黎开预混燃烧器热声不稳定的试验研究

为探索燃烧过程中热声不稳定的产生机理，搭建了黎开(Rijke)预混燃烧器热声不稳定研究试验台架，并进行了试验研究。Rijke预混燃烧器为直径40 mm，管长1066 mm的不锈钢圆管，下端封闭，上端开口；致密堇青石材质的多孔介质稳燃体位于燃烧器四分之一管长处，甲烷与空气的预混气体在稳燃体上方燃烧形成平面火焰作为加热热源。试验发现，化学当量比f 对Rijke预混燃烧器内热声不稳定的强度有重要的影响，维持Rijke预混燃烧器持续燃烧的下限极限化学当量比和上限极限化学当量比分别为0.63和1.75。另外，试验发现了预混燃烧器内热声不稳定的最大强度并非发生在f=1.0时，而是在f=1.30左右；并且当1.0￡f ￡1.5时，预混燃烧器内的热声不稳定均维持较高的强度。

Experimental Study of Thermoacoustic Instability in Premixed Rijke Combustor

In order to probe into the mechanism of the excitation of thermoacoustic instability in the process of combustion, experimental setup was built to study the thermoacoustic phenomenon in the premixed Rijke combustor. A closed-open Rijke combustor with 40 mm in diameter and 1066 mm in length was used. The flame holder made of dense cordierite was installed in the quarter of the combustor. The premixed gas of methane and air was ignited just downstream of the flame holder to form a flat flame. Experimental results show that the equivalence ratio f has a significant effect on the intensity of thermoacoustic instability. In order to sustain the combustion in the Rijke combustor, the inferior and superior limit of the equivalent ratio was 0.63 and 1.75 separately. The largest intensity of thermoacoustic instability occurrs when f at about 1.30 other than 1.0. The intensity of thermoacoustic instability maintains at a relatively large level when f at the range of 1.0~1.5.