Thermo-hydraulic performance optimization of different louvered strip inserts inside a heated tube employing Al<sub>2</sub>O<sub>3</sub> and CuO water-based nanofluids.

Abstract

Louvered strip insert (LSI) within heat exchangers is a widely used method for enhancing performance. However, optimization analysis on such inserts with many design parameters is limited in the literature. In accordance, the present study aims to conduct a thermo-hydraulic performance optimization. Using a surrogate-based optimization approach accompanied by 3D full numerical simulations. Four parameters are varied simultaneously namely: the slant angle (θ) between 5° and 39°, the pitch (P) between 85 mm and 106 mm, the Reynolds number (Re) range of 500 - 13,000, and the nanofluid concentrations (ϕ) between 0% and 2%. Two nanofluids are tested: Al₂O₃, and CuO using water as the base fluid. The LSI is installed in the forward direction to the fluid inlet inside a tube with a diameter (D) of 14.3 mm and a length (L) of 2219 mm.The optimization analysis is based on both boosting the heat transfer amount and the degradation of the friction factor through five performance indices. The results revealed that CuO nanofluid performs better than other tested fluids. A maximum overall performance factor of 2.61 is reached at optimum values of the design parameters Re, ϕ, θ, and P as: 500, 0.82%, 35°, and 105.37 mm, respectively. This work is useful for the optimum design of heat exchanger devices.