Countercurrent gas-pseudoplastic liquid two-phase flow

Countercurrent flow limitation (flooding), two-phase flow patterns, and voi d fraction in countercurrent flow of gas-pseudoplastic liquids in a vertica l and an inclined channel (with a 68 degrees inclination angle with respect to the horizontal plane) were experimentally studied. The test section was a transparent tube, 2.36 m long with a 1.9 cm inner diameter. Aqueous 500 and 1000 ppm solutions of PERCOL 727 (a copolymer of sodium acrylate and ac rylamide) with flow behavior indices of 0.58 and 0.35, respectively, were u sed as the liquid phase, and air constituted the gas phase. The gas and liq uid superficial velocity ranges in the experiments were 0.5-198 and 0.8-34 cm/s, respectively. The flooding curves of both polymer solutions were simi lar for both angles of inclination and were similar to the flooding curves of low-viscosity Newtonian liquids. They thus indicate little effect of pse udoplasticity on flooding. The visually observed two-phase flow regimes wer e bubbly/slug, slug, slug/churn, and churn. Annular flow occurred only at n ear-flooding conditions. The flow regime transition lines showed significan t differences with data representing a Newtonian liquid with a viscosity of the same order of magnitude as the polymer solution apparent viscosities. The slug flow pattern, characterized by Taylor bubbles, was the most domina nt flow pattern. The measured void fractions were correlated based on the d rift flux model, using different correlation parameters for bubbly/slug, an d slug or slug/churn flow regimes.