电场活化烧结温度场的数值模拟

Numerical Simulation of Temperature Distribution during Electric Field Activated Sintering

根据电磁理论及微／纳米尺度热波模型,建立了粉末电场活化烧结过程中温度场-电场耦合控制方程,利用有限元方法对纯钛粉试样电场活化烧结中的热电效应进行了数值模拟,得到电场活化烧结过程中模冲、阴模及试样内的电流密度、焦耳热及温度场分布。结果表明:电场活化烧结过程中存在较大的升温速率和径向温度梯度,电流密度的分布对焦耳热、温度场的分布有较大影响。实测温度值与有限元计算值变化趋势基本一致。

A basic model for electric field activated sintering was presented by electromagnet theory, and the equations coupling electric field and temperature field were set up based on the theories of microscale heat transfer and electromagnetics. The thermoelectric phenomena in specimen, female die, punch during electric field activated sintering were simulated using the software FEMLAB. Numerical calculations were based on finite element analysis and the coupling of PDEs and electromagnetic modules. And the current density, resistance heating and temperature distributions in the specimen, female die, punch and their evolution during electric field sintering were obtained. The high heating rate and the obvious effect of current density on resistance heating, temperature distribution in specimen, female die, punch were found. The temperature of lower punch was measured using a thermocouple. The experimental results are in good agreement with those resulted from FEM, which indicates that FEM is valid analysis method to simulate temperature field in electric field activated sintering.