Question

Air is injected into a 50 m long horizontal pipeline (of 42 mm diameter) carrying a clay slurry of density 1452 kg/m 3 . The rheological behaviour of the slurry follows the power-law model, with m = 5.55 Pa sn and n = 0.35. The volumetric flow rates of air and liquid are 7.48 and 1.75 m3 /h, respectively. The air is introduced into the pipeline at 20°C and at a pressure of 1.2 bar. Ascertain the flow pattern occurring in the pipeline. Estimate (a) the average liquid holdup at the midpoint, (b) the pressure gradient for the two phase flow, (c) the maximum achievable drag reduction and the air velocity to accomplish it

Answer 1