An Experimental Study on the Orifice Nozzle System that Generates Micro-bubbles by Self-suction of Air with a Recirculating Flow

An experimental study was performed on the orifice nozzle system that generates micro-bubbles by air self-suction using a venturi nozzle. This study experimentally investigates the amount of air sucked into the venturi nozzle and the number of micro-bubbles generated by the orifice nozzle system in Cases 1 and 2. The experimental conditions were varied by changing the diameter of the orifice nozzle (d=2~7 mm) and the number of holes of the perforated plate nozzle (n = 2-12). In Case 1, the air self-suction was more than 2 LPM at $d{\leq}4mm$. When d = 4 mm, the total number of bubbles was 29,777, and it was confirmed that micro-bubbles occupied approximately 65% of the total number of bubbles. In Case 2, the air self-suction was maintained constant at approximately 2.5 LPM regardless of the number (n) of holes. The total amount of bubbles increased when n increased but remained constant at approximately 44,000 when $n{\geq}7EA$. It was also confirmed that more than 80% of all bubbles were micro-bubbles when $n{\geq}10EA$. Thus, the number of micro-bubbles increased by approximately 15% compared to the experimental result of Case 1, which was optimized with d = 4 mm.

재순환 유동 공기 자가흡입에 의한 마이크로버블 발생 오리피스 노즐 시스템에 대한 실험적 연구