Experimental investigation on spatial phase distributions for various flow patterns and frictional pressure drop characteristics of gas liquid two-phase flow in a horizontal helically coiled rectangular tube

Spatial phase distributions for various flow patterns and two phase flow frictional pressure drops of air–water flow in a horizontal helically coiled rectangular tube were experimentally investigated at the liquid and gas superficial velocities of 0.11–2 m/s and 0.13–16 m/s. Local void factions in the helically coiled tube were measured with electric conductivity probes and the corresponding flow regimes were recorded with a high-speed video camera simultaneously. The local void fractions and spatial phase distributions for various flow regimes were analyzed according to the physical mechanisms. The spatial phase distributions of gas liquid two-phase flow in the helically coiled tube are mainly affected by the gravitational and centrifugal forces. The measured single-phase flow and two-phase flow pressure drops have been analyzed for various flow regimes. A correlation was proposed to predict the friction pressure drop of single-phase flow in the helically coiled tube. The existing gas–liquid two- phase pressure drop frictional correlations were compared to the experimental frictional pressure drop data. The Awwad et al. correlation [Int. J. Multiphase Flow, 21 (1995), 607–619] predicts 91 % of the experimental data within ± 30 %.