This study experimentally investigates the thermal performance, fluid‐flow behavior, and economic feasibility of hybrid nanofluids ( and ) at 0.01–0.03 vol.% concentrations in a rectangular slab multichannel microchannel (RSMC) system with external cylindrical inserts (ECI). Experiments were conducted under flow rates of 9–375 mL/min in multiple microchannel (MC) configurations (MC‐06, MC‐12, and MC‐18). Results reveal that heat transfer increases with increasing flow rate, achieving a maximum at MC‐18 under turbulent conditions, with an enhancement of 60.49% and 11.39% compared to MC‐06 and MC‐12, respectively. Nanofluids with higher thermal conductivity (NF4, 0.67006 W/m‐K) achieved maximum improvement in performance (42.91%), thermal attributes (39.35%), and fluid flow attributes (30.89%) over the base fluid . Economic analysis indicates that higher flow rates and more channels increase pressure drop (Δ P ), pumping power, and cost, with the maximum (1177.3 W at Rs. 10.419/‐) observed for MC‐18 in turbulent flow. However, optimum cost‐effectiveness was attained at 9 ml/min, MC‐06, with high‐conductivity nanofluids (Rs. 0.00165/‐) under laminar flow. Comparative modeling showed computational fluid dynamics (CFD) and artificial neural network (ANN) provide superior predictive accuracy for thermal and fluid‐flow performance, while regression and ANN are more effective for economic analysis.
Kaushik et al. (Wed,) studied this question.