Thermal-frictional behavior of new special shape twisted tape and helical coiled wire turbulators in engine heat exchangers system

Abstract

This study proposes a novel twisted tape turbulator with a unique DNA-like shape, referred to as the special shape twisted tape turbulator (SSTT), to augment the heat transfer efficiency within heat exchanger conduits. This turbulator is composed of segmented components and facilitates the passage of fluid flow through the gaps while inducing swirling motion along the conduit. The pitch ratio of the segments has been examined within the range of 1–4 mm to evaluate its impact on the heat transfer properties. The findings indicate that the novel geometry offers notable benefits compared to a basic twisted tape design. Optimal heat transfer occurs at a pitch ratio of 2 mm, resulting in a 125% improvement over a plain tube. To further improve thermal efficiency, a helical coiled wire turbulator is incorporated alongside the tube, in combination with the chosen SSTT. The findings indicated a 142% rise in the heat transfer coefficient, accompanied by a 960% increase in pressure drop in the presence of these turbulators. Consequently, the thermal performance reached 1.31, representing a 20% improvement compared to a basic twisted tape turbulator.