Enhanced heat transfer in a pyramidal lattice sandwich panel by introducing pin-fins/protrusions/dimples

Three different heat transfer augmentation techniques namely pin-fins, protrusions and dimples applied to the substrate of a pyramidal sandwich panel are investigated. The flow and heat transfer characteristics of the three modified panels are numerically analyzed and the results are compared with those of the base pyramidal sandwich panel with no surface modification. The heat transfer augmentation techniques applied here change the fluid flow pattern and accelerate the flow adjacent to the substrate leading to higher heat transfer rates compared to the base case. At a fixed Reynolds number, the introduced pin-fins and protrusions enhance the overall Nusselt number by 11.4%-13.3% and 7.2%-7.6%, respectively, while the dimples slightly enhance the overall Nusselt number by 1.8%-3.1% compared to the base pyramidal sandwich panel. All of these surface modification techniques increase the pressure drop. The goodness factor for the four cases are also presented.