TY - GEN
T1 - MODE HOPPING ANALYSIS OF NONLINEAR THERMOACOUSTIC INSTABILITY IN A RIJKE TUBE WITH THE CERAMIC POROUS BURNER
AU - Wang, Abiao
AU - Ji, Chenzhen
AU - Song, Xiuyang
AU - Li, Xinyan
AU - Zhao, Dan
AU - Zhu, Tong
N1 - Publisher Copyright:
© 2023 Proceedings of the International Congress on Sound and Vibration. All rights reserved.
PY - 2023
Y1 - 2023
N2 - Investigations of mode hopping of non-linear thermoacoustic instability were carried out by experimental tests and numerical simulations in this work. A vertical double-open Rijke type combustor in the length of 1200 mm was employed for the thermoacoustic instability experiments, where a ceramic porous burner was set and fueled with the premixed air-methane. By changing the heat power and equivalence ratio, the stability map of the Rijke tube was protracted. In the unsteady region, it was found that the dominant frequency of limit cycle oscillation hopped from about 165 Hz to about 375 Hz when the equivalence ratio descended. The two dominant frequencies were accurately predicted by calculating the acoustic characteristics of the Rijke tube. There were found to just be the first- and second-order eigenfrequencies of the Rijke tube. To further investigate flame dynamics in the mode hopping of thermoacoustic oscillations, the time-averaged and phase-locked flame images were analyzed. When the oscillations occurred in higher dominant frequencies, the time-averaged flames were more compact and attached to the burner, meanwhile, the dominant fluctuation mode of flame was in a blink mode. On the contrary, when the oscillations happened in a lower dominant frequency, the time-averaged flames were longer and lifted from the burner, and the dominant fluctuation mode of the flame was axial pulsation.
AB - Investigations of mode hopping of non-linear thermoacoustic instability were carried out by experimental tests and numerical simulations in this work. A vertical double-open Rijke type combustor in the length of 1200 mm was employed for the thermoacoustic instability experiments, where a ceramic porous burner was set and fueled with the premixed air-methane. By changing the heat power and equivalence ratio, the stability map of the Rijke tube was protracted. In the unsteady region, it was found that the dominant frequency of limit cycle oscillation hopped from about 165 Hz to about 375 Hz when the equivalence ratio descended. The two dominant frequencies were accurately predicted by calculating the acoustic characteristics of the Rijke tube. There were found to just be the first- and second-order eigenfrequencies of the Rijke tube. To further investigate flame dynamics in the mode hopping of thermoacoustic oscillations, the time-averaged and phase-locked flame images were analyzed. When the oscillations occurred in higher dominant frequencies, the time-averaged flames were more compact and attached to the burner, meanwhile, the dominant fluctuation mode of flame was in a blink mode. On the contrary, when the oscillations happened in a lower dominant frequency, the time-averaged flames were longer and lifted from the burner, and the dominant fluctuation mode of the flame was axial pulsation.
KW - Mode hopping
KW - Non-linear
KW - Rijke tube
KW - Thermoacoustic instability
UR - http://www.scopus.com/inward/record.url?scp=85170642997&partnerID=8YFLogxK
M3 - Conference contribution
AN - SCOPUS:85170642997
T3 - Proceedings of the International Congress on Sound and Vibration
BT - Proceedings of the 29th International Congress on Sound and Vibration, ICSV 2023
A2 - Carletti, Eleonora
PB - Society of Acoustics
T2 - 29th International Congress on Sound and Vibration, ICSV 2023
Y2 - 9 July 2023 through 13 July 2023
ER -