Sound emission by non-isomolar combustion at low Mach numbers
Sound emission by non-isomolar combustion at low Mach numbers
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低马赫数下非等摩尔燃烧的声发射
DOI：
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
L. Boyer
中科院分区：
文献类型：
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作者：
Jean;G. Searby;L. Boyer
本文表明，燃烧过程中物质摩尔数的变化对湍流火焰辐射的声功率有很大贡献，不能系统地忽略。从标准守恒方程出发，我们推导出发生低马赫数非等摩尔燃烧的致密流体区域的远场中辐射的声压表达式。在这个公式中，“摩尔”和热膨胀的贡献明确出现。我们还给出了一个公式，其中纯非平稳效应和纯对流效应产生的声发射是独立出现的。作为该理论的应用，我们推导了小火焰状态下预混合火焰发出的声功率。数值评估表明，对于一些常见的碳氢化合物-氧气火焰，摩尔膨胀对声功率的贡献在 2 至 5.6 dB 之间（增加 260%）。
This paper shows that the change in the number of moles of species during combustion can make a strong contribution to the acoustic power radiated by turbulent flames and cannot be systematically neglected. Starting from standard conservation equations, we derive an expression for the acoustic pressure radiated in the far field of a compact region of fluid where low Mach number non-isomolar combustion takes place. In this formulation, the contributions from ‘molar’ and thermal expansion appear explicitly. We also give a formulation in which the sound emission arising from purely non-stationary and from purely convective effects appear independently. As an application of the theory, we derive the acoustic power emitted by a premixed flame in the flamelet regime. Numerical evaluations show that the contribution of molar expansion to the acoustic power is between 2 and 5.6 dB (260% increase) for some common hydrocarbon-oxygen flames.