Study of heat and fluid characteristics of Al2O3 nanofluid in a concentric tube heat exchanger fitted with a peripherally cut spiral tape of different geometrical shapes

Abstract

This paper presents a comprehensive numerical investigation into the heat transfer characteristics of a concentrictube heat exchanger fitted with simple and modified spiral tape inserts. The study employs Al2O3 nanofluid with different concentration rates.The simulations are carried out using ANSYS Fluent software. The research begins with the validation of simulations using twisted tape inserts, aligning the results with an experimental benchmark. Subsequently, grid independence analyses are performed for the simple spiral tape and four other variations of modified spiral tape inserts.
The study then delves into the impact of various parameters on heat transfer enhancement enabled by the spiral tape inserts. Through the utilization of the Design of Experiments (DOE) methodology, three key parameters—namely, cut dimension, gap between the tube and the spiral surface, and inlet velocity—are systematically varied to identify their optimal values. With these optimized parameters established, investigations encompass three different pitch values for the tape inserts, followed by an exploration of three distinct nanofluid concentrations to identify the most effective concentration.