Forced convection in metallic honeycomb structures

The heat transfer and pressure drop characteristics of sandwiched metallic honeycomb structures, with one face-sheet heated by constant heat flux and cooled by forced air convection, have been investigated both experimentally and numerically. Six test samples, made of two materials with different thermal conductivities (16.2 W/(mK) for stainless steel and 401 W/(mK) for pure copper), were evaluated. The effect of cell shapes was also explored using samples with square, diamond, trapezoidal and hexagonal shapes. Good agreements between experimental and numerical results were obtained for both the friction factor (pressure drop) and heat transfer rate. The results show that the overall pressure drop is correlated with surface area density and cell shape, whereas the overall heat transfer rate is a function of surface area density, cell shape, the ratio t/H, and the thermal conductivity of the solid material. Comparisons with other heat sink media have also been made. They indicate that the metallic honeycomb structures investigated are excellent candidates for heat sink applications.