Electrochemical oxygen reduction reaction (ORR) is a powerful tool for introducing oxygen functional groups in synthetic chemistry. However, compared with the well-developed one-electron oxygen reduction process, the applications of two-electron...

The 0.54%(Pt, Rh, Pd or Ru)/Co(OH)2, 1.23%Rh/Co(OH)2 catalysts were successfully synthesized by simple hydrothermal and precipitation methods for nitroarenes selective hydrogenation, it was found that 0.54%Rh/Co(OH)2 outperformed other catalysts, for...

Aiming at the spraying process of airless atomization spraying, a coating film forming model based on Euler-Lagrangian method is proposed. A Rosin-Rammler atomization model was established. In the spraying model, for the discrete phase, a force balance equation is established. At the same time, a continuity equation and a momentum equation are established to describe the motion of the continuous phase. The momentum equation of the continuous phase is closed by the standard k-ε model. The continuity equation and momentum equation are established in the adhesion deposition model to solve the coating thickness. PC-SIMPLE algorithm was used to solve the model. Finally, the dynamic spraying simulation is verified through experiments, and the numerical simulation results are in good agreement with the experiments as a whole. It is proved that the film forming model can be used to predict the film forming results of airless spraying.

Based on the computational fluid dynamics (CFD) theory, this paper proposes a film formation model and a numerical simulation method that can be used in thickness prediction of airless spraying robots. The spraying flow field and the film formation process in the airless spraying process were simulated by the Eulerian–Eulerian approach, and the airless spraying film formation model including the paint expansion model and the wall hitting model was established. To verify the correctness of the model, numerical simulations of static spraying and dynamic spraying were carried out on the plane and arc surfaces. The simulation results showed that the width of the spraying flow field on the far wall increased linearly with the longitudinal distance in the major-axis direction. The busbar spraying on the outer surface of the arc surface showed the similar characteristics to the plane in the major-axis direction. Besides, the annular spraying was similar to the plane spraying in the minor-axis direction, but the inner surface spraying was completely opposite. When spraying the outer surface, the film thickness increased with the increase of the inner diameter but was smaller than that of the plane spraying, while the inner surface spraying was completely opposite. In the spraying experiment, the plane dynamic spraying and the arc plane inner and outer surface translation spraying were selected for verification. The experimental results were in good agreement with the simulation results, indicating that the film formation model of airless spraying established in this paper is basically correct. As a result, this model can be used for thickness prediction of spraying robots.

Research on spraying models of special profiles has a great significance on optimizing spraying quality, saving paint and protecting environment and health of workers. This article establishes a paint deposition model including the spray flow field model and impact adhesion model based on the Euler-Euler method. The model is solved by using polyhedral mesh to divide the fluid calculation domain and the coupled SIMPLE algorithm to compute the governing equations. The methods of spraying along the bus bar and circumferential spraying are applied to simulate and test the conical surface and the arc surface successively. Results of the experiments demonstrate the errors of the four cases are all less and confirm that the established paint deposition model is suitable for spraying research on conical outer surface.