Active Control of Oscillations in Simulations of Gas-Turbine Combustors

Abstract : The approach to extinction of a premixed methane-air flame stabilized behind a plane sudden-expansion gave rise to cyclic movement of the position of flame stabilization with a period of the order of 100 ms. These oscillations have been quantified in terms of simultaneous measurements of pressure and light emission, and the pressure maximum corresponded to the flame position closest to the step and the minima to that furthest away. The active control strategy of imposing out-of-phase oscillations was unsuccessful since the period of the near-limit cycles varied over a substantial range and a new approach will be required to track the signal and to implement online actuation that will counteract the tendency for flame movement.