Multi-objective optimization of heat transfer mechanisms of microcellular polymeric foams from thermal-insulation point of view

In this study, a comprehensive investigation of heat transfer mechanisms of polymeric foams is performed using response surface methodology (RSM). Foam density, cell size and strut fraction are selected as variable parameters. A regression model is obtained to predict the overall thermal conductivity using analysis of variance (ANOVA) tool of RSM. The results indicate that this regression model with R-2 = 95.22% and having an error smaller than 4% has an appropriate performance to estimate the overall thermal conductivity. Foam density is the most effective parameter on the overall thermal conductivity with contribution of 69.8%, as ANOVA results show. Reduction of foam density and cell size leads to decreasing the thermal conductivity while it is also decreased by increasing the strut fraction. It is reported for the first time that the cell walls are dominant components in comparison to struts in heat transfer mechanism by solid phase. On the other hand, it is discovered that the strut component is the predominant part in absorption phenomenon. The overall thermal conductivity is 23.69 mW/mK at the optimum condition (i.e. foam density of 25 kg.m(-3), cell size of 1 mu m and strut fraction of 0.2 in the studied range) using multi-objective optimization tool of RSM.