Numerical Investigation on Heat Transfer and Pressure Drop in Silver/Water Nanofluids Flowing Through Tubes with Variable Expansion–Contraction Ratios

Enio Pedone Bandarra Filho (), Erick Oliveira do Nascimento, Muhammad Farooq and Luben Cabezas-Gómez
Additional contact information
Enio Pedone Bandarra Filho: Department of Mechanical Engineering, College of Engineering, Prince Mohammad Bin Fahd University (PMU), Al Khobar 31952, Saudi Arabia
Erick Oliveira do Nascimento: School of Mechanical Engineering, Federal University of Uberlandia (UFU), Av. Joao Naves de Ávila, 2121, Uberlandia 38400-902, MG, Brazil
Muhammad Farooq: Department of Mechanical Engineering, College of Engineering, Prince Mohammad Bin Fahd University (PMU), Al Khobar 31952, Saudi Arabia
Luben Cabezas-Gómez: Heat Transfer Research Group, São Carlos School of Engineering, University of São Paulo, Avenida Trabalhador São-Carlense 400, Parque Arnold Schimidt, CEP, São Carlos 13566-590, SP, Brazil

Energies, 2025, vol. 18, issue 1, 1-27

Abstract: This study presents a numerical investigation on the heat transfer and pressure drop characteristics of silver/water nanofluids (0.1–0.5 vol.%) flowing in tubes with four distinct expansion–contraction ratios (ECR = 1.25, 1.50, 1.75, and 2). Additionally, the impact of the distance between expansion and contraction (DEC) within the tubes was examined. The analysis was conducted under turbulent flow conditions and three-dimensional thermal convection in tubes subjected to a constant heat flux of 20 kW/m 2 , with the inlet Reynolds number maintained at approximately 20,000. The nanofluids were considered as single-phase and modeled in the Ansys Fluent 16 software through the finite volume method, and the equations were discretized through the second-order upwind scheme. The nanofluids demonstrated significant potential in enhancing thermal performance, particularly in tubes where the convective heat transfer coefficient was affected by abrupt expansion–contraction ratio (ECR). A maximum increase of up to 24.90% in the average convective heat transfer coefficient compared to the base fluid was observed. Exergy efficiency showed a tendency to increase by up to 29.97% with the use of nanofluids. The findings indicate that the convective heat transfer coefficient can both increase and decrease with the expansion–contraction ratio (ECR) of the tube, as can the pressure drop. Consequently, the application of this passive technique, incorporating silver/water nanofluids, holds promise for use in cooling systems, nuclear reactors, and other similar applications, provided they are meticulously designed.

Keywords: computational fluid dynamics; heat transfer; expansion and contraction; silver nanofluid; exergy efficiency (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2025
References: View references in EconPapers View complete reference list from CitEc
Citations:

Downloads: (external link)
https://www.mdpi.com/1996-1073/18/1/161/pdf (application/pdf)
https://www.mdpi.com/1996-1073/18/1/161/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jeners:v:18:y:2025:i:1:p:161-:d:1559361

Access Statistics for this article

Energies is currently edited by Ms. Agatha Cao

More articles in Energies from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().