Determination of the heat conduction transfer function within the thermoacoustic instability limit cycle in a Rijke tube

In this work, experimental measurements of the heat conduction transfer function (HCTF) within the limit cycle of thermoacoustic instabilities were conducted associated with a feedback controller. The responses of the heat conduction from the heater to the air in the vicinity to the oncoming flow disturbance can be described as the HCTF. When self-excited thermoacoustic instability occurs, it is not possible to measure the HCTF. The measurement experiment is twofold. Firstly, the active feedback control is applied to suppress the self-excited thermoacoustic oscillation in the Rijke tube. Secondly, the two-microphone method is applied to achieve the measurement of the HCTF at different working conditions. Experimental results show that the mean air flow velocity has an effect on the attenuation time of the thermoacoustic oscillation. Both of the mean air flow velocity and the electric-heating power have a significant effect on HCTFs.