Microbubble-induced ultrasonic cavitation for ultra-small area radical processing.

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K05215
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 27020:Chemical reaction and process system engineering-related
• Research Institution: Nagaoka National College of Technology
• Principal Investigator: Murakami Yoshinori 長岡工業高等専門学校, 物質工学科, 教授 (70293256)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 超音波 / ラジカル / 微細気泡

Outline of Final Research Achievements

The tubes were connected in series. KI solution flowed through them and they were ultrasonically irradiated. The results of the KI method showed that when irradiated at 45 kHz from the first oscillator, the amount of OH radicals produced increased significantly more than when irradiated by a single oscillator. The amount of OH radicals produced also increased during ultrasound irradiation at 28 kHz and 100 kHz. Furthermore, the results of the titanium sulphate method were similar to those of the KI method. Although ultrasonically irradiated bubbles form bubble agglomerates by the action of the Bjerknes force, the results of this experiment suggest that it is possible to increase the amount of ∙OH produced even if some microbubbles are crushed by ultrasonic irradiation and remain as even finer ultrafine bubbles.

Free Research Field

反応工学

Academic Significance and Societal Importance of the Research Achievements

本研究課題は、これまで報告例がない微細気泡（マイクロバブル）を核あるいは発生源としたこれまで研究例のない新規超音波キャビテーション場の研究例であり、超音波キャビテーションを利用する技術者のみならず、音響キャビテーションの学理研究に携わる研究者においても重要な知見を得る成果となると考えている。