Investigation Of Gas Thermal Conductivity In Nanopore By Molecular Dynamics

Because of the special properties of the nano-materials, nano-materials are applied in many fields. Compared with traditional porous materials , nanoporous insulation materials has the characters of micro/nano-scaled heat transfer, which result in good insulation property. At present,using molecular dynamic method to calculate the thermal conductivity of materials is popular internationally. Equilibrium molecular dynamics and nonequilibrium molecular dynamics have been applied to calculate thermal conductivity and thermal properties of micro-scaled materials ,which mainly are solid films and fluids . By solving the motion equation of the particles with special potential function, molecular dynamics method can simulate the details of the action of particles in the system with time evolve and get physical parameters of the system. By numerical simulation of its thermal properties, we can analyze the relationship between the micro configuration and the macro thermal properties, and provide some theory suggests for optimizing design and production.In this thesis, according to the characters of configuration of nano-materials, we constitute two nanopore models. Equilibrium molecular dynamics method based on Lennard -Jones potential were performed to study the interaction of gas molecules. we calculate the gas thermal conductivity in the nanopore by programs.We get the results of how thermal conductivity of nanopore change with temperature and nonopore size,nanopore size ranging from 10 to 70 nm and temperature ranging from 250 K to 800 K. The results show that the gas thermal conductivity is smaller than that of bulk material. With the decrease of the size, temperature and pressure, the thermal conductivity decreases.