Abstract
The enhancement of heat transfer plays a vital role in developing efficient thermal systems in industrial applications such as various cooling device, gas turbines, heat exchangers, food processing, and the chemical industry. Surface modifications, such as ribs and dimples, have gained considerable attention due to their simplicity, effectiveness, and adaptability across various applications. The surface modification enhances heat transfer. This review provides a comprehensive analysis of past and present studies focused on heat transfer enhancement of extended surfaces of rib and dimple configurations. The paper discusses various surface geometric parameters, arrangement patterns, and orientations, along with their influence on thermal performance and pressure drop characteristics. The numerical and experimental investigation reveal that combining ribs with dimples or protrusions can increase the Nusselt number by approximately 20% to 90% as compared to smooth surfaces through depending on geometry and flow conditions. Mostly the teardrop-shaped dimples and arc-shaped ribs have superior heat transfer augmentation with enhancements often exceeding 50% while maintaining manageable pressure drops (friction factor increase typically between 10% to 40%). Further, the Curved or angled rib geometries boost turbulence intensity and gives an additional 10-15% heat transfer improvement. Furthermore, the review highlights hybrid techniques combining ribs and dimples. They offer high heat transfer efficiency with reduced pressure drop, making them viable for practical applications. The objective is to identify effective design strategies and outline future directions for research and practical implementation in the present scenario.
Keywords: Dimple, Friction Factor, Heat Transfer Enhancement, Nusselt Number, Rib.