A Solution for Noise Associated With a Series Staged DLE Combustion System

Over recent years, Rolls-Royce has been at the forefront of the development of low emissions combustion technology in the industrial aero-derivative gas turbine marketplace. The solution developed embodies dry low emissions (DLE) combustion. However, this lean burn technology carries with it the inherent issue of acoustic resonance i.e. combustion noise. This paper will discuss the Rolls-Royce solution adopted for the Industrial RB211 to control the noise issues associated with DLE combustors whilst consistently achieving less than 25vppm NOx emissions. The author discusses the problems associated with DLE emissions and details the history of the RB211 DLE solution from the initial ‘biased primary’ fuelling to the current active noise control system that embodies a ‘short combustor’ with a ‘variable split secondary’ fueling system. Finally, by discussing development results and in-field experience since the new product development, the full capability and flexibility of this solution will be demonstrated.