Effect of wired nails circular–rod inserts on tube side performance of shell and tube heat exchanger: Experimental study

In this paper, the thermal, hydraulic, and thermodynamic performances in a shell and tube heat exchanger fitted with wired-nails circular–cut rod inserts on tube side are investigated experimentally. Thermal performance is expressed in terms of overall heat transfer coefficient (U), effectiveness (ε), and number of transfer unit (NTU), while hydraulic and thermodynamic performances are expressed in tube-side pressure drop and exergy efficiency, respectively. The tube side flow rate of hot water varies from (13–18) LPM while a constant flow rate of cold water on the shell side (i.e. 18 LPM) is considered. The experiments are performed for two configurations of wired-nails circular–cut rod inserts with different numbers of nails, varied space between them, and five different configurations of insert distribution in tubes. Also pressure drop is measured and exergy analysis is performed. All data obtained is compared with the conventional plain tube heat exchanger. The experimental results reveal that the proposed inserts configurations have a significant improvement on heat exchanger thermal and thermodynamic performances and a drawback in hydraulic performance. Percentages augmentation in U, NTU, ε, and exergy efficiency are (210–280%), (132–149%), (185–224%), and (130–210%), respectively over the conventional design.