Characterizing Non-Newtonian Two-Phase Flow in Airlift Pumps

Abstract

Experiments are performed in a recirculating two-phase flow loop using an airlift pump with an axial air injector and at different non-Newtonian rheological behaviours. This was achieved using three mixtures of Xanthan Gum (XG) and water of 0.05 %, 0.15 %, and 0.25 % by weight concentrations. Both air and liquid flow rates are recorded for the desire pump operating conditions. The pump performance found to be directly correlated with the concentrations of XG. The pump flow rates decreased as the XG concentration increased due to the decrease of slug velocity which is responsible for high lifting effect. The recorded slug velocity was found to change between 1.81 cm/s, 1.75 cm/s, and 1.7 cm/s for XG concentrations of 0.05 %, 0.15 %, and 0.25 % respectively. Also, with the increase of XG concentration, the slug length found to increase due to the formation of large slugs without many trailing small bubbles as seen in the lower concentrations' cases. As the viscosity increased for different XG concentrations, the calculated efficiency of the airlift pump found to decrease as well. This is attributed to the fact that as the liquid became more viscous, higher energy of the air is required to overcome the shear stresses acting on the liquid phase to provide lifting.

Investigating Airlift Pump Performance under Three-Phase Flow Conditions

“…Moreover, it is important to mention the drastic decrease in the liquid discharge rates, as seen in Figure 3a. This is a result of the increased slurry density, which highly influences the performance of the airlift pump, as seen in the experiment by Rosettani et al [11]. As mentioned before, the liquid in a three-phase flow is the carrying medium.…”