气体入口流量低频脉冲对燃烧稳定性的影响

Effects of low frequency pulse of gas inlet flowrate on combustion stability

中文关键词: 气体射流  脉冲流量  非预混燃烧  时频特性  燃烧稳定性

英文关键词: gas jet  pulse flowrate  non-premixed combustion  time frequency characteristics  combustion stability

中文摘要:

      外部运行因素变化会导致不稳定燃烧现象的发生,严重时甚至引发燃烧室结构损毁。在甲烷与空气 当量比为1条件下以非预混燃烧火焰为对象,利用动态压力传感器及光栅光谱仪测量压力与热释放率的变 化,通过实验研究气体入口流量低频脉冲(1.000~5.000Hz)对燃烧稳定性的影响。结果表明入口流量脉冲 影响燃烧的稳定性,其中火焰形态、燃烧室压力(p)和热释放率(qi)等会发生同频周期脉动。脉冲频率在 2.000~2.500Hz范围内对削弱燃烧稳定性影响最大,表现为p和qi 出现高的脉动幅值,而1.000Hz脉冲频 率对削弱燃烧稳定性影响最小;脉冲频率对削弱燃烧稳定性的影响随频率增加逐渐从线性向非线性变化。脉 冲流量越大,p和qi 的脉动幅值越大,燃烧越趋向不稳定燃烧。

英文摘要:

      The change o f external operating factors leads to unstable combustion, and combustion chamber structure can be destroyed in severe cases. The non-premixed combustion flame was taken as the object under the condition that the equivalence ratio of methane to air was1,and the dynamic pressure sensor and grating spectrometer were used to measure the changes of pressure and heat releaserate.Theeffectsoflow-frequency pulseofgasinletflow rate (1.000 ~ 5.000 Hz)on combustionstabilitywereanalyzedexperimentally.Resultsshowthattheinletflowpulseaffectsthe combustionstability.Theflameshape,combustionchamberpressure(p)andheatreleaserate(qi) fluctuateperiodicallyatthesamefrequency.Thepulsefrequency hasthegreatestinfluenceon weakeningcombustionstabilityintherangeof2.000 ~ 2.500 Hz,whenpandqi havehighpulse amplitude.However,1.000 Hzpulsefrequency hastheleasteffecton weakening combustion stability.Theinfluenceofpulsefrequencyonweakeningcombustionstabilitygraduallychangesfrom lineartononlinearwiththeincreaseoffrequency.Itsuggeststhegreatertheproportionofpulse flowrateis,thegreatertheamplitudeofp andqi is,withthecombustiontendingtounstable combustion.