Muthanna Journal of Engineering and Technology
Volume (14), Issue (3), Year (2026), Pages (91-105)
DOI:10.52113/3/eng/mjet/2026-14-03-/92-105
Research Article By:
Amal Oliwie
Corresponding author E-mail: amalhusseinaliwie@wrec.uoqasim.edu.iq
ABSTRACT
Heat transfer enhancement in double heat exchangers contains to be a significant challenge in thermal engineering. This paper investigates how varying the number of dimples (4, 6, and 8) in cross-sectional dimpled channels influences forced convection phenomena and the friction factor. A numerical study was conducted featuring a three-dimensional analysis of the friction factor, enhanced heat transfer, and thermal performance criteria (PEC) within a dimpled channel with water flow. To simulate the flow within a circular channel, a commercial software application, ANSYS FLUENT, was utilized. The simulation employed governing equations, include continuity, momentum, and energy equations, as well as the RNG k-ε turbulence model. This model was used to assess the impact of varying the number of dimples on turbulent flow and heat transfer enhancement. The research focused on Reynolds number (Re) range of 2500 to 12000, especially targeting turbulent flow. The findings indicate that the existence of dimples on the channel wall significantly influences both heat transfer and friction factor when compared to a smooth channel. Numerical analysis notified that the Nu for the three cases of dimples in cross-sectional area (4,6, and 8) was 30.2% ,41.3% and 49.06% larger respectively, than that of the conventical channel. Additionally, the channel with 8-dimples exhibited the highest (f) in comparison to the other configurations. The design featuring 4-dimples in cross sectional area achieved the highest value of the performance evaluation criteria (PEC) across all Re values. These findings offer significant scientific insights for the optimizing thermo-hydraulic performance through varying dimple numbers, providing practical design guidelines for advanced and energy-efficient heat exchange systems.
Keywords: Heat transfer enhancement, dimpled channel, turbulent flow, pressure drop, thermal performance criteria.