微波烧结陶瓷热均匀性的三维模拟研究  

Numerical simulation of thermal uniformity of microwave sintering ceramics

作　　者：谢蒙优 石建军[1] 陈国平[1] 曾雪涵 Xie Mengyou;Shi Jianjun;Chen Guoping;Zeng Xuehan(School of Civil Engineering and Architecture,Southwest University of Science and Technology,621010,Mianyang,China)

机构地区：[1]西南科技大学土木工程与建筑学院,绵阳621010

出　　处：《应用力学学报》2020年第4期1663-1669,I0019,I0020,共9页Chinese Journal of Applied Mechanics

基　　金：四川省科技厅项目(2020JDTD0021,2020YFG0183,2019YFG0254);结冰与防除冰重点实验室开放课题资助(IADL20190402)。

摘　　要：利用有限元软件COMSOLMultiphysics,考虑了温度和孔隙率敏感的电磁学、热力学和力学的材料性质,基于烧结的连续介质力学建立了耦合电磁-热-力的多物理场、单模微波腔内烧结陶瓷材料的三维模型,实现了整个微波烧结过程的数值模拟,并与实验数据进行了对比,验证了有限元模型的合理性。通过该模拟研究了在烧结过程中材料内的电场、温度和致密化的分布和变化。结果表明,在高介电损耗材料基座作用下,低损耗材料迅速升温,来自微波的电能转换成热量,并观察到显著的介电耦合现象。微波烧结陶瓷材料的结果显示出了加热行为对电磁场分布、材料的介电性能、热力学性能和温度分布的复杂依赖性。试样剖面的温度和温度梯度演变图显示出微波烧结过程中不规则的温度分布情况。这种不均匀性主要是由粉体材料不均匀的电特性和电场分布决定的。本文建立的COV(变异系数)误差图显示出粉体材料微波烧结过程中随温度增加而产生的热异质性.A three-dimensional model built through the finite element software COMSOL Multiphysics is used to investigate the hybrid microwave sintering process. The temperature and porosity dependence of electromagnetic, thermodynamic and mechanical material properties have been considered. Numerical simulation of the entire microwave sintering process in the single-mode microwave cavity has been realized, and the numerical data is compared with experimental data, which proves the rationality of the finite element model. In this paper, the sintering theory of continuum is used to study three principal aspects: the distribution of electric field, temperature variation and densification of material. As a result, a significant "permittivity-temperature" coupling is observed under the effect of susceptor in high dielectric-loss materials, the electrical energy from microwave is converted into heat. The results of the heating behavior of the ceramic material show the complex dependence of the electromagnetic field, the dielectric properties, thermodynamic properties and temperature distribution of the material. The temperature and temperature gradient evolution graph of the sample inner section show the irregular temperature distribution during the microwave sintering process. The COV error chart established shows the thermal heterogeneity of powder materials with increasing temperature during microwave sintering.

关 键 词：微波烧结 多孔介质 数值模拟 热均匀性 

分 类 号：TH164[机械工程—机械制造及自动化]