Study On The Microscale Thermal Transfer Characteristic Of The Composite Material Based On Lattice Boltzmann Method

In the past two decades, as the development of semi-conductor technique, micro electro mechanical systems (MEMS) and nano electro mechanical systems (NEMS). The mechanics-thermal-electromagnetic behaviors of nano-devices or nano-structure have been paid more attention. Numbers of experiment indicated that the heat transfer is different from in macro scale when the characteristic dimension reduced to nano-microscale. The heat transfer characteristic of nano-microscale structures or nano-microscale devices become one of important topics in the design of MEMS and NEMS.Based on the Boltzmann transport theory and Lattice Boltzmann Method, firstly a two-dimensional nine-speed (D2Q9) lattice Boltzmann incompressible thermal model is introduced, and the isothermal, adiabatic, thermal contact resistance boundary condition are also introduced. Then a numerical code based on the lattice Boltzmann method is developed to quantitatively simulate the thermal conductive characteristics of the composite material considering contact thermal resistance with the different shape's inclusions. Heat transfer of composite materials under transverse harmonic magnetic field and electric field in the conductor are also discussed. With consideration of contact thermal resistance, the thermal conductive characteristics of the composite material with the different shape's inclusions are studied. Some results on the characteristics of heat transport characteristics, such as the temperature distribution in the structure at a time-point are presented respectively. The effective thermal conductivities for the composite material with the different shape's inclusions are obtained. Further Temperature distribution in the structure and the relationship between effective thermal conductivity and the size of structure, reflection coefficient, arealso studied.From above studies, we found that Lattice Boltzmann Method is a valid method for nano-microscale heat transfer. Thermal contact resistance and size effects are important factor for affecting effective thermal conductivity.