Numerical Analysis of Heat Transfer in the Carbon Nanotube-Water Based Nanofluid Flowing Around a Square Cylinder Inside the Channel

Abstract

The nanofluid with exceptional thermo-physical properties exhibits its significance effect over the convectional fluids for improved heat transfer characteristics. The numerical analysis of heat transfer rate is crucial in many designing and optimizing thermal systems including, heat exchangers, power plants and engines. In this work, numerical investigations carried out for forced convection heat transfer of CNT-water nanofluid over a 45.- inclined square cylinder. The aim of the study to determine the optimum conditions for maximum heat transfer. The value of Reynolds number, CNTs nanoparticles volume fraction, and confinement ratio are consider as input variables, Response Surface Methodology (RSM) is used for optimization to identify the optimal values of the input variables that will result in the best response of heat transfer. The response surface equation is evaluated using the design of the experiments, model fitting, and model optimization. The numerical simulation is performed for different Reynolds numbers (1 ≤ Re ≤ 40), the volume fraction of CNTs (0 ≤ Φ ≤ 0.05), and the confinement ratio (0.1 ≤ λ ≤ 0.5). It was found that the heat transfer enchancement is observed by increasing the Reynolds number, volume fraction and confinement ratio, consequently the temperature gradient increases near the square cylinder. It is also found that the maximum Nusselt number is found at Re = 40, Φ = 0.05 and λ = 0.5. A comparison is also made between the numerical results obtained from the CFD analysis and RSM. Overall, the finding highlighted optimum value of Re, Φ and λ makes the CNTs nanofluid suitable for effective heat transfer applications, aiding in design and thermal system optimization.