Comparative numerical study on pressure drop in helically coiled and longitudinally C-shaped pipes

Abstract

In the present work, the shear stress transport (SST) $$k - \omega$$ model is used to simulate internal turbulent flows in curved tubular heat exchangers and the resulting friction factors $$C_{f}$$ are calculated. A helically coiled configuration was used in the validation process of the model that showed a good agreement between numerical results of the friction factors $$C_{f}$$ and the standard experimental correlations of the literature, with a maximum relative error of 4.24%. A comparative study was performed to investigate the possibility of applying friction factor correlations, established mainly for helical coils, to longitudinally C-shaped pipes. Preliminary results confirm the inability of coil-specific correlations to predict the friction factor $$C_{f}$$ inside C-shaped pipes. It was also noted that, unlike helical coils, the C-shaped pipe friction factor appears to be affected by ratios other than the curvature ratio as highlighted in this study by introducing the effect of the amplitude ratio $$\beta$$ defined as the ratio of the amplitude to the curvature radius.