Acoustical and optical investigations of an atmospheric hydrogen RQL combustor

The thermoacoustic behavior of a non-premixed, industrial RQL-type combustor operated with hydrogen is investigated experimentally. Flame transfer functions (FTF) are obtained utilizing the multimicrophone method, aiming to quantify the acoustic response of the swirl-stabilized hydrogen diffusion flame to pressure perturbations from either the primary combustion air passing through the burner itself, or the dilution air pathway. Flame images are captured using OH*-chemiluminescence and analyzed in terms of shape and intensity distribution. The basis of the experimental investigation is formed by a sweep in fuel-air ratio (FAR) at two different preheating temperatures with constant primary and secondary air mass flows, accompanied by the assessment of additional parameters.