**ABSTRACT**

The present investigation employed computational techniques to analyze the heat transfer and fluid flow properties of a Water/Cu nanofluid moving through a rectangular microchannel. The upper wall of the microchannel is thermally insulated, while the lower wall is equipped with a ribbed surface maintained at a greater temperature than the fluid entering the channel. The governing equations were discretized using the finite volume method and solved using the ANSYS-Fluent 16.0 Computational Fluid Dynamics soft-ware. The study investigated the influence of many parameters, such as the Reynolds number (20 ≤ Re ≤ 200), volume percentages of nanoparticles (1% ≤ φ ≤ 8%), and rib height. The numerical results demonstrate that when the height of the ribs rises (e = 20, e = 30, and e = 40 μm), the contact surface area between the ribs and the nanofluid similarly increases. As a result, the friction factor of the heated surface rises, regardless of whether the Reynolds numbers are low or high. Furthermore, numerical analysis suggest that the average friction factor diminishes as the Reynolds number rises for all rib heights. Ribs in the microchannel facilitate improved mixing, resulting in heightened heat transfer. The impact is intensified by augmenting the concentration of nanoparticles and the Reynolds numbers at all rib heights.

**KEYWORDS**

PAPER SUBMITTED: 2024-02-06

PAPER REVISED: 2024-03-04

PAPER ACCEPTED: 2024-04-15

PUBLISHED ONLINE: 2024-06-22

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