An experiment was conducted to investigate the heat transfer characteristics and friction factor characteristics of a concentric tube fitted with triangular-cut twisted tape (TCTT) insert with a twist ratio Y of 5.4 and depth of triangular cut of 1.2 cm, which were studied for laminar flow. This investigation also is used to find the heat transfer coefficient, Nusselt number and Reynolds number. The heat transfer enhancement was caused with the flow of fluid between the plain twisted tapes and TCTT. The experimental value of plain tube and triangular-cut twisted tube obtained from the experimental work and these two statistical data were compared with the results. The results show that the enhancement of heat transfer rate induced with plain and TCTT inserts increases with the increase in Reynolds number. The Reynolds numbers were varied in the range of 5710–18,366. The Reynolds number in the tube with triangular- cut twisted tape insert were enhanced by 1.1–1.3 times compared with smooth twisted tape inserts. The configuration of TCTT insert offered higher heat transfer rate and friction factor than that of the plain twisted inserts.

中文翻译：

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三角形切扭带（TCTT）插入件的传热和摩擦系数特性的实验研究

进行了一项实验，研究装有扭曲比为Y的三角切扭带（TCTT）的同心管的传热特性和摩擦系数特性研究了层流的5.4和三角形切口的深度1.2厘米。该研究还用于找到传热系数，努塞尔数和雷诺数。传热的增强是由于平捻带和TCTT之间的流体流动引起的。将实验工作中获得的平管和三角切扭管的实验值以及这两个统计数据与结果进行比较。结果表明，随着雷诺数的增加，由普通和TCTT刀片诱导的传热速率增强。雷诺数在5710-18366之间变化。与光滑的扭曲带状插入物相比，三角形切割的扭曲带状插入物在管中的雷诺数增加了1.1-1.3倍。