Transactions of the Korean Society of Mechanical Engineers B (대한기계학회논문집B)

The Korean Society of Mechanical Engineers (대한기계학회)
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An Investigation on Dynamic Behaviors of Single Vortex with CO2 Dilution in a CH4-Air Jet Diffusion Flame

CH4공기 제트 확산화염에서 CO2 첨가에 따른 단일 와동의 동적거동에 관한 연구

  • 황철홍 (인하대학교 대학원 기계공학과) ;
  • 오창보 (인하대학교 대학원 기계공학과) ;
  • 이대엽 (인하대학교 기계공학과) ;
  • 이창언 (인하대학교 기계공학과)
  • Published : 2003.09.01
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Abstract

The dynamic behaviors of the single vortex interacting with $CH_4-Air$ jet diffusion flame are investigated numerically. The numerical method is based on a predict-corrector scheme for a low Mach number flow. A two-step global reaction mechanism is adopted as a combustion model. Studies are conducted in fixed initial velocities for the three cases according as where $CO_2$ is added; (1) without dilution, (2) dilution in fuel stream and (3) dilution in oxidizer stream. A single vortex is generated by an axisymmetric jet, which is made by an impulse of a cold fuel when a flame is developed entirely in a computational domain. The simulation shows that $CO_2$ dilution in fuel stream results in somewhat larger vortex radius, and greater amount of entrainment of surrounding fluid than in other cases. Thus, the dilution of $CO_2$ in fuel stream enhances the mixing in single vortex and increases the stretching of the flame surface. The budgets of the vorticity transport equation are examined to reveal the mechanism of vortex formation when $CO_2$ is added. It is found that, in the case of $CO_2$ dilution in fuel stream, the vortex destruction due to volumetric expansion and the vortex production due to baroclinic torque are more dominant than in other cases.

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References

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