The thermo-hydraulic properties of circular tubes with a twisted tape inside (used accordingly to induce turbulence and enhance heat transfer through the tube wall) are described for Reynolds Numbers ranging from 830 to 1990. Tapes twisted with the three distinct twist ratios are considered, namely, 6, 4.4 and 3. Air is used as the working fluid in several tests. For the sake of comparison, the standard tube with no insert is also examined. It is shown that in the presence of the twisted tape, the 'frictional factor' , 'Nusselt Number' and the 'thermal performance factor' are much higher than those obtained for the plain tube. Moreover, the tapes having the lowest twist ratio, i.e., 3, are more effective than the others in terms of heat transfer augmentation. The 'thermal performance factor' is greater than one for all the twisted tapes used in the experiments, which confirms the enhanced performances of the heat exchanger and the related savings in terms of total energy.

This research intends to look into the transformation of heat, factors affecting the friction, and characteristics of the efficacy ratio for the ratio of twist as 3.0, 4.4, and 6.0, independently of a concentric pipe heat exchanger with and without trapezoidal section twisted tape insert. For different Reynold’s Number (Re) ranges of 200-2000, 800-2000, and 2000-12000, experimentation was accomplished to find the transformation of heat energy and aspect of factors of the friction of coaxial tubes. The investigated data from the tube without an insert were compared to the conventional correspondence to assure that the investigation output was valid. The findings of the trapezoidal section twisted tape tube has been in contrast to the simple tube’s results. The consequences reveal that the trapezoidal section twisted tape appreciably improves heat transmission along with friction coefficient. The Trapezoidal section twisted tape enhancement transmission of heat was once additionally judged to be practical because the realized output ratio is maximum than unity. The twisted tape has a greater Nusselt Number (Nu), frictional influence, and overall efficacy attainment than a plain tube, by the research. According to the tapes that have been tested, the tapes with the lowest twist ratio 3.0 are greater fine than the tapes with the other ratio of twist, as a consequence of the fact that the tape with the lowest ratio of twist is the most environmentally friendly at supplying heat augmentation.

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The thermal behavior of pipes with a twisted tape inside (used to enhance heat transfer through the tube wall) is studied in the laminar flow regime. Oil is used as the work fluid with the corresponding Reynolds Number spanning the interval 200-2000. It is found that in such conditions the 'Nusselt Number' (Nu) gradually increases with reducing the tape twist ratio, whereas the friction factor is detrimentally affected by the presence of the tape (as witnessed by the comparison with the companion case where a plain tube is considered). In particular, it is shown that the heat transfer efficiency can be improved by nearly 69% if tape inserts with a relatively low twist ratio are used. On the basis of these findings, it is concluded that loose fit tape inserts are superior to tight fit tapes in terms of heat transfer and ease of replacement.