Abstract
A turbulent lifted slot-jet flame is studied using direct numerical simulation (DNS).
A one-step chemistry model is employed with a mixture-fraction-dependent activation energy which can reproduce qualitatively the dependence of laminar burning rate on equivalence ratio that is typical of hydrocarbon fuels. After first describing the overall flame structure, the statistics of flow and relative edge-flame propagation velocity components conditioned on the leading-edge locations are examined. The results show that,on average, the streamwise flame propagation and streamwise flow balance, thus demonstrating that edge-flame propagation is the basic stabilization mechanism. Fluctuations of the edge locations and net edge velocities are, however, signicant. It is demonstrated that the edges tend to move in an essentially Two-Dimensional elliptical pattern (starting from a downstream location, laterally outwards towards the oxidizer, then upstream, then inwards towards the fuel, then downstream again). It is proposed that this is due to the passage of large eddies, which is mostly consistent with the picture outlined in Su et al. (2006).
A one-step chemistry model is employed with a mixture-fraction-dependent activation energy which can reproduce qualitatively the dependence of laminar burning rate on equivalence ratio that is typical of hydrocarbon fuels. After first describing the overall flame structure, the statistics of flow and relative edge-flame propagation velocity components conditioned on the leading-edge locations are examined. The results show that,on average, the streamwise flame propagation and streamwise flow balance, thus demonstrating that edge-flame propagation is the basic stabilization mechanism. Fluctuations of the edge locations and net edge velocities are, however, signicant. It is demonstrated that the edges tend to move in an essentially Two-Dimensional elliptical pattern (starting from a downstream location, laterally outwards towards the oxidizer, then upstream, then inwards towards the fuel, then downstream again). It is proposed that this is due to the passage of large eddies, which is mostly consistent with the picture outlined in Su et al. (2006).
| Original language | English |
|---|---|
| Title of host publication | Studying Turbulence Using Numerical Simulation Databases - XV |
| Subtitle of host publication | Proceedings of the 2014 Summer Program |
| Editors | Parviz Moin, Javier Urzay |
| Place of Publication | Stanford CA USA |
| Publisher | Stanford University Press |
| Pages | 137-146 |
| Number of pages | 10 |
| Publication status | Published - 2014 |
| Externally published | Yes |