scholarly journals Effect of Viscosity on the GTA Welds Bead Penetration in Relation with Surface Tension Elements

2016 ◽  
Vol 6 (2) ◽  
pp. 952-955
Author(s):  
K. Touileb ◽  
R. Djoudjou ◽  
A. Ouis
Keyword(s):  
Surface Tension ◽  
Stainless Steel ◽  
Viscous Dissipation ◽  
Molten Metal ◽  
Weld Pool ◽  
Marangoni Convection ◽  
Solid Compounds ◽  
Different Content ◽  
Bead Penetration

The aim of this paper is to study the effect of the viscous dissipation on the surface tension and its role on the shape of weld pool. Experiments were conducted on four different casts of ferritic stainless steel with different content in the sulfur and titanium. The results show in particular that the presence of titanium solid compounds affects the role of sulfur as surfactant element. Titanium in the presence of carbon and oxygen, titanium forms solid compounds which affect the Marangoni convection due to the sulfur element in the weld pool. The viscous dissipation due to these compounds alters the flow rate of the molten metal. We expect that the viscosity of metal liquid was altered by these solid compounds. The viscous dissipation due to these compounds contributes to heat the molten metal leading to larger weld bead.

Numerical Investigation of Transient Marangoni Effects on Weld Pool Dynamics in Gas Tungsten Arc Welding of Stainless Steel

2011 ◽  
Author(s):  
Debamoy Sen ◽  
Kenneth S. Ball ◽  
Mark A. Pierson
Keyword(s):  
Surface Tension ◽  
Stainless Steel ◽  
Weld Pool ◽  
Marangoni Convection ◽  
Driving Forces ◽  
Gta Welding ◽  
Flow Reversal ◽  
Surface Tension Gradient ◽  
Gas Tungsten Arc ◽  
Gas Tungsten

In this study, the fluid flow, heat transfer, and phase change occurring during the Gas Tungsten Arc (GTA) welding of stainless steel are numerically analyzed. Of all the driving forces involved during GTA welding, the Marangoni convection due to surface tension gradient is the most dominant. The amount of surfactant present in the metal strongly influences the strength, location, and direction of the Marangoni convection. Limited work has been done in the study of transient Marangoni convection behavior in the regime where a significant amount of surfactant is present, and depending on the thermal distribution in the molten metal pool, the surface tension gradient undergoes inflection, resulting in a flow reversal. The present investigation aims to address the complex relationship among the flow reversal, surfactant activity, and thermal pattern in the weld pool.

Everyday Products

2017 ◽  
Author(s):  
David Segal
Keyword(s):  
Stainless Steel ◽  
Hard Candy

Chapter 12 describes material aspects of everyday products. For example, the role of nanoparticles in sunscreens. It also covers surfactants and their role in micelles in washing-up liquids. The role of nanotechnology in cosmetics is stressed. The surprising use of hydrogels in disposable nappies (diapers) and the role of microstructure in sweets such as hard candy (boiled sweets) are described. Other everyday products include breathable garments, stainless steel and acrylic textiles.

On the Role of Marangoni Effects on the Critical Heat Flux for Pool Boiling of Binary Mixtures

1996 ◽  
Vol 118 (1) ◽  
pp. 103-109 ◽  
Author(s):  
W. R. McGillis ◽  
V. P. Carey
Keyword(s):  
Surface Tension ◽  
Heat Flux ◽  
Binary Mixtures ◽  
Critical Heat Flux ◽  
Full Range ◽  
Pool Boiling ◽  
Marangoni Effect ◽  
Restoring Force ◽  
Marangoni Effects

The Marangoni effect on the critical heat flux (CHF) condition in pool boiling of binary mixtures has been identified and its effect has been quantitatively estimated with a modified model derived from hydrodynamics. The physical process of CHF in binary mixtures, and models used to describe it, are examined in the light of recent experimental evidence, accurate mixture properties, and phase equilibrium revealing a correlation to surface tension gradients and volatility. A correlation is developed from a heuristic model including the additional liquid restoring force caused by surface tension gradients. The CHF condition was determined experimentally for saturated methanol/water, 2-propanol/water, and ethylene glycol/water mixtures, over the full range of concentrations, and compared to the model. The evidence in this study demonstrates that in a mixture with large differences in surface tension, there is an additional hydrodynamic restoring force affecting the CHF condition.

scholarly journals Influence of moisture content on the contact angle and surface tension measured on birch wood surfaces

2021 ◽  
Author(s):  
Rami Benkreif ◽  
Fatima Zohra Brahmia ◽  
Csilla Csiha
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Moisture Content ◽  
Solid Wood ◽  
Contact Angles ◽  
Surface Moisture ◽  
Wood Coatings ◽  
The Relationship ◽  
Wood Surfaces

AbstractSurface tension of solid wood surfaces affects the wettability and thus the adhesion of various adhesives and wood coatings. By measuring the contact angle of the wood, the surface tension can be calculated based on the Young-Dupré equation. Several publications have reported on contact angle measured with different test liquids, under different conditions. Results can only be compared if the test conditions are similar. While the roles of the drop volume, image shooting time etc., are widely recognized, the role of the wood surface moisture content (MC) is not evaluated in detail. In this study, the effect of wood moisture content on contact angle values, measured with distilled water and diiodomethane, on sanded birch (Betula pendula) surfaces was investigated, in order to find the relationship between them. With increasing MC from approximately 6% to 30%, increasing contact angle (decreasing surface tension) values were measured according to a logarithmic function. The function makes possible the calculation of contact angles that correspond to different MCs.

scholarly journals Interactions between an Associative Amphiphilic Block Polyelectrolyte and Surfactants in Water: Effect of Charge Type on Solution Properties and Aggregation

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1729
Author(s):  
Patrizio Raffa
Keyword(s):  
Surface Tension ◽  
Self Assembly ◽  
Interaction Model ◽  
Industrial Applications ◽  
Molecular Organization ◽  
Different Types ◽  
Solution Rheology ◽  
Interesting Class ◽  
First Time

The study of interactions between polyelectrolytes (PE) and surfactants is of great interest for both fundamental and applied research. These mixtures can represent, for example, models of self-assembly and molecular organization in biological systems, but they are also relevant in industrial applications. Amphiphilic block polyelectrolytes represent an interesting class of PE, but their interactions with surfactants have not been extensively explored so far, most studies being restricted to non-associating PE. In this work, interactions between an anionic amphiphilic triblock polyelectrolyte and different types of surfactants bearing respectively negative, positive and no charge, are investigated via surface tension and solution rheology measurements for the first time. It is evidenced that the surfactants have different effects on viscosity and surface tension, depending on their charge type. Micellization of the surfactant is affected by the presence of the polymer in all cases; shear viscosity of polymer solutions decreases in presence of the same charge or nonionic surfactants, while the opposite charge surfactant causes precipitation. This study highlights the importance of the charge type, and the role of the associating hydrophobic block in the PE structure, on the solution behavior of the mixtures. Moreover, a possible interaction model is proposed, based on the obtained data.

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