Experimental Heat Transfer ( IF 3.5 ) Pub Date : 2020-09-10 , DOI: 10.1080/08916152.2020.1817177 S.M. Hassani 1 , M. Khoshvaght-Aliabadi 2 , A. Feizabadi 3 , S. Rehman 4 , A. Alimoradi 5, 6
ABSTRACT
Turbulators have been developed as a capable passive technique for enhancing heat transfer through channels. The shape and arrangement of these geometries are the main factors in their performance. In the current analysis, three curved turbulators, i.e. circular (C), rectangular (R), and diamond (D), with four various arrangements, i.e. forward-vertical (FV), forward-horizontal (FH), backward-vertical (BV), and backward-horizontal (BH), inside a rectangular channel at the constant heat flux are examined. The thermal and aerodynamic characteristics are analyzed using the dimensional parameters of h and ∆p as well as the dimensionless parameters of Nuenh/Nusmo vs. fenh/fsmo. Based on experimental data and their corresponding numerical results, the effects of both shape and arrangement on streamlines and contours of airflow are discussed. Also, a performance index (η) is applied to apprise overall thermal-aerodynamic performance at inlet velocities of 1, 2, and 3 m/s. The results show that the value of η has a deceasing trend with the inlet velocity, indicating a better performance is found at lower velocity for these turbulators. The best performance could be achieved by the C turbulators at the FV arrangement (CFV model with η between 1.36 and 1.52), followed the DFH model with η between 1.35 and 1.49.
中文翻译:
通过矩形通道的不同布置的弯曲湍流器的实验和数值分析
摘要
湍流器已被开发为一种有效的被动技术,用于增强通过通道的热传递。这些几何形状的形状和排列是其性能的主要因素。在当前的分析中,三个弯曲的湍流器,即圆形(C)、矩形(R)和菱形(D),有四种不同的排列方式,即前向垂直(FV)、前向水平(FH)、后向垂直( BV)和后向水平(BH),在恒定热通量的矩形通道内进行检查。使用h和Δp的量纲参数以及Nu enh / Nu smo vs. f enh /的无量纲参数分析热和空气动力学特性˚F SMO。基于实验数据及其相应的数值结果,讨论了形状和排列对气流流线和轮廓的影响。此外,性能指数 ( η ) 用于评估在 1、2 和 3 m/s 入口速度下的整体热空气动力学性能。结果表明,η值随入口速度呈下降趋势,表明这些湍流器在较低速度下具有更好的性能。最佳性能可以通过 FV 布置的 C 湍流器(CFV 模型,η介于 1.36 和 1.52 之间),其次是 DFH 模型,η介于 1.35 和 1.49 之间。