Computational Fluid Dynamics Simulation Assessment of Inlet Configuration Influence on Enhancing Swirl Flow Microbubble Generator Performance

In this study, a CFD simulation analysis was used to predict the characteristics of a swirl flow as a reference to optimize a new design of microbubble generator. To examine the impact of the inlet design, three different configurations of the inlet type were applied, namely single inlet, double inlet, and tangent-circle inlet. The performance of the microbubble generator was characterized in terms of swirl velocity, pressure drop in radial position, and pressure distribution along the central axis of the microbubble generator. Generally, the CFD analysis succeeded to visualize the hypothetical bath of the flow streamlines inside the microbubble generators. The results illustrated that the swirl flow in the tangent-circle inlet was able to generate a negative pressure zone in the central area of the generator (i.e., self-suction mechanism). In addition, the tangent-circle inlet showed a high-pressure drop compared with the single inlet microbubble generator. Although the double inlet microbubble generator illustrated a high-pressure drop between the inlet and the outlet, the streamlines distribution was focused only on the top part of the microbubble generator. This was a reason why the self-suction mechanism was not well defined.