Influence of fuel stage ratio on pressure oscillation frequency of LESS combustor

Influence of fuel stage ratio on pressure oscillation frequency of low emissions with stirred swirls (LESS) combustor was tested. The pressure oscillation frequency dropped with the decrease of fuel stage ratio (from 32.7% to 5.21%) under the combustor inlet pressure of 1.14 MPa to 2.77 MPa, combustor inlet temperature of 645 K to 808 K, total fuel air ratio of 0.0242 to 0.0303 and combustor pressure drop of 3.14% to 3.64%. A homogeneous straight pipe model and CFD numerical method were adopted to analyze the influence of fuel stage ratio on pressure oscillation frequency. The results show that changes of original position, axial length and mean temperature of flame zone caused by fuel stage ratio are the main reasons contributing to the changes of pressure oscillation frequency.