Abstract:Closed-cell aluminum foam has incomparable advantages over other traditional materials for thermal insulation and heat preservation because of small thermal conductivity coefficient. Spherical bubble three-dimensional model of aluminum foam is built to deduce the relationship among pore wall thickness, porosity and average pore size. Non-uniform closed-cell foam aluminum model with different structural parameters and random pore distribution is established based on the relationship via C programming language. And the temperature distribution is analyzed with ANSYS software. Results indicate that thermal conductivity increases with the reducing of porosity. For the aluminum foam with the same porosity, different pore distributions result in different thermal conductivities. The temperature distribution in aluminum foam is non-uniform, which is closely related with the pore size and distribution. The pores which extend or distribute along the direction perpendicular to heat flow strengthen obstructive capability for heat flow. When pores connect along the direction perpendicular to heat flow, a “wall of high thermal resistance” appears to decline the thermal conductivity rapidly, which shows that only porosity cannot completely determine effective thermal conductivity of closed-cell aluminum foam.

Key words: closed-cell aluminum foam; thermal conductivity; porosity; pore distribution; temperature distribution