질소로 희석된 프로판 동축류 층류 제트 부상화염에서 동축류 속도에 따른 열손실에 의한 자기진동 특성 = Effect of Coflow Jet Velocity On Heat-loss-induced Self-excitation in Laminar Lifted Propane Coflow-Jet Flames Diluted with Nitrogen

다국어 초록 (Multilingual Abstract)

The current study was motivated by reasoning why heat-loss-induced self-excitation, identified well in laminar lifted free-jet flames, has not been so far observed in lifted coflow jet flames. Concerning a well-defined heat-loss-induced self-excitation at zero coflow velocity, experiments were conducted by varying coflow velocity until heat-loss-induced self-excitation disappears. It was found that there exists a limit coflow velocity over which heat-loss-induced self-excitation does not occur, i.e, the coflow velocity 40 ㎝/s for the nozzle diameter 0.3 ㎜ in the current study. Based on this, flame stability maps were presented in the coflow velocity ranges of 10 ~ 40 ㎝/s. The functional dependency of Strouhal number upon related parameters is described for the heat-loss-induced self-excitation and discussed in detail.
An newly identified oscillating by flame extinction (mode Ⅱ) is shown to be realted to the heat-loss-induced self-excitation from premixed wings to trailing diffusion flame in the current laminar lifted coflow jet flames; meanwhile the traditional flame blow-out (mode Ⅰ) as well as the heat-loss-induced blow-out (mode Ⅱ) have been so far found in laminar lifted free jet flames. It is seen that the flame blow-out of the mode Ⅱ is delayed compared to that in laminar lifted jet flame. The oscillating by flame extinction (mode Ⅱ) is discussed in detail for the relevance with the coflow velocity.

목차 (Table of Contents)

• ABSTRACT
• 1. 서론
• 2. 실험 방법
• 3. 결과 및 검토
• 4. 결론
• 후기
• 참고문헌