Papers by Author: X.F. Yang

Abstract: In this paper, a numerical two-phase flow model combining with the Realizable k–ε turbulent model for compressible viscous fluid is presented for the computation of water drop falling characteristics; and the equations are solved with the finite volume method. The free fluid surface is simulated by the VOF method. A multigrid technique based on the full approximation storage (FAS) scheme is employed to accelerate the numerical convergence. The numerical results for water drop suggest that this basic model can be used to study violent aerated flows, especially by providing fast qualitative estimates.

Abstract: This paper is concerned with the numerical study of gas–liquid flow in bubble columns by large eddy simulations (LES). The Euler–Euler approach is used to describe the equations of motion of the two-phase flow. The mean velocities and the fluctuating velocities are obtained. It is found that, when the drag, lift and virtual mass forces are used, the computed results in agreement with experimental transient behavior can be captured.

Abstract: Nested type Fixed-Cone Valve, numerical simulation, energy dissipating, turbulent flow Abstract: In this paper, In this paper, a new type of Fixed-Cone Valve was proposed by improving the conventional type Fixed-Cone Valve .The flow fields of the two kinds of Fixed-Cone Valves were studied by using numerical simulation method .The computed pressure fields and the velocity fields were analyzed ,which shows that under the same conditions ,and by using the nested Fixed-Cone valve, the pressure of the upstream pipe and the cone valve and the average velocity along the downstream pipeline are reduced ,but the rate of energy dissipation is increased.

Abstract: n-doped ZnO (ZnO:In) thin films with 0~9at.% In content have been prepared by RF high magnetron sputtering on glass substrate. All the films were annealed in N₂ at 473K for 1h. The effect of In doping concentration on the structure, surface morphology, electrical properties,Seebeck and magnetoresistive effect of the films were investigated. It was found that the crystal quality of the films degrades, and the surface gets rough with increasing In content. The lowest resistivity of the ZnO:In thin films 6.1×10^-4Ω.cm occurs at 5at.% in the target doping concentration. All the films show a striking Seebeck effect and the absolute value of the Seebeck coefficient decreases under magnetic field. Meanwhile, a positive magnetoresistance of the films was found. ZnO thin films with 1at.% In-doped is best for the thermoelectric material, which has the largest power factor of 2.1×10^-4W/K²m at room temperature.