A Lattice Boltzmann Study of Nanofluid Flow and Conjugate Heat Transfer in Microchannels with Temperature Jump and Axial Conduction Phenomena

Abstract

This work introduces a refined numerical methodology based on the single-phase Lattice Boltzmann Method (LBM) to investigate nanofluid flow and conjugate heat transfer within a counter flow microchannel heat exchanger. The developed model incorporates critical microscale mechanisms, such as axial conduction through the solid walls and temperature discontinuities at the fluid-solid boundary. The velocity field is computed using a preconditioned version of the LBM, while the thermal field is solved using the standard formulation. A dedicated algorithm is implemented to accurately enforce the temperature jump condition at the interface. Model validation, performed through comparison with analytical solutions and benchmark data from the literature, confirms its robustness and accuracy. Simulations are carried out for nanoparticle volume fractions between0.001 and 0.05 and interfacial thermal contact coefficients varying from 0 to 0.1. Findings show that increasing nanoparticle concentration enhances the system’s thermal behavior, while the introduction of superhydrophobic surfaces does not compromise heat transfer and may, under certain conditions, improve the average Nusselt number particularly in high flow regimes. The interplay between wall thermal conductivity, particle concentration, and flow intensity is also explored in depth. Temperature distributions, isotherms, and Nusselt number trends confirm the effectiveness of the LBM in capturing microscale heat transfer dynamics. Additionally, reducing interfacial thermal resistance is shown to enhance convective heat transfer, albeit at the cost of greater thermal discontinuity at the wall interface.