Sharif Digital Repository

This thesis is a complementary experimental and theoretical investigation on stability of premixed flames and a study of combustion instability and combustion dynamics in a swirl-stabilized combustor, aiming to understand the fundamental mechanisms responsible for combustion oscillations in gas turbine combustors. Theoretical investigations on acoustic modeling of a simple combustor and a study on kinematic response of premixed flames to flow perturbations have been discussed in the first part of this work. In another part of thesis, experimental studies on the response of premixed flames to acoustic perturbations have been performed. In addition, experimental investigations on combustion... 

Low emissions combustion V-flame combustors are exceptionally prone to combustion instabilities. These systems for land based gas turbines rely on a premixed or partially premixed combustion process. As V-flames do not anchored on the lip of combustor, an experimental study of the transfer function of these flames shows that they are more sensitive to fuel oscillations and in the range of frequencies, they behave like an amplifier. This paper presents an experimental study of the transfer function of a ducted, laminar, premixed V and M-flames. V-flame, laminar, propane/air premixed flame stabilised at the rim of the burner. The limit of M and V-flame are identified without excitation, then...