The swirl reacting flow in a cylindrical vortex combustor is investigated numerically in this work. The model treats the conservation equations of mass, momentum and energy, and species concentration in three dimensions. The numerical algorithm is based on a preconditioned, density-based, finite-volume approach and along with a dual-time stepping integration. One of the most significant and useful phenomena of swirling flows is the generation of recirculation bubble due to vortex breakdown, which plays an important role in flame stabilization. The swirl restricts the flame to expand to the downstream by providing a helical flow, which not only cause the flame to propagate mainly in tangential direction, but also increases the contact with the high-temperature central region. Under the influence of viscous effects on the upstream end, a little amount of fluid penetrated to the central region along the end surface, which not only push the recirculation zone to the downstream, but also reduce the size of this zone greatly. This flow forms another low speed zone between the upstream end and the recirculation zone, which can also serve as the flame anchor by providing a reduced velocity region and an elongated circular flow path. It's found that at a fixed working pressure, as the injecting velocity increases, the flame front is located farther to the downstream. As the working pressure increases, the flame front moves to the upstream for the same injecting velocity. Both the adiabatic and isothermal boundary conditions are considered in this problem. For a small combustor, the surface-dominated effects are striking and the Biot number is small, the isothermal boundary conditions are more reasonable. This isothermal boundary conditions help to preheat the reactants to the ignition point and shorten the flame length. In the downstream, the heat loss from solid wall reduces the temperature of products greatly and makes the recirculation zone lose the function to stabilize flame.
|Number of pages||12|
|Publication status||Published - 2004|
|Event||42nd AIAA Aerospace Sciences Meeting and Exhibit - Reno, NV, United States|
Duration: 2004 Jan 5 → 2004 Jan 8
|Other||42nd AIAA Aerospace Sciences Meeting and Exhibit|
|Period||04-01-05 → 04-01-08|
All Science Journal Classification (ASJC) codes