Minimizing the entropy generation rate is one of the key performance indicators for enhancing the thermal design of heat exchangers. This paper introduces a comprehensive numerical entropy generation analysis of turbulent water flow inside—newly proposed—conical tubes with dimples subjected to a constant heat flux. The effect of different tube diameter ratios (DR = 1, 1.5, 2, 3, and 5) and flow modes (convergent and divergent tube configurations) on the thermal, viscous, and total entropy generation rates is investigated within Reynolds number (Re) range of 3 × 10³–40 × 10³ using ANSYS-Fluent package. Realizable k-ε (RKE) turbulence model is adopted in this study. A well-validated 3D model was adopted to estimate the dimensionless indices: Bejan number (Be), enhanced entropy generation ratio (N_s,en), and the irreversibility distribution ratio (\({\phi }_{\mathrm{s}}\)) to characterize the entropy generation performance and to compare conical dimpled tubes to smooth ones. The results showed that total entropy production rate values for dimpled tube geometries are lower than those for the corresponding smooth ones, especially for convergent dimpled tubes. Convergent dimpled tubes with DR in the range of 1.5–3 achieved the lowest total entropy production values over the whole Re range, with an average value of 0.20 W K⁻¹, as compared to an average value of 0.34 W K⁻¹ for the smooth configurations. The average N_s,en values for dimpled convergent tubes with DR = 1.5–3 are 0.46 and 0.80 at Re = 3000 and 40,000, with reductions of 50.54% and 3.61% at both Re values, respectively. The study also showed that the entropy generation analysis could provide an effective tool to highlight the optimal design of tube heat exchangers based on the minimum entropy generation and the enhanced entropy generation ratio.

最小化熵产生率是加强换热器热设计的关键性能指标之一。本文介绍了新提出的带有凹坑的锥形管内的湍流水流的综合数值熵生成分析，该管受到恒定热通量的影响。在雷诺数 (Re) 内研究了不同管径比（DR = 1、1.5、2、3 和 5）和流动模式（会聚和发散管配置）对热、粘性和总熵产生率的影响范围为 3 × 10 ³ –40 × 10 ³使用 ANSYS-Fluent 包。可实现的k - ε(RKE)湍流模型在本研究中被采用。采用经过充分验证的 3D 模型来估计无量纲指标：Bejan 数 (Be)、增强熵生成率 ( N _s,en ) 和不可逆性分布率 ( \({\phi }_{\mathrm{s} }\) ) 来表征熵产生性能，并将圆锥形凹坑管与光滑管进行比较。结果表明，波纹管几何形状的总熵产生率值低于相应的光滑管，尤其是会聚波纹管。DR 在 1.5–3 范围内的会聚波纹管在整个 Re 范围内实现了最低的总熵产值，平均值为 0.20 WK ^-1，与平滑配置的平均值 0.34 WK ^-1相比。在 Re = 3000 和 40,000 时，DR = 1.5–3 的凹陷会聚管的平均N _{s,en值为 0.46 和 0.80，两个 Re 值分别减少 50.54% 和 3.61%。}该研究还表明，熵生成分析可以提供一种有效的工具，以突出基于最小熵生成和增强熵生成比的管式换热器的优化设计。