An investigation on the effect of open hole number and scheme on single-phase flow of a swirl flow bubble generator

A swirl flow bubble generator with a unique adjustment scheme was developed to adapt to liquid feed flow rate variation. However, a study on the scheme and flow field of the bubble generator has not been reported in the literature. Particle image velocimetry and computational fluid dynamics were utilized to explore the flow field and adjustment scheme. The results showed that the standard k-ε model could more accurately describe the flow pattern than other turbulence models, and the pressure drop difference between experiments and simulations was less than 6%. A mathematical expression was established to quantitatively describe the relationship among the pressure drop, open hole number, and liquid flow rate. The pressure drop was proportional to the feed flow rate or inlet velocity square and inversely proportional to the power of 1.86 of the open hole number. Interestingly, the pressure drop of different open hole schemes with the same open hole number of 12 was close to 55 kPa. The spiral-bottom open hole schemes could provide a higher turbulent dissipation rate for both the vortex chamber and straight pipe section. This work can guide the bubble generator adjustment and fill the gap in this respect.