Effect of CuO Nanoparticle Size and Concentration on Thermal Enhancement in Shell-and-Tube Heat Exchangers

Akarken G., Cengiz U., Bektaş T. E.

Journal of Engineering Research and Applied Science, cilt.15, sa.1, ss.77-87, 2026 (Hakemli Dergi)

Özet

In this study, a custom-designed shell-and-tube heat exchanger (STHE) system was developed and initially modeled via simulation under nanoparticle-free conditions to establish baseline heat transfer parameters. Flow regimes were identified through Reynolds number calculations at different flow rates, and the corresponding convective heat transfer coefficients (hi, ho), overall heat transfer coefficient (U), and heat duty (Q) values were determined. Following simulation calibration, experimental investigations were conducted using CuO–water nanofluids with two distinct particle sizes (38 nm and 20 µm) and three concentrations (0.25%, 0.5%, and 0.75%). The impact of these parameters on the thermal performance of the STHE was evaluated under varying inlet temperature conditions. Experimental results revealed that cold fluid outlet temperatures increased significantly with the addition of nanoparticles, while hot fluid outlet temperatures decreased, indicating enhanced heat absorption. For 38 nm particles, the cold-side enhancement (ΔT) ranged from 1.0 °C to 2.2 °C, corresponding to approximately 5–12% improvement relative to the baseline. In contrast, 20 µm particles exhibited ΔT values of 1.5–2.7 °C, equating to a 6–14% increase depending on concentration and inlet temperature. The most pronounced enhancements were observed at 0.5% and 0.75% concentrations, particularly at higher temperature gradients, demonstrating that both particle size and concentration play critical roles in nanofluid-mediated heat transfer enhancement.