Comparison and extension of methods for acoustic identification of burners

摘要: Abstract The prediction and the control of combustion instabilities require identification chamber response. This is usually performed by forcing combustor (for example, modulating its inlet velocity) measuring Two methods may be found in literature to analyze this response: transfer matrices (ITM) flame functions (FTF). In ITM approaches, burner considered as a “black box” two-port formulation (based on acoustic pressure velocity perturbations) used construct matrix linking fluctuations both sides burner. A drawback method that experiments, measurement unsteady burnt gases can difficult. FTF measurements are replaced global heat release (usually based optical methods). then related flow modulations at reference point inlet) through function. paper uses compressible numerical simulation forced laminar Bunsen methods. Results show approaches lead an ill-defined problem soon not close enough chamber. “compactness” limit quantified here terms distance between local source correlate oscillations only: extended models proposed using well upstream predict oscillations. These tested numerically provide consistent values when location changes or downstream conditions varied. results simple recommendations for system identification.