Summary:
This paper presents an optimizaton study on a heat exchanger tube inserted with circular rings by using numerical analysis results. Pitch length (P), inner diameter (d) and thickness (t) of the rings are considered as factors to be optimized. Water is selected as working fluid and the tube is considered under constant heat flux and turbulent flow condition. k-ε RNG turbulent model is used to simulate the turbulent flow thorugh the tube. L9 design of experiment model is used to reduce the number of numerical runs which is proposed by Taguchi method. The optimization study is conducted as single and multi objective optimization by using Taguchi method and Grey relation analysis. Furthermore, the contribution effects of the considered parameters on the Nu and the f result are revealed by ANOVA. Numerical resutls showed that the Nu and the f increases as the P, the d and the t decreases. It is found that the most effective parameters on both the Nu and the f is inner diameter of the rings. For the single-objective optimization, the highest Nu and the lowest f is obtained with the tube configuration that are found as the P of 50 mm, the d of 10 mm and the t of 5 mm and the P of 200 mm, the d of 15 mm and the t of 3.0 mm, respectively. The P of 50 mm, the d of 15.0 mm and the t of 5.0 mm presents the best thermal and hydraulic performance according to the multi-objective optimization study.