Numerical Simulation of Inverse Diffusion Combustion and Flow Characteristics in a Trapped Vortex Combustor
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ORIGINAL PAPER
Numerical Simulation of Inverse Diffusion Combustion and Flow Characteristics in a Trapped Vortex Combustor Haijun Sun1
· Pinghua Yan2 · Le Tian1 · Yihua Xu1
Received: 2 January 2020 / Revised: 25 October 2020 / Accepted: 30 October 2020 © The Korean Society for Aeronautical & Space Sciences 2020
Abstract In this work, the cold and combustion flow characteristics of a trapped vortex combustor with inverse diffusion combustion method have been studied numerically, and the effects of four jet arrangement schemes on the vortex structure, temperature distribution, turbulence kinetic energy, OH mass fraction and combustion efficiency were compared. The results indicate that the vortex structures in cold state are basically the same with a double vortex structure for all the jet schemes. However, when the jet holes are arranged on the after-body wall, the vortex changes from a double vortex structure in cold state to a single vortex structure in combustion state, the combustion effect is not too large when the jet holes are arranged on the fore-body wall. The high-temperature distribution in cavity is mainly concentrated in the upper part, but when the jet holes are arranged on the after-body wall, the OH mass fraction distribution is higher than that when the jet holes are arranged on the fore-body wall. In addition, when the jet holes are arranged on the fore-body wall, complete combustion can be accelerated. In general, when the jet holes are arranged in the same position, the multi-jet scheme is more conducive to flame stability in cavity and the improvement of combustion and mixing performance than the coaxial jet. Keywords Trapped vortex combustor · Numerical simulation · Vortex structure · Multi-jet
List of Symbols A C1 , C2 C g , Cd Di,m E f −− f 2
Gk h Ji
B
Area Turbulence model constants Reaction model constants Mass diffusion coefficient Total energy Mean mixture fraction Variance of mixture fraction Generation of turbulence kinetic energy due to the mean velocity Enthalpy The diffusion flux of species
Haijun Sun [email protected]
1
Jiangxi Key Laboratory of Micro Aero-Engine, School of Aircraft Engineering, Nanchang Hangkong University, Nanchang 330063, China
2
College of Artificial Intelligence, Jiangxi College of Application Science and Technology, Nanchang 330100, China
keff k Mi m˙ p p( f ) p( f , h) SE Sct Sh Si j Yj
Effective conductivity Turbulence kinetic energy Molecular weight of species Mass flow rate Static pressure Probability density function Joint probability density function Heat source term of chemical reaction Turbulent Schmidt number Source terms due to radiation, heat transfer to wall boundaries Mean rate strain tensor Mass fraction of the species j
Greek Symbols ρ τ u, v μt i ε
Density Stress tensor Velocity component Turbulent viscosity Volumetric rate of creation of species i Dissipation rate of turbulence kinetic energy
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International Journal of Aeronautical and Space Sciences
σk , σε σt ηc η φi
Turbulent Prandtl numbers Reaction model consta
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