In this paper the effects of curvature ratio and torsion on friction factor (f) and Nusselt number (Nu) from coiled tubes were investigated. Hot water was passed through coiled tubes placed in a cold bath. At various Reynolds numbers, Nu, f and thermal–hydraulic performance were obtained. Empirical correlations were proposed to estimate Nu and f using the genetic algorithm. The genetic algorithm-based multi-objective optimization was used for the optimization.
