Multiphase flows in porous media are important in many natural and industrial processes. Pore-scale models for multiphase flows have seen rapid development in recent years and are becoming increasingly useful as predictive tools in both academic and industrial applications. However, quantitative comparisons between different pore-scale models, and between these models and experimental data, are lacking. Here, we perform an objective comparison of a variety of state-of-the-art pore-scale models, including lattice Boltzmann, stochastic rotation dynamics, volume-of-fluid, level-set, phase-field, and pore-network models. As the basis for this comparison, we use a dataset from recent microfluidic experiments with precisely controlled pore geometry and wettability conditions, which offers an unprecedented benchmarking opportunity. We compare the results of the 14 participating teams both qualitatively and quantitatively using several standard metrics, such as fractal dimension, finger width, and displacement efficiency. We find that no single method excels across all conditions and that thin films and corner flow present substantial modeling and computational challenges.

This work uses X‐ray computed micro‐tomography (μCT) to monitor xenon hydrate growth in a sandpack under the excess gas condition. The μCT images give pore‐scale hydrate distribution and pore habit in space and time. We use the lattice Boltzmann method to calculate gas relative permeability (krg) as a function of hydrate saturation (Shyd) in the pore structure of the experimental hydrate‐bearing sand retrieved from μCT data. The results suggest the krg ‐ Shyd data fit well a new model krg = (1‐Shyd)·exp(–4.95·Shyd) rather than the simple Corey model. In addition, we calculate krg‐Shyd curves using digital models of hydrate‐bearing sand based on idealized grain‐attaching, coarse pore‐filling, and dispersed pore‐filling hydrate habits. Our pore‐scale measurements and modeling show that the krg‐Shyd curves are similar regardless of whether hydrate crystals develop grain‐attaching or coarse pore‐filling habits. The dispersed pore filling habit exhibits much lower gas relative permeability than the other two, but it is not observed in the experiment and not compatible with Ostwald ripening mechanisms. We find that a single grain‐shape factor can be used in the Carman‐Kozeny equation to calculate krg‐Shyd data with known porosity and average grain diameter, suggesting it is a useful model for hydrate‐bearing sand.

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In this study, the effect of adding glass ionomer (GI) Restorative Cement (0−30 wt%) on the mechanical and thermo‐mechanical characterization of dental composite has been discussed. The characterization of dental composites was done by performing Fourier transform infrared spectroscopy, hardness test, compression test, flexural strength test, dynamic mechanical analysis (DMA), thermo gravimetric analysis (TGA). The finding of experiments indicated that the addition of 10 wt% of GI increased the water hardness, flexural strength and compressive strength by 88.48, 15.95, and 17.74%, respectively. DMA results revealed that the storage modulus was initially increased by 88% when GI was increased up to 20 wt%, however, further increase of GI up to 30 wt% resulted in decrease in the storage modulus by 16.4%. Also, loss modulus was increased by 41.6% when GI was increased by 10 wt%, however, it was further decreased by 2.94% and by 35.29% on addition of GI filler content up to 20 and 30 wt%, respectively. Incorporation of GI up to 10 wt% decreased the damping factor by 36.36% but further addition of GI up to 20 and 30 wt% increased the damping factor of dental composite by 14.2 and 50%. TGA indicated that thermal degradation temperature was increased with the addition of GI filler. POLYM. COMPOS., 40:3361–3367, 2019. © 2018 Society of Plastics Engineers