Abed Nabeel, Afgan Imran, Iacovides Hector, Cioncolini Andrea, Khurshid Ilyas, Nasser Adel
Department of Mechanical, Aerospace and Civil Engineering, School of Engineering, University of Manchester, Manchester M13 9PL, UK.
Mechanical Technical Department, Technical Institute of Anbar, Middle Technical University, Baghdad 10066, Iraq.
Nanomaterials (Basel). 2021 Mar 26;11(4):853. doi: 10.3390/nano11040853.
In this study, we numerically investigated the effect of swirl inserts with and without nanofluids over a range of Reynolds numbers for parabolic trough collectors with non-uniform heating. Three approaches were utilized to enhance the thermal-hydraulic performance-the variation of geometrical properties of a single canonical insert to find the optimized shape; the use of nanofluids and analysis of the effect of both the aforementioned approaches; the use of swirl generators and nanofluids together. Results revealed that using the straight conical strips alone enhanced the Nusselt number by 47.13%. However, the use of nanofluids along with the swirl generators increased the Nusselt number by 57.48%. These improvements reduced the thermal losses by 22.3% for swirl generators with nanofluids, as opposed to a reduction of only 15.7% with nanofluids alone. The investigation of different swirl generator designs showed various levels of improvements in terms of the overall thermal efficiency and thermal exergy efficiency. The larger swirl generator (H30mm-θ30°-N4) with 6% SiO nanofluids was found to be the optimum configuration, which improved the overall collector efficiency and thermal exergy by 14.62% and 14.47%, respectively.
在本研究中，我们对带有和不带有纳米流体的旋流插入件在一系列雷诺数下对非均匀加热抛物槽式集热器的影响进行了数值研究。采用了三种方法来提高热工水力性能——改变单个标准插入件的几何特性以找到优化形状；使用纳米流体并分析上述两种方法的效果；同时使用旋流发生器和纳米流体。结果表明，单独使用直锥形条可使努塞尔数提高47.13%。然而，将纳米流体与旋流发生器一起使用可使努塞尔数提高57.48%。这些改进使带有纳米流体的旋流发生器的热损失降低了22.3%，而仅使用纳米流体时热损失仅降低了15.7%。对不同旋流发生器设计的研究表明，在整体热效率和热（火用）效率方面有不同程度的提高。发现带有6% SiO纳米流体的较大旋流发生器（H30mm-θ30°-N4）是最佳配置，它分别将集热器的整体效率和热（火用）提高了14.62%和14.47%。
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