Simulation of an algorithm for the active control of combustion noise

Abstract

The simulation of an algorithm for the active control of combustion noise generated by a turbulent flame produced by an open burner is developed in this thesis. The simulation includes (1) an autoregressive model of real combustion noise, (2) a feedback loop based on the "observer" method, (3) a model of the transfer function between the acoustic driver and the sensor through the flame, and (4) a method to take into account the time-delay due the calculation of the algorithm. A practical implementation of the control strategy is also proposed. An attenuation of up to 40 dB is obtained in the 0 - 3000 Hz band, decreasing with the time-delay required for creation of the feedback signal. The influence of the order of the autoregressive model is studied, and it is shown that better results are obtained by increasing the order. The choices for the location of the activator and for the type of sensor are investigated and discussed. Further analytical research on the method of computing the feedback signal in the presence of time-delay is identified.