Utilization of thermally driven flows in the gap between periodically structured surfaces has been studied in the previous works. Donkov et al. [1] considered a ratchet channel with the temperature gradient applied between the opposing walls. Mixed diffuse and specular reflection boundary conditions were applied to the ratchet surface. They showed that flow could be induced in the gap between the surfaces. Shahabi et. al [2] investigated the physical mechanisms of the flow field and studied the effect of geometrical parameters in ratchet channel with diffuse and specular walls. They showed that suitable fin structures need to break the reflection symmetry and a purely geometrical symmetry breaking based on diffusively reflecting walls is not sufficient. Chen et al. [3] analyzed a novel configuration consisting of two facing isothermal ratchet surfaces at different temperatures using DSMC method and studied the effect of accommodation coefficient and miss-alignment distance.

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