The flow and combustion behaviors of confined swirling flames with liquid fuels are of technical and fundamental interest. The rotation induced by these devices generates a central recirculation zone (CRZ) and, in many cases, an outer recirculation zone filled with hot combustion products, which serves as a continuous ignition source to stabilize the flame. In a swirling combustor, the flame is anchored by imparting an azimuthal component to the flow (usually by passing the airstream through a swirler). Due to their excellent performance in terms of ignition and flame stabilization, swirling flames are widely used in modern gas turbine combustors. One of the most important parts of an aircraft gas turbine is the combustor, which increases the thermal energy of a stream of moving air through combustion. Finally, a sketch map on the space of mixture fraction and combustion efficiency was proposed to understand the mixing and oxidization experiences of the fuel mixture. Most of the fuel was found to be oxidized in the primary zone and the intermediate zone however, the slow oxidization reactions also play a non-negligible role on the whole combustion process.

However, partially premixed combustion still appears on the flame base. Furthermore, the combustion process exhibits a mixing-controlled feature in total. Thus, the combustion properties in each sub-zone were dominated by the mean flow structures. In general, the residence time of the fuel-mixture is much longer than both the chemical time scale and the mixing time scale. The time-scale analysis was carried out to understand the combustion modes inside the combustor. The flow and combustion fields show strong self-similarity except on the slow auto-ignition in the mixing layer between fuel-rich product and fresh air upstream of the flame stabilization position. The mixing and combustion processes under different reference velocities in a gas turbine combustor were numerically investigated using the Flamelet Generated Manifold (FGM) model based on the Reynolds Averaged Navier–Stokes (RANS) method.

Laminar flow diffuser