A Novel Semi-empirical Model for Evaluating Thermal Performance of Porous Metallic Foam Heat Sinks

A novel semi-empirical model with an improved single blow method for exploring the heat transfer performance of porous aluminum-foam heat sinks in a channel has been successfully developed. The influencing parameters such as the steady-state air preheating temperature ratio, Reynolds number and medium porosity on local and average heat transfer behavior of porous aluminum-foam heat sinks in a channel are explored. The heat transfer enhancement of using a porous heat sink in a channel to a hollow channel is, $(Nu¯b)ss∕(Nu¯b)ε=1$⁠, much greater than unity and generally decrease with increasing $Re$⁠. Furthermore, two new correlations of $(Nu¯b)ss$ and $(Nu¯i)ss$ in terms of $ϴ,Re,Da,γ$ and $ε$ are proposed. As compared with the results evaluated by the transient liquid crystal method, the channel wall temperatures predicted by the present semi-empirical model have a more satisfactory agreement with the experimental data, especially for the cases with smaller porosities. The limitations with relevant error maps of using the transient liquid crystal method in porous aluminum foam channels are finally postulated.