Numerical Analysis of Combustion Oscillation Stabilization by Helmholtz Oscillation Control(<Special Issue>Experimental Mechanics in Heat and Fluid Flow)

Combustion oscillation stabilization by Helmholtz resonator has been investigated for gas turbine combustor, and mechanism of oscillation control has been discussed in terms of analysis model of Helmholtz oscillation, excited between combustor and fuel injector. Amplitude of oscillation pressure is stabilized corresponding to resonator parameters, such as throat diameter and length, and calculated results on combustion oscillation stabilization are compared with experimental results by atmospheric combustion apparatus. In case Helmholtz resonator equipped to combustor is in resonance to combustor chamber, it is shown that amplitude of oscillation pressure can be minimized. However, effectiveness of the resonator may be lessened with decrease of throat diameter or increase of throat length, while throat diameter and length are both tuning parameters of the resonator. Throat resistance, which is determined by both of throat diameter and length, is actually one of the major parameters in Helmholtz oscillation control. Resonator parameters must be optimized in terms of attenuation characteristics as well as resonance frequency.