介孔材料MCM-41的导热研究

Thermal conductivity of mesoporous material MCM-41

文章根据二氧化硅介孔材料MCM-41纳米孔结构特点,首先建立和验证了纳米结构单元模型,然后使用平衡分子动力学方法模拟了孔壁热导率;接着耦合孔隙内气体导热,开展了一维传热分析,最终提炼出MCM-41的有效热导率表达式;并对壁厚、孔径和孔隙率对热导率的影响进行了分析.研究结果表明,MCM-41具有良好的绝热性能,其有效热导率随孔隙率增大近似呈线性减小,且表现出各向异性;导热性能沿孔道长度方向表现出准一维特性.

In this paper,the mesoporous structural unit of MCM-41 is established first and the equilibrium molecular dynamics （EMD） numerical simulation is performed to obtain the shell thermal conductivity of MCM-41.Then,based on one-dimensional heat transfer analysis,the analytical expression for effective thermal conductivity of MCM-41 is obtained by coupling heat conduction in air-filled nano-pores and that in the shell.The effects of wall thickness,pore size and porosity on the thermal conductivities of the MCM-41 are further analyzed.It turns out that MCM-41 possesses good thermal insulation and the decrease of effective thermal conductivity is closely linear as porosity increases.Furthermore,the thermal conductivity shows that it is obviously anisotropic and its largest value is along the length of the pores,and that it has the quasi-one-dimensional characteristic.