16. Uluslararası Yanma Sempozyumuna (16th International Combustion Symposium – INCOS 2022, Aydın, Turkey, 8 - 11 September 2022, vol.1, no.1, pp.1-7
The relationship between air-fuel mixture inlet velocity and flame propagation speed is of great importance for anchoring the flame to the burner lip in a stable manner. In order to achieve this flame stabilization, recirculation bubbles that occur in swirling flows inherently are used. However, these recirculation zones may not always ensure flame stability, and flame instabilities may arise. The aim of this study is to examine the effects of swirl number and equivalence ratio on dynamic behavior of 30%H2 30%CO 20%CO2 20%CNG mixture in a laboratory scale-premixed combustor. For this purpose, such mixture was tested at 2 different equivalence ratios (Φ) and 7 different swirl numbers (SN). In addition, the mixture flames were forced thermo-acoustically by two identical loudspeakers located downstream of the combustion chamber and placed on both sides symmetrically. Dynamic behavior of the flame was determined by measuring static and dynamic pressure, luminosity intensity and instantaneous flame images. As a result of the thermo-acoustic forcing, all tested flames flashed back at forcing frequencies related to natural acoustic modes of the combustor irrespective of the swirl number and equivalence ratio. However, back pressure value in burner varied depending on both parameters.