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环形模型燃烧室内不同Karlovitz数旋流预混火焰的直接数值模拟 被引量:1
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作者 肖华林 罗坤 +2 位作者 王海鸥 金台 樊建人 《空气动力学学报》 CSCD 北大核心 2020年第3期611-618,共8页
为了更好地理解航空发动机燃烧室内的旋流预混燃烧现象和机理,基于相关特征参数采用直接数值模拟方法研究了模型燃烧室内的旋流预混火焰。其中计算模型简化自环形燃烧室,包含两个相邻的贫燃旋流,参数尽可能接近实际航空发动机燃烧室工... 为了更好地理解航空发动机燃烧室内的旋流预混燃烧现象和机理,基于相关特征参数采用直接数值模拟方法研究了模型燃烧室内的旋流预混火焰。其中计算模型简化自环形燃烧室,包含两个相邻的贫燃旋流,参数尽可能接近实际航空发动机燃烧室工况。模拟中,采用了简化的煤油反应机理,设计了不同Karlovitz数(Ka)对应高低两种负荷。结果表明,在高压下火焰面极薄,小尺度湍流扰动对火焰面影响显著,燃烧室内湍流预混火焰位于薄反应区。在下游由于相邻旋流的作用而产生较为破碎的火焰结构,这一现象在高Ka时尤为明显。雷诺数Re和Ka较大时,旋流剪切作用所导致的下游中心回流效应增强,剪切层中的湍流扰动效应也更强。航空发动机燃烧室内主要反应物和生成物基本满足梯度输运关系,且在Ka较大时,梯度输运效应更显著。然而对于中间产物,梯度扩散假设在火焰面附近不成立,这对基于梯度扩散假设的相关计算模型提出了挑战。 展开更多
关键词 直接数值模拟 航空发动机燃烧室 旋流预混燃烧 karlovitz 梯度扩散
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Asymptotic Analysis of Transport Properties and Burning Velocities for Premixed Hydrocarbon Flames
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作者 J.Y.Law H.K.Ma 《Journal of Thermal Science》 SCIE EI CAS CSCD 2001年第2期170-175,共6页
Based on premixed flame, the theoretical model of transport properties with temperature variation was established inside a preheated zone. Lewis number of the deficient-to- stoichiometric hydrocarbon/air mixture has b... Based on premixed flame, the theoretical model of transport properties with temperature variation was established inside a preheated zone. Lewis number of the deficient-to- stoichiometric hydrocarbon/air mixture has been theoretically predicted over a wide range of preheated temperature. These predictions are compared with the experimental data on disport properties that exist in the literature. The response of the burning velocity to flame stretch can be parameterized by the laminar flame speed and Markstein length. Therefore, if the laminar flame speed and Markstein number could be accurately simulated by using an analytic expression of characterized temperature, equivalence ratio, and Lewis number, the results are applicable to the prediction of methane, acetylene, ethylene, ethane, and propane flames. Expanding previous studies on the extinction of premixed flames under the influence of stretch and incomplete reaction, the results were further classified and rescaled. Finally, it could be inferred that parameter Pq, the rescaled extinction Karlovitz number could be used to explain the degree or flame quench. 展开更多
关键词 Lewis number laminar flame speed burning velocity Markstein number karlovitz number.
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