Thermo-fluidic characteristics of natural convection in honeycombs: The role of chimney enhancement

The natural convective heat transfer performance and thermo-fluidic characteristics of honeycombs with/without chimney extensions are numerically investigated. The present numerical simulations are validated by the purposely-designed experimental measurements on honeycombs with/without chimney. Good agreement between numerical simulation and experimental measurement is obtained. The influences of inclination angle and geometric parameters such as cell shape, streamwise and spanwise length are also numerically quantified. With the increment in inclination angle, the overall heat transfer rate decreases for the honeycombs with/without chimney. For honeycombs with the same void volume fraction but different cell shapes, there is little difference on the overall heat transfer rate. To enhance the natural convective heat transfer of honeycombs, these techniques including increasing the length of honeycomb in the streamwise/spanwise direction, increasing the thermal conductivity of hon-eycomb structure or adding a chimney extension may be helpful.