Experimental analysis to estimate thermal performance of double pipe heat exchanger using Circular cut longitudinal strip

Heat exchangers are critical thermal devices used across industries for energy transfer.The double pipe heat exchanger (DPHE) is one of the simplest designs but has inherent limitations in heat transfer performance.This study presents an experimental and numerical investigation of heat transfer enhancement in DPHEs using plane tape inserts with holes, a relatively underexplored passive enhancement technique.An experimental setup was fabricated as per ASHRAE standards and tested with holed tapes of varying diameters one 1 plane and (2, 4, and 6 mm) and diameter-to-depth (D/H) ratios (1.5, 3, and 6).Thermal parameters including Nusselt number (Nu), friction factor (f), and performance evaluation criterion (PEC) were measured across a range of Reynolds numbers.CFD validation was also conducted using ANSYS Fluent for selected configurations.Results showed that holed plane tapes significantly enhanced heat transfer compared to plain tubes and plain tapes, with the best configuration achieved at 6 mm hole diameter and D/H ratio of 3.This design provided a maximum Nu of 113.68 at Re = 14000, while maintaining moderate pressure losses.Overall, holed plane tapes represent a cost-effective, energy-efficient passive technique for compact heat exchangers used in food, oil, and chemical industries.