Phase-Space Description of Unstable Dynamics of a Lean Premixed Gas Turbine Combustor

This work describes unstable phenomena of a lean premixed gas turbine combustor by considering the geometrical properties of their phase space representation. Several experiments were performed in which the air excess ratio  and the percentage of pilot fuel PFP were varied. The time series of experimentally measured pressure and heat release fluctuations inside the duct were described using vectors collecting topological parameters of the attractors of experimental acoustical and optical signals. Therefore, unsupervised Kohonen associative memories were trained to create clusters of operating conditions characterised by similar dynamical behaviours. The results of the clustering underline the practical possibility of defining an algorithm for instability pattern recognition, which could be effective for the design of either a diagnostic or a control system.