Gas-liquid swirling flow behaviors and liquid-carrying mechanism inside a horizontal pipe

The behaviors of gas-liquid swirling flow under various swirler turns, neglected in previous studies, are essential for swirling flow applications. The role of swirler turns (1, 3, 5) in swirling flow characteristics was systematically investigated in a horizontal pipeline with an inner diameter of 32 mm. The temporal stability and circumferential symmetry of swirling liquid film become better with increasing swirler turns. The periodicity of the swirling liquid film interfacial wave induced by slug flow increases as the swirler turns decrease, while the main wave frequency decreases. Interestingly, for the original slug flow, the downstream void fraction probability density function curves are bimodal with 3 and 5 turns, while it is single-peaked at the swirler with 1 turn. The effectiveness of swirler with 1 turn, 3 turns, and 5 turns in promoting carrying liquid was 100 %, 82.08 %, and 89.22 %, respectively. The mechanism of liquid-carrying was explained in terms of perturbation waves and momentum transfer in the gas-liquid interface. Based on the homogeneous flow model and separated flow model, two predictive models for swirler pressure loss were proposed with maximum errors of 14.67 % and 17.86 %, respectively.