Topic
Marangoni effect
About: Marangoni effect is a research topic. Over the lifetime, 5336 publications have been published within this topic receiving 98562 citations. The topic is also known as: Gibbs–Marangoni effect.
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07 Dec 2012
TL;DR: In this article, the authors developed a Computational Fluid Dynamics model to study steel weld pool hydrodynamics during conduction mode laser spot welding, and concluded that free surface deformations and instabilities have a strong impact on the fluid flow and heat transfer in weld pools, and should therefore be accounted for in weld pool simulations.
Abstract: Extending the weldability of novel materials, and improving the weld quality by tailoring weld microstructures are key factors to obtain the welding techniques demanded in the modern manufacturing industries. This can be done, for example, by feeding chemical elements from a consumable wire into the weld pool during welding. The mixing of chemical components in the weld pool and the resulting post-solidification weld microstructures are influenced by weld pool hydrodynamics. Weld pool hydrodynamics is known to be primarily driven by Marangoni forces acting at the free liquid surface, i.e by tangential gradients in surface tension along the liquid surface due to pronounced lateral gradients in temperature and surface active element concentration. In this research, we develop a Computational Fluid Dynamics model to study steel weld pool hydrodynamics during conduction mode laser spot welding. It is concluded that free surface deformations and instabilities have a strong impact on the fluid flow and heat transfer in weld pools, and should therefore be accounted for in weld pool simulations. With increasing the surface active element concentration and laser power, the weld pool flow becomes highly unstable and can no longer be accurately modeled with a flat surface assumption. More accurate predictions of weld pool physics can be made if the free surface, solidification stage, and three-dimensionality are taken into account. This reduces the need for the use of unphysical parameter fittings widely reported in literature.
54 citations
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TL;DR: In this paper, a previously developed mathematical wetting model is generalized and applied to the following two closely related situations: the spreading of a liquid over a prewet solid surface and the receding contact-line motion with a microscopic residual film, remaining behing the contact line.
Abstract: A previously developed mathematical wetting model is generalized and applied to the following two closely related situations: the spreading of a liquid over a prewet solid surface and the receding contact-line motion with a microscopic residual film, remaining behing the contact line. An analytical expression for the velocity dependence of the dynamic contact angle is derived. Macroscopic characteristics (the dynamic contact angle and drag force) and the flow field corresponding to the spreading of a liquid over a wet solid surface differ considerably from those calculated for a dry surface. Under certain conditions the flow in the reference frame fixed with respect to the contact line has a region with closed streamlines. The region appears due to the flow-induced Marangoni effect, the reverse influence of the surface tension gradient along the liquid-solid interface caused by the flow on the flow, which gives rise to the gradient. The results are compared qualitatively with experimental data
54 citations
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TL;DR: A double-shielded TIG method was proposed to improve weld penetration and has been compared with the traditional TIC welding method under different welding parameters (i.e., speed, arc length and current).
54 citations
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TL;DR: In this paper, the authors address the coupled heat transfer and fluid dynamic modeling of the SiC solution growth process, with special attention being paid to the different convective flows in the liquid.
54 citations
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TL;DR: In this paper, the development of instabilities under the joint action of van der Waals forces and Marangoni stresses in a two-layer film on a heated or cooled substrate is considered.
Abstract: The development of instabilities under the joint action of the van der Waals forces and Marangoni stresses in a two-layer film on a heated or cooled substrate, is considered. The problem is solved by means of a linear stability theory and nonlinear simulations. Nontrivial change of the droplet shape in the presence of the Marangoni effect, which manifests itself as the deformation of a “plateau” into an “inkpot,” is observed. The appearance of the threshold oscillations predicted by the linear stability theory is confirmed by nonlinear simulations.
54 citations