Yang Li, Baghaei Shaghayegh, Suksatan Wanich, Barnoon Pouya, Sharma Sandhir, Davidyants Alla, El-Shafay A S
School of Equipment Engineering, Shenyang Ligong University, Shenyang, 110159, Liao Ning, China.
Department of Mechanical Engineering, Khomeinishahr Branch, Islamic Azad University, Isfahan, Iran.
Sci Rep. 2022 Feb 10;12(1):2245. doi: 10.1038/s41598-022-06049-2.
This study is devoted to the numerical assessment of the influence of helical baffle on the hydrothermal aspects and irreversibility behavior of the turbulent forced convection flow of water-CuO nanofluid (NF) inside a hairpin heat exchanger with 100 mm length, 10 mm inner tube internal diameter, and 15 mm outer diameter internal diameter. The variations of the first-law and second-law performance metrics are investigated in terms of Reynolds number (Re = 5000-10,000), volume concentration of NF ([Formula: see text]) and baffle pitch (B = 25-100 mm). The results show that the NF Nusselt number grows with the rise of both the Re and [Formula: see text] whereas it declines with the rise of B. In addition, the outcomes depicted that the rise of both Re and [Formula: see text] results in the rise of pressure drop, while it declines with the increase of B. Moreover, it was found that the best thermal performance of NF is equal to 1.067, which belongs to the case B = 33.3 mm, [Formula: see text]=2%, and Re = 10,000. Furthermore, it was shown that irreversibilities due to fluid friction and heat transfer augment with the rise of Re while the rise of B results in the decrease of frictional irreversibilities. Finally, the outcomes revealed that with the rise of B, the heat transfer irreversibilities first intensify and then diminish.
本研究致力于数值评估螺旋折流板对水 - 氧化铜纳米流体（NF）在长度为100毫米、内管内径为10毫米、外径为15毫米的U形管换热器内湍流强制对流流动的热质传递方面及不可逆性的影响。根据雷诺数（Re = 5000 - 10000）、纳米流体的体积浓度（[公式：见原文]）和折流板间距（B = 25 - 100毫米），研究了第一定律和第二定律性能指标的变化。结果表明，纳米流体的努塞尔数随雷诺数和[公式：见原文]的增加而增大，随折流板间距的增大而减小。此外，结果表明，雷诺数和[公式：见原文]的增加都会导致压降增大，而随折流板间距的增加而减小。而且，发现纳米流体的最佳热性能等于1.067，属于折流板间距B = 33.3毫米、[公式：见原文]=2%、雷诺数Re = 10000的情况。此外，研究表明，由于流体摩擦和传热引起的不可逆性随雷诺数的增加而增大，而折流板间距的增加会导致摩擦不可逆性的减小。最后，结果表明，随着折流板间距的增加，传热不可逆性先增强后减弱。
