【摘要】 为研究CO2/O2气氛下黎开(Rijke)型燃烧器的热声不稳定机理,在Rijke型燃烧器热声不稳定特性试验台架上测量了不同燃烧功率Pc(氧化剂流率qox=qo2+qco2为83.3、116.7和150mL/s),不同氧气浓度XO2(25%和30%)和不同化学当量比Φ(0.6、0.7、0.8、0.9和1.0)下的温度分布、燃烧完全性和热声压力脉动特性。Rijke型预混燃烧器下端封闭,上端开口,为直径40mm,管长1066mm的不锈钢圆管。稳燃体位于燃烧器1/4管长处,为致密堇青石材质的多孔介质,CO2/O2/CH4的预混气体在稳燃体上方燃烧。试验发现,Rijke型燃烧器的燃烧温度与Pc和Φ有重要关系,CH4未燃尽率呈现出良好的线性度,随着Φ的增大而减小。CO2/O2气氛下的热声不稳定频率特性与空气气氛下存在明显区别,其共振频率低于空气气氛下的类似工况结果,当qox=83.3或116.7mL/s时,Φ≤0.6的工况不能激发热声不稳定;当qox=150mL/s时,Φ≤0.7的工况不能激发气热声不稳定。更多还原

【Abstract】 The objective of this paper is to study the thermoacoustic instability mechanisms of Rijke-type combustor under the CO2/O2 atmosphere,an experimental setup has been built.Temperature distributions,combustion completeness and thermoacoustic oscillations were investigated under different combustion powers Pc (oxidant flow rate qox:83.3,116.7 and 150 mL/s),oxygen concentrations XO2 (25% and 30%) and equivalence ratios Φ(0.6,0.7,0.8,0.9 and 1.0).A closed-open stainless tube with a diameter of 40 mm and a length of 1066 mm was used as the combustor,and the flame holder made of dense cordierite was mounted in the cross-section at the quarter place downstream of the combustor inlet.The premixed gas of CO2/O2/CH4 was ignited just downstream of the flame holder.Experimental results showed that the temperature inside the combustion chamber was greatly related to the Pc and Φ.The un-burn-off rate of methane decreases with Φ,showing a good linearity.The excitations of thermoacoustic instability differ a lot with the cases under the air atmosphere,their resonant frequencies are lower than those under the air atmosphere.Results showed that the instabilities did not occur when Φ≤0.6 under the condition of qox=83.3 or 116.7 mL/s,and that the instabilities did not occur when Φ≤0.7 under the condition of qox=150 mL/s.更多还原