Enhancing the heat transfer efficiency of an engine heat exchanger through the utilization of an innovative conical braided wire turbulator

Abstract

This study introduces innovative turbulators with unique geometries, namely the Conical Simple Wire Turbulator (CSWT) and Conical Braided Wire Turbulator (CBWT), designed to enhance heat transfer in a constant temperature tube. These turbulators resemble a conical shape in appearance but are constructed by interconnecting multiple wires, enabling fluid flow to pass through. The distinct geometry of these turbulators not only disrupts the thermal boundary layer for improved heat transfer and Thermal Enhancement Factor (TEF), and results in a favorable pressure drop. The study explored various geometrical parameters of the turbulator, including wire diameters (a) ranging from 0.5 to 1.5 mm and turbulator gaps (TG) ranging from −10 to 30 mm. Using the RNG k–ε model, the finite-volume scheme is utilized to discretize the turbulence flow equations. A numerical investigation was conducted across Reynolds numbers ranging from 5500 to 12375. The results show that increasing the wire diameter and reducing the turbulator gaps simultaneously enhanced heat transfer, pressure drop, and TEF. The highest heat transfer and TEF were achieved with the CBWT featuring a 1.5 mm wire diameter and a −10 mm TG. In this configuration, Nusselt was 2.84 times greater than a plain tube, with a maximum TEF recorded at 1.4.