Computational Analysis of Mixed Convection in Rotating Cavities: Thermal and Rheological Behavior of Power‐Law Fluids

This study investigates the mixed convection heat transfer of non‐Newtonian power‐law fluids in a rotating cylindrical enclosure containing a stationary triangular block, considering various fin configurations. The outer cylinder rotates at a constant angular velocity and is maintained at a lower temperature, while the inner block remains fixed and heated. Key parameters, such as rotational speed ( Re ), thermal buoyancy ( Ri ), number of fins, and the power‐law index ( n ), were varied to evaluate their effects on flow dynamics and thermal performance. Numerical simulations were performed using the finite volume method, and the fluid's rheology was modeled using Ostwald's law. The results show that fins do not always enhance performance in rotating mixed convection systems. The finless triangular block yields up to 50% higher Nusselt numbers compared with finned cases, due to reduced obstruction and stronger recirculation. Entropy generation analysis reveals a trade‐off: shear‐thinning fluids ( n = 0.6) and finned blocks enhance heat transfer but increase irreversibility, whereas shear‐thickening fluids ( n = 1.6) minimize entropy generation at the expense of weaker convection.