Thermal analysis of a non-homogeneous insulating panel

This article describes heat flow meter measurements and transient thermal modelling (using ANSYS) of a webbed, hollow-cored panel located between silicone sponge buffer materials chosen to provide boundary conditions comparable to standard surface coefficients. Panel surface temperatures were also measured at eight locations to record the thermal measurement as a temperature step function following isothermal stabilization. An uninsulated configuration was studied as well as cases with different levels of bulk insulation filling the panel cores. Measured and modelled temperature-time plots agreed well after corrections for web and airspace thermal conductivity. Modelled spatial variation in heat flow exceeded 200% for one insulated case but was only about 2% for the uninsulated panel. Modelled values for heat flux and overall thermal resistance agreed well with standard analytical calculations. However, heat flows indicated by the apparatus were consistently higher than the modelled and calculated values by up to 8%, expected to be due at least partially to specimen non-homogeneity. Nevertheless, results suggest a useful role for the apparatus in providing temperature measurement under controlled conditions, helping to validate thermal modelling as a potential alternative to hot box measurement for non-homogeneous assemblies.