Recent research has extensively investigated the rheological and thermal behaviors of nanofluids. The present work provides a detailed numerical investigation of heat transfer and pressure drop characteristics in sinusoidal and straight tubes using two types of nanofluids: water-based and ethylene glycol-water-based suspensions with nanoparticles. The simulations were conducted under laminar flow conditions using ANSYS CFX software with a constant and uniform heat flux boundary condition. Different nanoparticle sizes and concentrations were examined to evaluate their impact on heat transfer enhancement.
The research gap addressed in this work lies in the limited number of studies that have simultaneously integrated sinusoidal tube geometry and nanofluid properties to enhance heat exchanger performance. This paper bridges that gap by numerically comparing the heat transfer characteristics of sinusoidal tubes against traditional straight tubes under identical operating conditions.

The results demonstrate that increasing Reynolds number and nanoparticle concentration significantly enhances the heat transfer coefficient. Overall, sinusoidal tubes combined with nanofluids achieved up to 25–30% improvement in the Nusselt number compared to straight tubes, highlighting their potential for compact and energy-efficient heat exchangers.

The research gap lies in the limited studies that simultaneously integrate sinusoidal tube geometry and nanofluid properties to enhance heat exchanger performance.

The results clearly demonstrate that increasing the Reynolds number and nanoparticle volume concentration significantly enhances the heat transfer coefficient. Overall, sinusoidal tubes combined with nanofluids provided up to 25% improvement in Nusselt number compared to straight tubes, highlighting their potential for compact and efficient heat exchangers.

Sinusoidal tubes, Reynolds number, Heat transfer, Nanofluid

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