Vertical axis wind turbine (VAWT) is a competitive power generation device due to structural simplicity, wind direction independence, no yaw mechanism required, easier maintenance, and lower noise emission. However, blade tip vortex will be generated at both ends of the blade during the rotation, resulting in torque loss and efficiency reduction. In this paper, computational fluid dynamics is used to study blade tip vortex and its reduction technique of a single-blade VAWT rotor in real scale. By monitoring the force and flow field at different heights of the blade, the influence ranges of tip vortex are obtained. The reduction effect of the bulkhead obtained from the blade profile curve is studied, and the size of the bulkhead is optimized. On the basis of adding the optimal bulkhead, the influence of the supporting strut is also explored. The joint action is obtained by changing the location of the supporting strut. The results show that the top supporting strut-bulkhead structure is the optimal position. The power-extraction efficiency of the rotor with this integrated structure is significantly improved at optimal tip speed ratios (TSRs) and higher TSRs.

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The Y-shaped elbow is used as a connecting pipe between the buffer and the lift pipe in the deep-sea mining system. After being mixed with seawater in the Y-shaped elbow, nodule particles are lifted to the sea surface mining ship via the lift pump. In this paper, we employ a computational fluid dynamics and discrete element coupled method (CFD-DEM) to study the characteristics of particle transport in the Y-shaped elbow. Considering a large diameter of the particles, we discuss the behavior of particles and fluid under different conveying velocities. In addition, the simulation was verified based on the experiment. The results show that the simulation agrees well with the experiment. On this basis, the distribution and motion characteristics of the particles in the Y-shaped elbow were obtained. The interaction between fluid and particles is also discussed. These findings suggest that the particles can be successfully transported when the pump runs at medium to high frequencies. The particles are basically moving along the pipe wall and slower than the fluid flow. Moreover, it was found that the particle motions are more complex with the increasing of conveying velocities, and it is closely related to the secondary flow of fluid. Some suggestions on the actual particle transportation can be put forward based on the research in this paper.

Voronoi tessellations are shown to be statistically representative of polycrystalline microstructures, which have been widely accepted for the modeling of microstructures of metallurgic and ceramic materials. In this paper, a new implementation of the Voronoi diagram in Laguerre geometry is presented for the generation of numerical models of polycrystalline microstructures, where the size and shape of the grains can be controlled, and the 3D grain boundaries can be modeled with a specified thickness. The distribution of grain sizes in the models is fitted to a lognormal distribution, compared with the normal distribution in the Voronoi tessellation methods. Finally, statistical analyses of grain face and grain size distribution are performed with the models, and the macroscopic elastic properties of polycrystalline ceramic materials are simulated to verify the capability of the presented method.

An efficient and scalable synthesis of eliglustat (1) is herein reported. This novel route features a three-step telescoped process to afford the α-dibenzylamino β-ketoester 6 in 85% overall yield from commercially available 1,4-benzodioxane-6-carboxylic acid 7. The key intermediate 5 was obtained via an efficient ruthenium-catalyzed DKR-ATH reaction, which afforded the desired product in 90% isolated yield with >99:1 dr and 99.7% ee on a 100 g scale. In addition, the amidation of sterically hindered carboxylic acid 14 was optimized and amenable to scale-up. This process not only gives a desirable total yield but also avoids hazardous conditions and chromatographic purification. The robustness of this synthesis was successfully performed on a multigram scale to afford 1 with >99.9% de and >99.9% ee in 56.8% overall yield in nine steps.