Additively Manufactured Butterfly-Shaped Inserts for Enhanced Heat Transfer in Tubular Heat Exchangers: Experimental Insights

Abstract. The use of insert flow devices is an interesting passive heat transfer enhancement technique that promotes boundary layers’ disruption and fluid mixing. Different inserts have been proposed for tubular heat exchangers over the past decades, including twisted tapes, wired coils, conical rings and butterflyshaped geometries. This work aims to experimentally evaluate three additively manufactured geometries derived from a butterfly-shaped base design previously studied in literature. The influence of butterfly-shaped inserts on overall thermofluid dynamics was experimentally analysed by adopting the infrared thermographic technique. In the present study, the focus shifts to investigating the local thermal performance of these additively manufactured geometries. The collected data highlight that more efficient wall cooling, from the thermofluidic standpoint, can be achieved by means of drilled configurations, which effectively mitigate fluid stagnation through lower fluid flow perturbation. The results are particularly valuable for designing heat exchangers in applications that demand precise temperature control, such as those in the pharmaceutical and food industries.