关键词: 格子Boltzmann方法;微通道;对流换热;表面形貌;分形理论

Abstract: To promote the application of microchannel cooling technology in aero engine and further improve the performance of the aero engine， the surface morphology of the actual processed object was obtained by scanning electron microscopy， roughness scanner and other methods. Combined with the fractal theory， four types of circular cross-section tube models were obtained， such as real tube， smooth tube， fractal interpolation tube and cantor set tube. The diameter range of the tubes was 100~400μm. The Lattice Boltzmann method was used for numerical simulation. Firstly， the correctness of the method was verified by comparison with the experimental results in the literature. Then， the convective heat transfer characteristics of air in these four types of circular cross-section microchannels were numerically simulated， and the Re range was 80~640. The results show that surface morphology is a factor that cannot be neglected in convective heat transfer in microchannels， the larger the relative roughness， the better the heat transfer， and the heat transfer performance of the real scanning tube is 2.22% higher than that of the smooth tube under the same conditions. The fractal theory can be used to construct the surface morphology of microchannels. However， the fractal interpolation model can more accurately reflect the actual shape than the Cantor set model under the same number of iterations. The heat transfer performance of the fractal interpolation model differs from the real scan topography by 0.03%， while the heat transfer performance of the Cantor set model differs from the real scan topography by 1.88%. In the microchannel， as the Reynolds number increases， Nu will no longer be a constant， but has an increasing trend.

Key words: Lattice Boltzmann method;Microchannel;Convective heat transfer;Surface topography;Fractal theory