Numerical Simulation Of Adhesive Composite Thermal Conductivity

With the heat radiation problem of electronic productis becoming more and more serious, adhesive composite materials with excellent heat conducting performance has become a research hotspot. In this paper,VC++, ANSYS and MATLAB programming jointly designed a parameter finite element analysis method to achieve the numerical simulation of adhesive composite thermal conductivity. Taking the AlN/EP heat adhesive composite as the research example, the reliability of this method is verified by comparing simulated and experimental values of the thermal conductivity of the composite material. In addition, the effect of filler particle spatial distribution, particle size, ratio of different particle size and particle shape on the thermal conductivity of adhesive composite materials was explored with the aid of finite element analysis method. The main results obtained are listed as follow:There are three kinds of particle space, namely the non-uniform distribution, random distribution and uniform distribution. the non-uniform distribution of particles in the system is the easiest to assemble to form the thermal network chain, so it has the maximal effect on the thermal conductivity of the filling system. Other spatial distribution system has little effect on the thermal conductivity of the filling system because they can not form an effective thermal path. Thus, the uneven distribution of the filler particles is the effective method to improve the thermal conductivity of the system.Choosing different particles which have four diameters 10μm, 40μm, 70μm and 100μm of AlN particles filled epoxy resin matrix to explore the influence on the thermal conductivity of the composites. The simulation results show that, when the particle size within a certain range(10μ m~40μ m), the larger the particle size is, the greater the thermal conductivity of the filling system is. But when the particle size is greater than this range(40 μ m), the influence of the filling system on thermal performance by the size of diameter is not greater as more. So selecting the appropriate size of the particles is an effective way to improve the thermal conductivity of the system.When the combination of particle is 40μ m/10μ m, small particles could fill in the gap between the large particles, which make the dispersing large particles connect together to form a thermal network chain make the thermal ratio of the mixing system higher than the single-particle-filled systems. When the ratio of both particle size achieve optimum, the thermal conductivity of the filler system is greatest. Comparing the effect of two difference ratio of partials(40μ m/10μ m and100μ m/10μ m), we found that the difference between two particles is, the greater improvement in the thermal properties of the system.By comparing the heat conductivity of three thermally conductive particles as spherical, ellipsoidal and whisker-shaped, we found that particle shape has little effect on the thermal conductivity of the system when the filling of the particle is lower. But with the amount of the filling increase, whisker-shaped particles can rapidly improve the thermal conductivity of the filling system, ellipsoidal particles followed, and the spherical particles is slowest. The difference between the thermal conductivity of this three filling system is growing, especially in the whisker-shaped particles and spherical particles filling system. Accordingly, slender particles is easy to establish connection with identical particles, forming heat conduction net chain to improve the thermal conductivity.