Connecting immersed boundary method with heat transfer for simulations of mechanical metamaterials

In the energy or foundry industry, mechanical metamaterials have become increasingly popular since they can be designed to have unique heat transfer properties. These properties are granted by the metamaterial inner structure, which can be further optimized for a specific application. In this contribution, we present a numerical solver usable for such optimization. To allow for an easy change of the metamaterial inner structure, the solver is based on our custom variant of the immersed boundary method. The solver also accounts for turbulent flow via Reynolds-averaged simulation approach and includes equations for heat transfer. First, to assess the solver, a series of simple benchmark cases was prepared to study its sensitivity to the flow Reynolds number and to compare the results with standard OpenFOAM solvers. Then, an exemplary metamaterial simulation was prepared to test the solver capabilities in more realistic scenarios, mainly evaluating the effect of mesh resolution and the amount of material bulk. The latter tests showed that the solver does not have particular problems with computations of the flow fields. For the temperature field, the differences to standard solvers are bigger, but the trends in heat transfer properties are kept well.