Transport phenomena including the electromagnetic,concentration of ions,flow,and thermal fields in the electroslag remelting(ESR)process made of slag,electrode,air,mold,and melt pool are computed considering tertiary ...Transport phenomena including the electromagnetic,concentration of ions,flow,and thermal fields in the electroslag remelting(ESR)process made of slag,electrode,air,mold,and melt pool are computed considering tertiary current distribution.Nernst-Planck equations are solved in the bulk of slag,and faradaic reactions are regarded at the metal-slag interface.Aiming at exploring electrochemical effects on the behavior of the ESR process,the calculated field structures are compared with those obtained using the classical ohmic approach,namely,primary current distribution whereby variations in concentrations of ions and faradaic reactions are ignored.Also,the influence of the earth magnetic field on magnetohydrodynamics in the melt pool and slag is considered.The impact of the polarity of electrode,whether positive,also known as direct current reverse polarity(DCRP),or negative,as known as direct current straight polarity(DCSP),on the transport of oxygen to the ingot of ESR is investigated.The obtained modeling results enabled us to explain the experimental observation of higher oxygen content in DCSP than that of DCRP operated ESR process.展开更多
The cooling channel process is a rehocasting method by which the prematerial with globular microstructure can be produced to fit the thixocasting process.A three-phase model based on volume averaging approach is propo...The cooling channel process is a rehocasting method by which the prematerial with globular microstructure can be produced to fit the thixocasting process.A three-phase model based on volume averaging approach is proposed to simulate the cooling channel process of A356 Aluminum alloy.The three phases are liquid,solid and air respectively and treated as separated and interacting continua,sharing a single pressure field.The mass,momentum,enthalpy transport equations for each phase are solved.The developed model can predict the evolution of liquid,solid and air fraction as well as the distribution of grain density and grain size.The effect of pouring temperature on the grain density,grain size and solid fraction is analyzed in detail.展开更多
文摘Transport phenomena including the electromagnetic,concentration of ions,flow,and thermal fields in the electroslag remelting(ESR)process made of slag,electrode,air,mold,and melt pool are computed considering tertiary current distribution.Nernst-Planck equations are solved in the bulk of slag,and faradaic reactions are regarded at the metal-slag interface.Aiming at exploring electrochemical effects on the behavior of the ESR process,the calculated field structures are compared with those obtained using the classical ohmic approach,namely,primary current distribution whereby variations in concentrations of ions and faradaic reactions are ignored.Also,the influence of the earth magnetic field on magnetohydrodynamics in the melt pool and slag is considered.The impact of the polarity of electrode,whether positive,also known as direct current reverse polarity(DCRP),or negative,as known as direct current straight polarity(DCSP),on the transport of oxygen to the ingot of ESR is investigated.The obtained modeling results enabled us to explain the experimental observation of higher oxygen content in DCSP than that of DCRP operated ESR process.
文摘The cooling channel process is a rehocasting method by which the prematerial with globular microstructure can be produced to fit the thixocasting process.A three-phase model based on volume averaging approach is proposed to simulate the cooling channel process of A356 Aluminum alloy.The three phases are liquid,solid and air respectively and treated as separated and interacting continua,sharing a single pressure field.The mass,momentum,enthalpy transport equations for each phase are solved.The developed model can predict the evolution of liquid,solid and air fraction as well as the distribution of grain density and grain size.The effect of pouring temperature on the grain density,grain size and solid fraction is analyzed in detail.
