Experimental Characterization of Thermal and Flow Behavior of Nanofluids with Varying Particle Shapes in Microchannel

Authors

Shaheed Mahdi Talib, General Directorate for Vocational Education, Ministry of Education, 56001 Karbala, Iraq AND College of Mechanical Engineering, University of Technology-Iraq, Alsina’a Street, 10066 Baghdad, IraqFollow
Ekhlas M Fayyadh, College of Mechanical Engineering, University of Technology-Iraq, Alsina’a Street, 10066 Baghdad, Iraq
Moayed R Hasan, College of Mechanical Engineering, University of Technology-Iraq, Alsina’a Street, 10066 Baghdad, Iraq

Abstract

This study experimentally investigates the thermal and hydraulic behavior of mono nanofluids in a single rectangular copper microchannel under single-phase forced convection. Experiments were conducted within a Reynolds number range of 165–2550, at an inlet temperature of 30 °C, and under an applied heat flux of 60 kW/m2. Deionized water was used as the reference fluid, while silver (Ag), graphene nanoplatelets (GNP), and multi-walled carbon nanotubes (MWCNT) were individually tested at a fixed volume concentration of 0.01%. The hydraulic diameter of the channel was 0.42 mm. The results demonstrate that all nanofluids increase the Fanning friction factor compared with deionized water, with the highest increase observed for GNP-based nanofluids (35.3%). Concurrently, heat transfer was significantly enhanced, as reflected in the average Nusselt number, with GNPs nanofluids showing the maximum improvement of 19.55%. The thermal performance factor confirmed that GNP nanofluids achieved the most favorable balance between enhanced heat transfer and hydraulic penalties, reaching a peak value of 1.14 at Reynolds numbers ranging from 200 to 500. By contrast, MWCNT and Ag nanofluids displayed moderate and limited improvements, respectively. The superior behavior of GNP nanofluids is attributed to their platelet morphology, high thermal conductivity, and strong particle–fluid interactions, which collectively intensify micro-convection and disrupt the thermal boundary layer. These mechanisms are consistent with previous findings and highlight the decisive influence of nanoparticle shape in governing microscale heat transfer performance. These findings provide new insight into how nanoparticle morphology governs microscale heat transfer, offering guidance for the design of efficient thermal management systems.

Recommended Citation

Talib, Shaheed Mahdi; Fayyadh, Ekhlas M; and Hasan, Moayed R (2026) "Experimental Characterization of Thermal and Flow Behavior of Nanofluids with Varying Particle Shapes in Microchannel," Engineering and Technology Journal: Vol. 44: Iss. 1, Article 9.