Abstract: The central recirculation zone (CRZ) in a swirl
stabilized gas turbine combustor has a dominant effect on the fuel air
mixing process and flame stability. Most of state of the art swirlers
share one disadvantage; the fixed swirl number for the same swirler
configuration. Thus, in a mathematical sense, Reynolds number
becomes the sole parameter for controlling the flow characteristics
inside the combustor. As a result, at low load operation, the
generated swirl is more likely to become feeble affecting the flame
stabilization and mixing process. This paper introduces a new swirler
concept which overcomes the mentioned weakness of the modern
configurations. The new swirler introduces air tangentially and
axially to the combustor through tangential vanes and an axial vanes
respectively. Therefore, it provides different swirl numbers for the
same configuration by regulating the ratio between the axial and
tangential flow momenta. The swirler aerodynamic performance was
investigated using four CFD simulations in order to demonstrate the
impact of tangential to axial flow rate ratio on the CRZ. It was found
that the length of the CRZ is directly proportional to the tangential to
axial air flow rate ratio.