Numerical thermal augmentation of ternary nanofluid in a tube with stent, torus-ring and surface-grooved twisted tapes under non-uniform wall temperature

Abstract

This paper presents a numerical analysis of flow and thermal characteristics in a plain tube with various inserts, including a stent, torus ring, and surface-grooved twisted tape, using a ternary nanofluid consisting of SiO2, ZnO, and CaO nanoparticles as the working fluid. Computational fluid dynamics simulations were conducted using ANSYS Fluent commercial codes, focusing on laminar Reynolds numbers ranging from 500 to 2000 and a non-uniform wall temperature profile. The objective is to investigate the Nusselt number, pressure drop, thermal performance, and pumping power of the ternary nanofluid with nanoparticle concentrations ranging from 0.01 to 0.05%, considering various geometrical parameters of the grooved twisted tape insert, such as thickness ratio (0.019–0.033), width ratio (0.38–0.68), and pitch ratio (1.77–5.77). The results show that flow and thermal indicators such as Nusselt number, thermal performance factor, pressure drop and pumping power increased with thickness and width ratios. Conversely, an increase in pitch ratio results in lower flow and thermal indicators. For instance, in a plane tube without inserts, no noticeable difference in pressure drop is observed and the thermal performance factor is about 1.87-1.25 times that of pure water when nanoparticle concentration is increased from 0.01 to 0.05%. The width ratio 0.68, thickness ratio 0.033 and pitch ratio 1.77 yielded a maximum thermal performance factor of about 1.4, 1.7 and 2.3 more than smooth tube, respectively, and a maximum pumping power 0.000654 W, 0.000223 W and 0.00020 W, respectively. The findings emphasize significant improvements in heat transfer and flow properties, shedding light on the innovative configuration's potential application as an improved heat exchanger. This research advances understanding of ternary nanofluid behavior and provides useful information for enhancing heat transfer in a variety of engineering applications.