Equations for numerical simulation of channel segregation based on a model of continuum ap- proach to porous medium were advanced.In order to solve the non-linear computation prob- lem caused by the interactions betwe...Equations for numerical simulation of channel segregation based on a model of continuum ap- proach to porous medium were advanced.In order to solve the non-linear computation prob- lem caused by the interactions between unknown variables in the equations,the trial-and-er- ror method is used.The computation results showed that the radial back-flow due to natural convection in mushy zone indeed exists in A1-4.5wt-%Cu alloy ingot under the condition of low cooling rate,and that the numerical simulation of channel segregation is applicable due to the coincidence of calculated concentration with the experimental values.展开更多
Macrosegregation in Fe-0.8 wt pct C alloy solidifying with equiaxed morphology was numerically simulated. Based on a two-phase volumetric averaging approach, heat transfer, melt convection, composition distribution, n...Macrosegregation in Fe-0.8 wt pct C alloy solidifying with equiaxed morphology was numerically simulated. Based on a two-phase volumetric averaging approach, heat transfer, melt convection, composition distribution, nucleation and grain evolution on the system scale were described. A weak-coupling numerical procedure was designed to solve conservation equations. Simulations were conducted to study the effects of cooling rate and nuclei density on the macrosegregation pattern. The relative infliJence of thermal buoyancy- and solutal buoyancy-induced flows on macrosegregation was identified. Calculated results indicate that a higher cooling rate establishes a more homogeneous composition. More uniform solute distributions are formed with increasing nuclei density. In addition, it is noted that the direction of channel segregates depends on the relative strength of thermal and solutal buoyancy forces.展开更多
By means of numerical simulation. the in fluence of gravity on fluid flow,patterns has been simulated.The result shows that with the increase of inclined angle,the velocity of fluid flow decreases and the isotherms be...By means of numerical simulation. the in fluence of gravity on fluid flow,patterns has been simulated.The result shows that with the increase of inclined angle,the velocity of fluid flow decreases and the isotherms become flatter,which suppresses the evolution of channel segregation.展开更多
文摘Equations for numerical simulation of channel segregation based on a model of continuum ap- proach to porous medium were advanced.In order to solve the non-linear computation prob- lem caused by the interactions between unknown variables in the equations,the trial-and-er- ror method is used.The computation results showed that the radial back-flow due to natural convection in mushy zone indeed exists in A1-4.5wt-%Cu alloy ingot under the condition of low cooling rate,and that the numerical simulation of channel segregation is applicable due to the coincidence of calculated concentration with the experimental values.
基金support from the Innovative Scientific-Research Project of Institute of Metal Research,CAS under grant No.KGCXZ-YW-206the Post-Doctor Foundation for China undergrant No.20080431162the Foundation of Harbin University of Science and Technology,China under grant No.20081526
文摘Macrosegregation in Fe-0.8 wt pct C alloy solidifying with equiaxed morphology was numerically simulated. Based on a two-phase volumetric averaging approach, heat transfer, melt convection, composition distribution, nucleation and grain evolution on the system scale were described. A weak-coupling numerical procedure was designed to solve conservation equations. Simulations were conducted to study the effects of cooling rate and nuclei density on the macrosegregation pattern. The relative infliJence of thermal buoyancy- and solutal buoyancy-induced flows on macrosegregation was identified. Calculated results indicate that a higher cooling rate establishes a more homogeneous composition. More uniform solute distributions are formed with increasing nuclei density. In addition, it is noted that the direction of channel segregates depends on the relative strength of thermal and solutal buoyancy forces.
文摘By means of numerical simulation. the in fluence of gravity on fluid flow,patterns has been simulated.The result shows that with the increase of inclined angle,the velocity of fluid flow decreases and the isotherms become flatter,which suppresses the evolution of channel segregation.
