Numerical analysis on combustion flow characteristics of jet-stabilized combustor with different geometry

Abstract

In this study, three novel jet-stabilized combustor geometries with cavity, vertical ring and vertical pipe are respectively proposed, the combustion and emission characteristics are numerically investigated and compared with the original geometry. The realizable k−ε model and presumed probability density functions (PDF) model are used for turbulent combustion, and the nitrogen oxide (NOx) formation model is used for nitric oxide (NO) emission. The results show that two vortex pairs formed in primary zone under four cases, but for the combustor with vertical ring, a vortex pair also appears downstream of air jet holes. For the combustor with vertical pipe geometry, the right-side vortex pair is the biggest, meanwhile the extrusion effect on the left vortexes is obvious. The high-temperature zone is mainly located in the primary zone and downstream of air jet holes for all cases, while the combustor with vertical ring have the smallest high temperature region, and it with a uniform temperature distribution. The outlet temperature distribution factor is lower than 0.036 for all combustors. Compared with the original combustor, the NO emission of combustors with cavity and vertical ring decrease respectively by 31% and 52%, while the NO emission of combustor with vertical pipe increases by 32%.

Keywords

• Jet-stabilized combustor
• Vortex structure
• NO emission
• Combustion flow
• Numerical simulation