Development of micro soap bubble generator for PIV tracer using home stereolithography 3D printer

Abstract

A micro soap bubble generator for tracers for PIV measurement was developed using a home stereolithography 3D printer. The nozzle has a coaxial triple pipe structure, and an orifice cap is attached to the nozzle head. The inner diameter of the central pipe is 0.7 mm, and the wall thickness of the central pipe is 0.7 mm. From the comparison of the smoke wire visualization result of the flow around the cylinder placed under the mainstream flow velocity of 3 m/s and the PIV measurement result, it was confirmed that the generated micro soap bubbles have good followability to the flow. Generated bubbles’ particle size was estimated to be Φ0.2 mm at the minimum and Φ6.3 mm at the maximum. The most common was Φ0.9 mm ± 0.1 mm, accounting for more than 50% of the total.