Flow of Viscoelastic Fluid through a Helical Coil

A. Sobti, R. Sehgal and R. K. Wanchoo

Abstract
The study aims at quantifying the effect of fluid elasticity on frictional pressure drop for the flow of viscoelastic fluid through a helical coil. Aqueous solutions of polyacrylamide (PAA) in the concentration range 0.25 %–0.5 % (wt/vol.) were used as test fluids. The fluids were characterized using dynamic rheometer under rotational and oscillatory modes. The rheological study depicts that the fluids exhibit elasticity and shear thinning behavior. Experimental data on pressure drop for the flow of non-Newtonian viscoelastic fluid through a helical coil have been generated. Drag enhancement was observed for the fluids with significant elastic character. An existing correlation applicable over a wide range of Germano number (NGn) for the flow of Newtonian fluids through helical coils (11.7≤Dc/dt≤105.48, 8.3≤p/Dt≤66.7), proposed by Gupta et al.22, has been extended to non-Newtonian viscoelastic fluids by incorporating the effect of fluid elasticity in terms of Weissenberg number (We). The proposed model’s uncertainty has been reported for 95 % confidence to assess the significance of newly reported results. The observed data were compared with the available models in the literature statistically using mean relative quadratic error (MRQE) and arithmetic relative error (%ARE). Lower values of MRQE and %ARE depict the acceptability of the proposed model. (This work is licensed under a Creative Commons Attribution 4.0 International License.)

This work is licensed under a Creative Commons Attribution 4.0 International License

Keywords
pressure drop, viscoelastic fluid, helical coil, fluid elasticity, Germano number, Weissenberg number