Performance Improvement of Swirl Type Micro Bubble Generator

(2^nd Report: Effect of Inlet Diameter of Swirl Chamber on Bubble Diameter by Analysis)

Abstract

Micro bubbles measuring tens of micrometers or less in diameter have recently been paid much attention. Swirl-type, pressurizing dissolution, and perforated plate methods have been proposed for micro bubble generation. The swirl-type method can generate micro bubbles even under low-pressure power in a simple structure. The enlarged inlet diameter of the swirl chamber can reduce the average bubble diameter. This study examined the effect of the swirl chamber inlet diameter on the flow around chamber outlet in a swirl-type micro bubble generator by numerical analysis. The Inlet diameter of the swirl chamber was changed to 30 mm, 60 mm, and 90 mm, the flow velocity distribution and the wall shear stress around the chamber outlet were calculated. As a result, when the inlet diameter of the swirl chamber was enlarged, it was clarified that the circumferential flow velocity and the wall shear stress around the chamber outlet increased, which reduced the average bubble diameter.