| 摘要: |
| 为了设计火焰更加稳定的燃烧器,需要对导致火焰不稳定的机理开展研究。通过在钝体外侧通环形空气流,中心通燃料得到钝体稳燃非预混火焰。借助平面激光测速仪、增强型光电耦合器等测量手段,对两类不稳定火焰——不稳定脱离火焰和分离闪烁火焰的流动和反应区分布进行了测量,分析了导致两类不稳定火焰机理。结果发现,中心燃料和空气雷诺数的相对大小不同的情况,进入回流区内的燃料量的差异,是导致出现不同不稳定火焰模态的重要机制。因此为了得到稳定的钝体燃烧器中心射流火焰,需要合理安排流场使得回流区内燃料浓度合理。 |
| 关键词: 钝体 非预混火焰 不稳定性 机理 实验研究 |
| DOI： |
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| Experiments on Mechanisms of Unstable Flames in Bluff-Body Burner with a Central Fuel Jet |
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TANG Hao-jie, ZHENG Yun-zhe, ZHANG Tong-feng, ZHU Min
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(Deportment of Thermal Engineering/Key Laboratory for Thermal Science and Power Engineering of Ministration of Education, Tsinghua University, Beijing 100084, China)
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| Abstract: |
| The mechanisms inducing unstable flames should be investigated to help designing stable burners. Bluff-body stabilized non-premixed flames were obtained by arranging the annular air flow outside the bluff-body and fuel jet flow in the center. By means of Intensified Charge Coupled Device(ICCD) and Particle Image Velocimetry(PIV), the flow fields and the reaction zones of the two unstable flame modes, unsteady detached flame and split-flashing flame, were measured. The fundamental mechanisms were analyzed. The quantity of fuel entering the recirculation zone is an important factor that results in the two unstable flames at different flow conditions. As the conclusion, it is of great significance to arrange the flow field reasonably for proper fuel concentration in the recirculation zone in order to obtain stable flames. |
| Key words: Bluff-body Non-premixed flame Instability Mechanism Experimental investigation |
