Surface tension simulation results

A more sophisticated approach for determination of the grain boundary segregation is similar to the determination of the surface tension of silicon melt. The novel approach of surface tension simulation has been successfully implemented in the thermochemical database. Hence, the assessment of the parameters for impurity segregation in solid silicon phase may greatly extend the application of the thermochemical database. The calculation results for C and O segregation are shown as dashed lines in Fig. 13.28. The McLean segregation isotherm can be reproduced using the approach similar to the surface tension simulation. 

FIG. 3 The calculated surface tension of an argon-methane mixture as function of composition (mole fraction of argon) is shown as open circles in comparison with corresponding simulation results obtained by Mecke, Winkelmann, and Fischer [J. Chem. Phys. //0 1188 (1999)]. The GvdW(HS-B2) functional was used with tanh(w, x) profiles. 

The simulation results on bubble velocities, bubble shapes, and their fluctuation shown in Fig. 3 are consistent with the existing correlations (Fan and Tsuchiya, 1990) and experimental results obtained in this study. Bubble rise experiments were conducted in a 4 cm x 4 cm Plexiglas bubble column under the same operating conditions as those of the simulations. Air and tap water were used as the gas and liquid phases, respectively. Gas is introduced through a 6 mm nozzle. Note that water contamination would alter the bubble-rise properties in the surface tension dominated regime. In ambient conditions, this regime covers the equivalent bubble diameters from 0.8 to 4mm (Fan and Tsuchiya, 1990). All the air-water experiments and simulations of this study are carried out under the condition where most equivalent bubble diameters exceed... 

Comparing the 3-D images simulated and the experimental photographs in Fig. 10, it can be seen that the droplet shapes are well reproduced by the present model. During the first 3.5 ms of the impact (frames 1-3), a liquid film with flattened disc shape is formed immediately after the impact. The inertial force drives the liquid to continue spreading on the solid surface, while the surface tension and the viscous forces resist the spreading of the liquid film. As a result, the droplet spreading speed decreases and the fluid mass starts to accumulate at... 

To show this, we will present and discuss some typical results readily available in the literature. Here we will select systems simulated in the constant-pressure constant-surface-tension ensemble, i.e. with a temperature, pressure and surface tension control. 

Finally, we compare the results of our calculations with the computer simulation results of Thompson et al. (7) in Figure 6. In these studies the surface tension was determined by a direct evaluation of the pressure tensor. Equations 12 and 13 were combined, replacing R with Equation 9 to obtain... 

The statistical quality of simulation estimates of the pressure tensor was poor near the origin resulting in large uncertainties in the estimate of the surface tension through Equation 24. By combining a truncated Taylor series expansion of Equation 20 with Equation 9 they obtained... 

The radially dependent surface tension predicted by YBG theory are compared with the results of computer simulation using equations (24) (o) and (25) ( ). The estimated error bars are taken from reference 7. 

In addition to the simulation results on the structure of interfaces, reported so far in FICS, we shall now give some outcomes on surface and interfacial tensions. In so doing, we msike the conscious decision to omit most of the technical details (numbers of molecules and time steps, interaction functions, accounting for internal degrees of freedom etc.) although the results depend, sometimes critically, on these. Therefore, our examples merely serve as illustrations of the achievements. 

Here, A is the stationary-state thermal conductivity and q is the heat of transfer. The results of the simulations for A and q ate shown as a function of surface tension in Figures 3 and 4. The transfer coefficients decrease in magnitude as we move from the critical point in the phase diagram (zero surface tension) to the triple point (maximum surface tension). It is reasonable that the surface becomes more resistive at high surface... 

The objective of this paper is to demonstrate the importance of phase and reaction equilibria considerations in the rational development of SCF reaction schemes. Theoretical analysis of phase and reaction equilibria are presented for two relatively simple reactions, viz., the isomerizations of n-hexane and 1-hexene. Our simulated conversion and yield plots compare well with experimental results reported in the literature for n-hexane isomerization (4) and obtained by us for 1-hexene isomerization. Based on our analysis, the choice of an appropriate SCF reaction medium for each of these reactions is discussed. Properties such as viscosity, surface tension and polarity can affect transport and kinetic behavior and hence should also be considered for complete evaluation of SCF solvents. These rate effects are not considered in our equilibrium study. 

---