Deterministic simulation approach was applied to simulating viscoelastic complex flows,in which,the SIMPLE algorithm based on collocated grid was used to solve the conservation equations on the macroscopic level and t...Deterministic simulation approach was applied to simulating viscoelastic complex flows,in which,the SIMPLE algorithm based on collocated grid was used to solve the conservation equations on the macroscopic level and the spectral method was used to solve the Fokker-Planck equation on the mesoscopic level.Here,the transient 4∶1 planar contraction flow for dilute polymer solution was computed by using the coupled technique and the calculated polymeric stress distributions at steady state were identical with the results of continuum approach as well as the corresponding references.Therefore,the presented results indicated that the SIMPLE algorithm based on collocated grid coupled with the spectral method can be used to simulate viscoelastic complex flows effectively.Moreover,the influence of Deborah number and viscosity ratio on polymeric stress was also investigated.展开更多
为了研究Mg_(97)Gd_(2)Y_(1)合金中β'相的粗化过程以及相关析出结构的形成和演变机制,使用原子分辨的高角度环形暗场-扫描透射电子显微镜(high angle annular dark field scanning transmission electron microscope,HAADF-STEM)...为了研究Mg_(97)Gd_(2)Y_(1)合金中β'相的粗化过程以及相关析出结构的形成和演变机制,使用原子分辨的高角度环形暗场-扫描透射电子显微镜(high angle annular dark field scanning transmission electron microscope,HAADF-STEM)成像技术表征了合金不同时效阶段形成的析出结构,并结合第一性原理计算的方法分析了它们的稳定性.结果表明,相关的β_(F)'、β_(M)和β″相主要在β'相粗化过程的早期形成,它们的形成与β'相相界面周围存在较高的错配应变场密切相关;随着β'相粗化过程的进行,β_(M)和β″相的尺寸和数量逐渐减少,而由β'与β_(F)'相交替组成的竹节状析出物增多,成为合金基体中主要的析出结构;当错配应变足够大时,β_(F)'相内部出现位错,β相在位错处可以形核,并逐渐长大成为基体中主要的平衡析出结构.展开更多
文摘Deterministic simulation approach was applied to simulating viscoelastic complex flows,in which,the SIMPLE algorithm based on collocated grid was used to solve the conservation equations on the macroscopic level and the spectral method was used to solve the Fokker-Planck equation on the mesoscopic level.Here,the transient 4∶1 planar contraction flow for dilute polymer solution was computed by using the coupled technique and the calculated polymeric stress distributions at steady state were identical with the results of continuum approach as well as the corresponding references.Therefore,the presented results indicated that the SIMPLE algorithm based on collocated grid coupled with the spectral method can be used to simulate viscoelastic complex flows effectively.Moreover,the influence of Deborah number and viscosity ratio on polymeric stress was also investigated.
文摘为了研究Mg_(97)Gd_(2)Y_(1)合金中β'相的粗化过程以及相关析出结构的形成和演变机制,使用原子分辨的高角度环形暗场-扫描透射电子显微镜(high angle annular dark field scanning transmission electron microscope,HAADF-STEM)成像技术表征了合金不同时效阶段形成的析出结构,并结合第一性原理计算的方法分析了它们的稳定性.结果表明,相关的β_(F)'、β_(M)和β″相主要在β'相粗化过程的早期形成,它们的形成与β'相相界面周围存在较高的错配应变场密切相关;随着β'相粗化过程的进行,β_(M)和β″相的尺寸和数量逐渐减少,而由β'与β_(F)'相交替组成的竹节状析出物增多,成为合金基体中主要的析出结构;当错配应变足够大时,β_(F)'相内部出现位错,β相在位错处可以形核,并逐渐长大成为基体中主要的平衡析出结构.
