15e9-47ad-b1b1-756bcf7a7c22/datastream/OBJ1/view