Abstract This paper investigates the irreversibilities caused by fluid flowing under the effect of isothermal walls of fin-tube heat exchanger in the presence of longitudinal vortex generators. Inline arrangement of circular tubes with fin-surface mounted rectangular winglet pairs (RWPs) arranged in common flow down configuration are selected for the present three-dimensional numerical study. Initially, thermodynamic performance analysis of different possible RWP locations corresponding to tubes has been examined for a fixed angle of attack. Further, the study is expanded for some specific locations by varying angle of attack ranging from 15° to 60° and flow Reynolds number ranging from 2000 to 4000. Thermodynamic performance of the present system has been evaluated by analyzing the irreversibilities caused due to RWPs and compared with the thermo-hydraulic performance. Thermodynamic analysis is categorized into two parts: the first ‘entropy generation analysis’ and the second ‘exergy analysis’. For entropy generation analysis entropy generation rate, irreversibility distribution ratio and Bejan number are examined. The obtained results indicate that the irreversibility caused by entropy generation in the present system is majorly dominated by the entropy generation rate due to thermal effect. Exergy analysis is studied by calculating the irreversibility rate, exergy destruction number, heat transfer improvement number and exergetic efficiency. The observation of exergetic efficiency variation for different RWP locations demonstrates that the present system with upstream RWP locations delivers higher performance.

中文翻译：

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存在矩形小翼对的直列翅片管换热器的热力学性能分析

摘要 本文研究了在纵向涡流发生器存在的情况下，在翅片管换热器等温壁的作用下，流体流动引起的不可逆性。目前的三维数值研究选择了具有翅片表面安装的矩形小翼对 (RWP) 的圆形管的内嵌排列，这些小翼对 (RWP) 以常见的向下流动配置排列。最初，已针对固定攻角检查了与管对应的不同可能 RWP 位置的热力学性能分析。此外，通过从 15° 到 60° 的不同攻角和从 2000 到 4000 的流动雷诺数，该研究针对某些特定位置进行了扩展。本系统的热力学性能已通过分析由 RWP 引起的不可逆性并与热工水力性能进行比较来评估。热力学分析分为两部分：第一个“熵生成分析”和第二个“火用分析”。对于熵生成分析熵生成率、不可逆分布比和贝扬数进行了检查。所得结果表明，本系统中熵产生引起的不可逆性主要由热效应引起的熵产生率决定。通过计算不可逆率、火用破坏数、传热改进数和火用效率来研究火用分析。