Laminar, steady-state, natural convection of power-law fluids in 2-D trapezoidal enclosures with a heated bottom wall, adiabatic top wall and cooled inclined sidewalls has been analyzed for the first time based on numerical simulations for a range of different values of nominal Rayleigh number (i.e. ${10}^3\le Ra\le {10}^5$), power-law index (i.e. $0.6\le n\le 1.8$), nominal Prandtl number (i.e. $Pr={10, 10}^2,{10}^3$) and sidewall inclination angle (i.e. $30°\le \varphi \le 60°$). It has been found that the mean Nusselt number $\overline{Nu}$ increases with increasing nominal Rayleigh number $Ra$ (up to a 187% increase for $n=0.6$ and up to 2.3% increase for $n=1.8$ between $Ra={10}^3$ and ${10}^5$) and decreasing power-law index $n$ (up to a 4.1% increase for $Ra={10}^3$ and up to 193% increase for $Ra={10}^5$ between $n=0.6$ and 1.8) due to the strengthening of advective transport. Moreover, an increase in the sidewall inclination angle $\varphi$ leads to a decrease in $\overline{Nu}$ (approximately 44% decrease for $Ra={10}^3$ across values of $n$ and up to 33% decrease for $Ra={10}^5$ across values of $n$) due to an increase in the area for heat loss from the cavity. It has been found that $\overline{Nu}$ does not vary significantly with the values of $Pr$ considered in the current study. Furthermore, a new correlation for the mean Nusselt number $\overline{Nu}$ in this configuration has been identified which provides adequate approximation of the corresponding values obtained from the simulations.

Commercially available 316L (1.4404) stainless steel is commonly used for industrial filtration due to its combination of good material properties, particularly its corrosion resistance, which is a critical factor for filters in corrosive (e.g., saltwater) environments. Recently, laser powder bed fusion (LPBF) has enabled new more complex and efficient filtration pieces to be manufactured from this material. However, it is critical to know how the corrosion resistance is affected by this manufacturing strategy. Here, the corrosion resistance of LPBF manufactured 316L stainless steel is compared with wrought 316L sheet. The corrosion of the samples in saltwater was assessed with asymmetric electrochemical noise, potentiodynamic polarisation curve, and electrochemical impedance spectroscopy. The samples before and after corrosion were examined with scanning electron microscopy and energy-dispersive spectroscopy. The LPBF samples had higher corrosion resistance than the sheet samples and were more noble. The corrosion resistance of the LPBF sample increased with time, while the wrought sample corrosion resistance reduced over time. The corrosion mechanism of both samples was stable with time, formed of a passive film process and a bared material process. This paper presents the first study about the temporal evolution of the LPBF 316L stainless steel corrosion mechanism.

A three-dimensional direct numerical simulation database of an open turbulent jet spray flame representing a laboratory-scale burner configuration has been analyzed to investigate flame self-interactions (FSIs) in the presence of flow induced shear, to the best of the authors' knowledge, for the first time. The FSI occurrences [i.e., unburned gas mixture pockets (UBGPs), tunnel formations (TFs), tunnel closures (TCs), and burned gas mixture pockets (BGPs)] have been identified across the flame at different axial locations. It has been found that the interplays between turbulence, droplet evaporation, and chemistry have a significant influence on the topological nature of the flame surface. Close to the jet exit, the FSI events are found to occur toward the burned gas side of the flame, but moving further away from the jet exit, there are significant occurrences of FSI events within the flame where increasingly fuel-rich, low Damköhler number conditions occur. In this study, the FSI events have been found to be predominantly TFs and TCs, which is consistent with previous analyses of turbulent premixed flames and combustion of droplet-laden mixtures. However, non-negligible occurrences of UBGPs and BGPs are also observed in this case. The results obtained from this analysis have important implications from a modeling perspective where flame topologies have a significant influence on the nature of the flame surface, which will, in turn, affect the flame-surface based modeling approaches. Accordingly, the findings of the current analysis may need to be accounted for during the development of flame surface-based closures in the context of turbulent spray flames.