Heat and mass transfer at a free surface with diabatic boundaries in a single-species system under microgravity conditions

2014 ◽  
Vol 55 (6) ◽  
Author(s):  
Eckart Fuhrmann ◽  
Michael E. Dreyer
Keyword(s):  
Mass Transfer ◽  
Free Surface ◽  
Heat And Mass Transfer ◽  
Single Species ◽  
Microgravity Conditions

Effects of interface conditions on heat and mass transfer during modeling of laser dissimilar welding

2021 ◽  
pp. 095440622110138
Author(s):  
Zhiyong Li ◽  
Gang Yu ◽  
Xiuli He ◽  
Shaoxia Li ◽  
Xu Wang ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Free Surface ◽  
Heat And Mass Transfer ◽  
Surface Deformation ◽  
High Energy ◽  
Dissimilar Welding ◽  
Transfer Model ◽  
Interface Conditions ◽  
Substrate Interface ◽  
Free Surface Deformation

An improved 3 D heat and mass transfer model was developed to study the effects of interface conditions during modelling of laser dissimilar welding. In detail, the interface conditions consist of the physical processes at gas/liquid surface (e.g. free surface deformation and optical absorptance), substrate interface (e.g. mixture properties in liquid phase and thermal contact condition) and solid/liquid interface (e.g. fusion line). Their effects on heat and mass transfer are numerically and experimentally analyzed, which are all non-negligible in the welding modelling. In conclusion, free surface deformation influences convection flow and should be considered in the situation of micro-welding and high energy-input welding. Besides, the energy transfer between laser and substrate is more reasonably described by the optical absorptance expressed in polynomial function. The mass transfer induced variation of mixture properties is well described by the method based on time-dependent mixture fraction. Thermal resistance between clamp and substrate should be considered in the modelling of temperature field on macroscale. The joint conductance at substrate interface could be neglected when modelling heat and mass transfer inside the melt pool, while it should be calculated in the simulation of temperature distribution based on the mechanism of heat conduction. The obtained results in this paper provide a vital insight into the interface conditions in laser dissimilar welding process.

scholarly journals Heat and mass transfer during evaporation from a free surface of water flowing through fibrous sheet in an inclined enclosure.

1987 ◽  
Vol 20 (6) ◽  
pp. 579-584 ◽  
Author(s):  
SHIGEKI TOYAMA ◽  
TSUTOMU ARAGAKI ◽  
HASSAN MOHAMED SALAH ◽  
KAZUNORI MURASE
Keyword(s):  
Mass Transfer ◽  
Free Surface ◽  
Heat And Mass Transfer ◽  
Inclined Enclosure

scholarly journals Convection in Superposed Liquid and Porous Layers with Heat and Mass Transfer at the Free Surface

2021 ◽  
Author(s):  
Rita Kozak
Keyword(s):  
Mass Transfer ◽  
Free Surface ◽  
Heat And Mass Transfer ◽  
Porous Layers

Convection in Superposed Liquid and Porous Layers with Heat and Mass Transfer at the Free Surface

scholarly journals The Instability of an Electrohydrodynamic Viscous Liquid Micro-Cylinder Buried in a Porous Medium: Effect of Thermosolutal Marangoni Convection

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Galal M. Moatimid ◽  
Mohamed A. Hassan
Keyword(s):  
Mass Transfer ◽  
Surface Tension ◽  
Free Surface ◽  
Dispersion Relation ◽  
Electric Field ◽  
Heat And Mass Transfer ◽  
Viscous Liquid ◽  
Marangoni Convection ◽  
Axial Electric Field ◽  
Stabilizing Effect

The electrohydrodynamic (EHD) thermosolutal Marangoni convection of viscous liquid, in the presence of an axial electric field through a micro cylindrical porous flow, is considered. It is assumed that the surface tension varies linearly with both temperature and concentration. The instability of the interface is investigated for the free surface of the fluid. The expression of the free surface function is derived taking into account the independence of the surface tension of the heat and mass transfer. The transcendental dispersion relation is obtained considering the dependence of the surface tension on the heat and mass transfer. Numerical estimations for the roots of the transcendental dispersion relation are obtained indicating the relation between the disturbance growth rate and the variation of the wave number. It is found that increasing both the temperature and concentration at the axial microcylinder has a destabilizing effect on the interface, according to the reduction of the surface tension. The existence of the porous structure restricts the flow and hence has a stabilizing effect. Also, the axial electric field has a stabilizing effect. Some of previous analytical and experimental results are recovered upon appropriate data choices.

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