Impact of nanofluids and porous structures on the thermal efficiency of wavy channel heat exchanger

Mezaache A., Mebarek-Oudinal F., Vaidya H., Ramesh K.

INTERNATIONAL JOURNAL OF THERMAL SCIENCES, vol.210, 2025 (SCI-Expanded, Scopus)

Abstract

Wavy walls, porous metal structures, and nanofluid coupling are still essential scientific research issues. This process is primarily used as a passive technique to increase the performance and efficiency of heat sinks and heat exchanger systems. The present study investigates the thermal characteristics of a nanofluid flow inside a wavy channel partially filled with porous material. Two distinct porous material structures applied in thermal engineering, including packed granular and foam porous material, are simulated and compared. The numerical results are validated with previous works. The coupled effects of porous layer thickness (delta) and flow Reynolds number (Re) on the Nusselt number, entropy generation, friction factor, and performance evaluation criteria are analyzed. It is shown that the porous insertion thickness and porous material structure significantly affect the hydrodynamical and thermal performance of the porous channel. This effect is more important when using packed granular material than foam. As an illustration, for Re = 400, in the range delta [0.2-0.5], comparatively to the clear channel, for packed granular material, Nusselt number increase is [43.04%-134.64 %], and entropy is [97.68-437.06 %]. This increase is less critical for foam metal than packed granular metal, either [36.19%- 94.53 %] for Nusselt number and [70.83%-197.90 %] for entropy. Analyzing the coupled effect between the flow Reynolds number, the porous layer thickness, and the porous material structure, significant improvement in heat transfer and thermal efficiency in wavy channels can be achieved.