Conjugate RANS and DNS Simulations of Highly Rough Cooling Channels

With the growing adoption of additive manufacturing for liquid rocket engine thrust chambers, accurate heat transfer modeling in high-roughness cooling channels has become increasingly important. Turbulence models for rough-wall channels are typically validated within roughness ranges much smaller than those produced by additive manufacturing. Although operating with high roughness can be acceptable due to the balance between increased friction and heat transfer, it is crucial to account for the differing behaviors of momentum and heat exchange models at high roughness levels to achieve realistic predictions of skin friction and heat transfer. To assess the performance of current RANS models and identify potential improvements, this study compares RANS and DNS simulations. A computational analysis of conjugate heat transfer in a square cooling channel is conducted for various fluid-solid thermal conductivity ratios.