Heat transfer enhancement and performance of compact heat exchangers have been extensively studied in the past century for the purpose of promoting energy efficiency. Microfin tubes in single/two/multiple-phase flow heat exchangers into which twisted tape swirl generators are installed can promote heat transfer with a moderate pressure loss penalty. This article reports on the enhanced heat transfer of silver–water nanofluids in a microfin tube into which loose-fit twisted tapes are installed in a counter-flow arrangement. The experiments were carried out using nanofluids with various silver concentrations (0.007–0.03 vol%), loose-fit twisted tapes with clearance ratios (c/D) of 0.0 (tight-fit), 0.05, 0.075 and 0.1, for a twist ratio, y/W, of 2.0. The results indicate that the heat transfer rate (Nu) and pressure drop (f) increase with a decrease in clearance ratio (c/D) and increase in silver (Ag) nanoparticle concentration. Additionally, the thermal performance factor tends to increase with the decrease in Reynolds numbers.

中文翻译：

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银水纳米流体流动和对流传热，该微翅片管配有松配合的扭曲带

在过去的世纪中，以提高能量效率为目的，已经对紧凑型热交换器的传热增强和性能进行了广泛的研究。单/二/多相流换热器中的微型翅片管（安装了扭曲的带状涡流发生器）可以促进热传递，并具有适度的压力损失损失。本文报道了微翅片管中银-水纳米流体传热的增强，在微翅片管中以逆流方式安装了松散扭曲的带子。实验是使用具有各种银浓度（0.007–0.03体积％）的纳米流体，间隙比（c / D）为0.0（紧密配合），0.05、0.075和0.1的松配合扭曲带进行的， ，y / W，共2.0。结果表明，传热速率（Nu）和压降（f）随着清除率（c / D）的降低和银（Ag）纳米颗粒浓度的增加而增加。另外，热性能因数倾向于随着雷诺数的减少而增加。