Experiments on the amplification of self-excited thermoacoustic oscillations by suppressing generations of higher harmonics

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K17978
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Fluid engineering
• Research Institution: Fukui University of Technology
• Principal Investigator: SHIMIZU Dai 福井工業大学, 工学部, 准教授 (40448048)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 熱音響自励振動 / ヘルムホルツ共鳴器列 / 熱音響孤立波 / 熱音響ソリトン / 高次振動モード / 衝撃波 / エネルギーカスケード

Outline of Final Research Achievements

Experiments are performed to generate self-excited thermoacoustic oscillations of higher amplitude by suppressing generations of higher harmonics. At the outset, the generations of thermoacoustic standing waves in a straight tube with closed ends are performed. It is found that, by connecting an array of Helmholtz resonators near the middle of the straight tube locally so as to annihilate the second harmonics, the amplitude of excess pressure grows more than 30 percent relative to the one without connecting the resonators. Next, the generations of thermoacoustic traveling waves in looped tubes are demonstrated. It is found that thermoacoustic traveling waves can be increased by locating a pair of resonators in point symmetry. It is also unveiled that a thermoacoustic solitary wave generates spontaneously and propagates endlessly in the looped tube by connecting an array of Helmholtz resonators throughout the tube.

Free Research Field

熱流体工学