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Abstract

In this work longitudinal and transverse combustion instabilities are studied in two types of configurations. While longitudinal modes have been observed in many previous studies at low frequencies, the present work also focusses on high-frequency transverse modes. First, a premixed flame stabilized on a V-flame holder is investigated where experimental results obtained by Volvo are used to validate the simulations. For different operating conditions, longitudinal and transverse modes are observed in Large Eddy Simulations (LES) and show good agreement with the experimental data in terms of pressure frequency and flow dynamics. In a second step, a semi-industrial case is examined within the European project KIAI. Experiments are conducted by ONERA and LES of this two-phase flow configuration (called Lotar) are carried out. Transverse combustion instabilities are analyzed and key elements which drive instabilities are identified. These observations are used to reformulate the classic Flame Transfer Function (FTF) in order to predict the stability of transverse modes by use of an Helmholtz solver. The results reproduce fairly well the stability map generated by LES.

Jury