Investigate the Impact of Dimple Size and Distribution on the Hydrothermal Performance of Dimpled Heat Exchanger Tubes

In this study, the primary objective was to enhance the hydrothermal performance of a dimpled tube by addressing areas with low heat transfer compared to other regions. To accomplish this, a comprehensive numerical investigation was conducted using ANSYS Fluent 2022 R1 software, focusing on different diameters of dimples along the pipe’s length and the distribution of dimples in both in-line and staggered arrangements. The simulations utilized the finite element method to address turbulent flow within the tube by solving partial differential equations, encompassing Re numbers spanning from 3000 to 8000. The study specifically examined single-phase flow conditions, with water utilized as the cooling fluid. The results of the investigation indicated that increasing the Reynolds number resulted in higher average Nusselt numbers, pressure drops, the overall performance criterion, and a reduction in average thermal resistance across all models analyzed. Notably, both proposed models demonstrated improved heat transfer when compared to the conventional model. Out of all the models evaluated, the tube featuring staggered dimples (Model B) demonstrated the most notable improvement in the Nu number. It exhibited an enhancement of approximately twice the value compared to the conventional model. The mean thermal resistance for the tube with dimples in the staggered arrangement (Model B) is 0.0057 k/W, compared to 0.0118 k/W for the traditional model. The maximum overall performance criterion for Model -A- and Model -B- is 1.22 and 1.33, respectively.