Pore-scale conjugate heat transfer of nanofluids within fibrous medium with a double MRT lattice Boltzmann model

The conjugate heat transfer of nanofluids within fibrous medium is explored at pore scales. To handle the heat flux discontinuities neighboring the complex interfaces, the correction terms are projected into the thermal multi-relaxation-time (MRT) lattice Boltzmann (LB) scheme which offer an effective and reliable approach to explore conjugate heat transfer dynamics. A random-walk-based stochastic model is presented to generate the fibrous medium made up of interconnected bending fibers. For conjugate heat transfer without convective flow, the steady-state temperature profiles are found independent to the fiber-to-fluid thermal conductivity ratio. Whereas for conjugate heat transfer with convective flow, heat transfer is enhanced with large fiber-to-fluid thermal conductivity ratios. In addition, with the convective flow with high Reynolds numbers, the resulting temperatures for varied fiber-to-fluid thermal conductivity ratios are considerable decreased which indicate high Reynolds numbers dominate the heat transfer process. The 3D pore-scale temperature distributions with varied thermal parameters are provided which demonstrate the capability of present conjugate thermal LB model.