Transactions of the Korean Society of Mechanical Engineers B (대한기계학회논문집B)
- Volume 21 Issue 11
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- Pages.1527-1537
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- 1997
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- 1226-4881(pISSN)
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- 2288-5324(eISSN)
DOI QR Code
Numerical study on extinction and acoustic response of diluted hydrogen-air diffusion flames with detailed and reduced chemistry
상세 및 축소 반응 메커니즘을 이용한 희석된 수소-공기 확산화염의 소염과 음향파 응답 특성에 관한 수치해석
- Son, Chae-Hun (Dept.of Mechanical Engineering, Graduate School of Seoul National University) ;
- Jeong, Seok-Ho (Dept.of Mechanical Engineering, Seoul National University)
- Published : 1997.11.01
Abstract
Extinction characteristics and acoustic response of hydrogen-air diffusion flames at various pressures are numerically studied by employing counterflow diffusion flame as a model flamelet in turbulent flames in combustion chambers. The numerical results show that extinction strain rate increases linearly with pressure and then decreases, and increases again at high pressures. Thus, flames are classified into three pressure regimes. Such nonmonotonic behavior is caused by the change in chemical kinetic behavior as pressure rises. The investigation of acoustic-pressure response in each regime, for better understanding of combustion instability, shows different characteristics depending on pressure. At low pressures, pressure-rise causes the increase in flame temperature and chain branching/recombination reaction rates, resulting in increased heat release. Therefore, amplification in pressure oscillation is predicted. Similar phenomena are predicted at high pressures. At moderate pressures, weak amplification is predicted since flame temperature and chain branching reaction rate decreases as pressure rises. This acoustic response can be predicted properly only with detailed chemistry or proper reduced chemistry.
Keywords
- Hydrogen-Air Diffusion Flames;
- Extinction;
- Strain Rate;
- Acoustic Response;
- Detailed/Reduced Chemistry
- 수소-공기 확산 화염;
- 소염;
- 스트레인율;
- 음향파 응답;
- 상세/축소 화학 반응;