In contrast to the original form of the anode, the perforated anode is a new kind of anode that can significantly reduce the bubble thickness while maintaining a stable electrolysis process. The bubble movement was simulated within physical and mathematical models of the flow field in the anode–cathode distance (ACD) area, in which the electrolyte solidification zone in the anode perforations was treated creatively as a porous medium. The flow field distribution and the bubble layer thickness in the ACD area were simulated. The influence of the process parameters, such as the electrolyte temperature and ACD, on the flow field was analyzed. The results show that compared with the regular anode and slotted anode, the use of the perforated anode reduces the thickness of the bubble layer by approximately 1.63 and 1.06 mm, respectively. The velocity of the electrolyte is positively correlated with the electrolyte temperature, anode width, and bubble layer thickness. The immersion depth of the anode and the interanode gap have little effect on the bubble thickness and flow field.

A new method for the disposal of the spent refractory materials by adding them directly to electrolytic cells requires our better knowledge of the Na 3 AlF 6 −Al 2 O 3 −SiO 2 melt system. The development of computational materials science offers us a new way to avoid the limitation of the experiment under a strong corrosive environment at high temperatures. First-principles simulation is applied to study the structure information, electronic properties, and transport properties of the system. The study reveals that the main Si and Al ions in the melt are complex ion groups such as [SiF

A large amount of carbon dust is generated in the process of aluminum smelting by molten salt electrolysis. The carbon dust is solid hazardous waste but contains a large quantity of recyclable components such as carbon and fluoride. How to recycle carbon dust more effectively is a challenge in the aluminum electrolysis field. In this study, X-ray diffraction, scanning electron microscope, and other methods were used to analyze the phase composition of electrolytic aluminum carbon dust. The effects of particle size distribution of carbon dust, impeller speed, reagent addition, mixing time, and flotation time on the flotation recovery of carbon dust were studied. The optimal flotation conditions were obtained and the flotation products were analyzed. The results show that the optimal particle size distribution is 70% of particles below 200 mesh, corresponding to a grinding time of 11 min. The optimum speed of the flotation machine was to be between 1600 and 1800 r/min with the best slurry concentration of 20–30% and 5 min mixing time, and the collector kerosene was suitable for adding in batches. Under the above conditions, the recovered carbon powder with a carbon content of 75.6% was obtained, and the carbon recovery rate was 86.9%.

In accordance with high-speed schlieren results, the flow instabilities in the subsonic–supersonic mixing layer with a convective Mach number of 0.19 are investigated in detail. In the incipient stage of the mixing layer, wave structures caused by the pressure gradient affect the evolution of the Kelvin–Helmholtz vortexes. The dynamic mode decomposition (DMD) analysis reveals that the pressure gradient from the subsonic side to the supersonic side promotes flow instability. At this time, the Kelvin–Helmholtz vortexes mode is found to be dominant. A high temporal resolution is proven to play an important role in the DMD analysis to capture high-frequency modes.

This work experimentally studied the formation process of the ramjet mode occurring in a cavity-based combustor operating at a high-enthalpy supersonic flow. The ramjet mode is featured by the phenomenon that the incoming supersonic inflow is decelerated to be subsonic before it enters the combustor, which is caused by the strong heat release under a high equivalence ratio. In the experiments, the ignition is performed after a steady fuel mass flow rate has been achieved. According to the flame behavior and the flowfield structure, the formation process of the ramjet mode can be divided into three stages, among which stage 1 (from ignition to the cavity shear-layer mode) is shortest, while stage 3 (from the lifted shear-layer mode to the ramjet mode) consumes the longest time. In stage 2, flashback occurs and shock–shock interactions are found to be strongly coupled with the local combustion which have an influence on the propagation velocity of the backpressure. A thickening boundary layer upstream of the separation shock is observed when the separation shock has interwoven with the jet-induced bow-shock. The thickening process could be extremely short (in 100 μs) before the thickened boundary layer separates, during which the propagation velocity of the backpressure can be apparently decelerated. The same phenomena shown in the supplementary experiments confirm that the thickening boundary layer and its deceleration effect on the propagation of the backpressure are not accidental but more likely to be inherent to the flashback occurring under a supersonic flow.