The reliability and accuracy of numerical results of microparticle fluidization in a conical bed, affected simultaneously by mesh refinement, the grid configuration and the wall boundary condition (BC), are analyzed. ...The reliability and accuracy of numerical results of microparticle fluidization in a conical bed, affected simultaneously by mesh refinement, the grid configuration and the wall boundary condition (BC), are analyzed. Specifically, pressure gradients and velocity profiles of titania powder are studied for a conical bed. The Gidaspow drag correlation and different wall BCs are considered using a Eulerian-Eulerian two-fluid model. Predictions of the pressure fluctuation, power spectra of the corresponding pressure fluctuations, bed pressure drop, minimum fluidizati on veloc ity, axial solid velocity, bed expansi on ratio, and particle size distribution are compared with experimental data. Mesh sensitivity analysis using hexahedral and tetrahedral cells with a un iform mesh and n ear-wall mesh refineme nr is con ducted to inv estigate the effects of mesh configurations in estimating particle flow patterns. Simulations show that significant savings in terms of computational time are realized by choosing a uniform mesh while the hexahedral structure, the near-wall mesh refinement, and the free-slip BC give the closest fit to the experimental data.展开更多
文摘Grady Booch因在软件架构(software architecture)、建模(modeling)和软件工程过程(software engineeringprocess)方面的开创性工作而闻名于世。自1980年Rational软件公司创立以来,他一直拉任该公司的首席科学家。Grady是统一建模语言(UML)最早的开发者之一。他是六本计算机科学畅销书的作者,其著作包括《The Unified ModelingLanguage User Guide》(Addison-Wesley,1999)、具有开创意义的《Object-oriented Analysis and Design with Applications》(Addison-Wesley,1994)。MSDN Magazine最近抓信Grady,请他谈谈Microsoft.NET和Visual Studio.NET对于软件开发世界的影响。
文摘The reliability and accuracy of numerical results of microparticle fluidization in a conical bed, affected simultaneously by mesh refinement, the grid configuration and the wall boundary condition (BC), are analyzed. Specifically, pressure gradients and velocity profiles of titania powder are studied for a conical bed. The Gidaspow drag correlation and different wall BCs are considered using a Eulerian-Eulerian two-fluid model. Predictions of the pressure fluctuation, power spectra of the corresponding pressure fluctuations, bed pressure drop, minimum fluidizati on veloc ity, axial solid velocity, bed expansi on ratio, and particle size distribution are compared with experimental data. Mesh sensitivity analysis using hexahedral and tetrahedral cells with a un iform mesh and n ear-wall mesh refineme nr is con ducted to inv estigate the effects of mesh configurations in estimating particle flow patterns. Simulations show that significant savings in terms of computational time are realized by choosing a uniform mesh while the hexahedral structure, the near-wall mesh refinement, and the free-slip BC give the closest fit to the experimental data.
