Modeling of conjugate forced convection using effective boundary conditions: From plane channel to the human nose

Accurate analysis of conjugate heat transfer (CHT) is of primary importance in many engineering applications and biological flows where it is crucial to implement a reliable model that couples thermal conduction in the solid boundary with convection in the fluid. CHT simulations entail higher computational costs to well resolve the smooth/rough solid layers and to generate high-quality meshes for complex finite-thickness wall geometries. This work adopts upscaled boundary conditions capable of modeling the heat transfer at a fraction of the cost of the full conjugate-forced-convection analysis. The effective velocity and temperature conditions are applied to pressure-driven, developing flows through ducts with different types of wall roughness down to the smooth limit. The results are compared against fully resolving CHT simulations, and the good agreement demonstrates suitability of the macroscopic approach as a cheaper alternative. The model is finally applied to the flow within the human nose, where CHT is mandatory because of the physiological importance of thermal exchange processes. Despite the simplifying assumptions made to the physics in this case, the results obtained are fairly encouraging for future use of the model, possibly with relevant adjustments and extensions, in typical biomedical contributions.