An X-lattice cored rectangular honeycomb with enhanced convective heat transfer performance

This paper proposes a new periodic cellular material (PCM) by integrating the X-lattice into a rectangular honeycomb. Convective heat transfer in this new PCM is explored. For a given Reynolds number, the overall Nusselt number of the new PCM is up to 360% and 55% higher than the parent honeycomb and X-lattice sandwich panel, respectively. The introduction of the honeycomb walls to the X-lattice sandwich panel enlarges or induces new separation vortices near the four corners of each rectangular passage, which weakens the tangential flow perpendicular to the mainstream; the no-slip honeycomb walls and the modification of the separation vortices change the counter-rotating vortex pair behind the ligaments, significantly reduce the bulk turbulent kinetic energy magnitude and limit the convective transport of the high turbulent kinetic energy to the endwalls, due to severe dissipation of the energy by the viscous sub-layer. Corresponding to the flow pattern variations, local heat transfer on the endwall and the X-lattice ligaments is deteriorated. However, the X-lattice induced spiral flow and secondary flows enhance the heat transfer on the honeycomb walls by approximately 230%. For a given pumping power, the new PCM exhibits up to 42% higher heat removal than the parent X-lattice sandwich.