Wettability effects

The capillary effect is apparent whenever two non-miscible fluids are in contact, and is a result of the interaction of attractive forces between molecules in the two liquids (surface tension effects), and between the fluids and the solid surface (wettability effects). 

The overall gain of the multiphase mixture model approach above is that the two-phase flow is still considered, but the simulations have only to solve pseudo-one-phase equations. Problems can arise if the equations are not averaged correctly. Also, the pseudo-one-phase treatment may not allow for pore-size distribution and mixed wettability effects to be considered. Furthermore, the multiphase mixture model predicts much lower saturations than those of Natarajan and Nguyen - and Weber and Newman even though the limiting current densities are comparable. However, without good experimental data on relative permeabilities and the like, one cannot say which approach is more valid. 

Mungan, N., 1966a. Certain wettability effects in laboratory waterfloods. IPX (February), 247-252. 

Before any further calculations, the water saturation in the microscopic model developed above should be calibrated to experimentally determined values. The saturation discrepancy between the model and reality results mainly from two sources that the microscopic model cannot address one is connate water saturation (Swc) and immobile oil saturation (Sd) the other is the wettability effect of irregular particle surfaces. If we assume that water saturation remains as a constant (S g) until water breakthrough occurs, the calibration can be carried out as... 

Wettability Effects on Relative Permeability/Saturation Relationships... 

This example demonstrates that the approach taken is able to reflect well wettability effects on the fuel cell performance. Combined with the corresponding experiments to investigate the two-phase flow behavior of the PTL, it can be considered as a working, albeit pragmatic modeling approach for theses processes. 

Further differences are found in the way the models account for wettability effects. These effects can be explicitly accounted in the spreading diameter by introducing the contact angle in the term of the surface energy of the spreading droplet, sf as (e.g., [8]), sf = /A)ndp a y — cos 6), where some authors use... 

In conclusion, a simple and practical method of scraping was proposed to construct large-scale rough structures on polymer surfaces so as to control their surface wettability effectively. This method can be readily extended to most of the engineering plastics and to enhance the hydrophilicity of hydrophilic polymers as well as the hydrophobicity of hydrophobic ones. Importantly, this study sheds some light on the new boundary between hydrophilicity and hydrophobicity from the physicochemical viewpoint, which may offer a promising future for practical applications. 

A detailed description of the wettability effects was presented by Benner, Riches and Bartell in 1938 (12) when they described not only wettability, but other aspects of the influence of surface chemistry on oil recovery. As director of API Project... 

Finally, composition gradients from two different polymer chains have also been used to study wettability effects. A polystyrene poly(2-vinylpyridine) gradient allows a switchable wettability if submitted to a selective solvent treatment. In the selective solvent, one of the two chains collapses and the properties of the surface are determined by mainly the other component. The same effect can be exploited when submitting a polyelectrolyte gradient (poly(tert-butylacrylate) vs. poly(2-vinylpyridine)) to a pH change, Fig. 19. 

Chen YM, Fan LS. Bubble breakage due to particle collision in a liquid medium particle wettability effects. Chem Eng Sci 44 2762-2767, 1989b. 

Tsutsumi A, Nieh JY, Fan LS. Particle wettability effects on bubble wake dynamics in gas-liquid-solid fluidization. Chem Eng Sci 46 2381-2384, 1991a. 

In this expression, Fnp is the surface atom ratio of catalyst nanoparticles, Tstat accounts for percolation and wettability effects that diminish the statistical utilization of the catalyst, and the function / (structure, conditions) incorporates all effects due to nonuniform reaction rate distributions. 

Photoinduced superhydrophilication due to water-attracting hydroxyl groups (-OH) - High water-wettability effect... 

Sonoyama N, Iguchi M (1999) Wettability effects on bubble characteristics in a bubbling wall jet along a vertical flat plate. ISIJ Int 39 673-679... 

Terauchi Y, Iguchi M, KosakaH, Yokoya S, Kara S (1999) Wettability effect on the flow pattern of air—water two-phase flows in a vertical circular pipe, Tetsu-to- Hagane 85 645-651... 

Generally speaking, acid-removable skin is a reduction in permeability, caused by plugging or constriction in pore throats, that can be removed by acid. Non-acid-removable skin includes changes to the pore structure resulting in increased resistance to flow, such as wettability effects. Resistance to flow also may result from plugging by acid-insoluble materials, such as certain scales, paraffin (wax), and asphaltenes. 

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