Numerical investigation of unsteady laminar methane / LOx flamelet at supercritical pressures
Numerical investigation of unsteady laminar methane / LOx flamelet at supercritical pressures
复制标题
超临界压力下不稳定层流甲烷/LOx 火焰的数值研究
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
M. Valorani
中科院分区：
文献类型：
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作者：
P. E. Lapenna;P. P. Ciottoli;F. Creta;M. Valorani
高压燃烧装置，例如液体火箭发动机，通常具有跨临界和超临界运行条件。注入燃烧室的推进剂经历极高的密度梯度和真实的流体效应。在本研究中，在非稳态层流小火焰方程的框架中研究了真实流体对火焰结构的影响，这是一种针对非预混燃烧瞬态现象的成熟表示和诊断工具。通过以通用且全面的三参数方式编写的计算高效的三次状态方程来考虑真实流体的热力学性质。选择用于非稳态火焰结构计算和分析的高压条件作为甲烷/液氧火箭发动机工作条件的代表性范围。特别关注低温下的恒压比热行为，它影响火焰结构的时间演化。此外，小火焰方程的时间精确积分代表了超临界湍流燃烧条件矩闭合的第一个构建块。
High-pressure combustion devices, such as liquid rocket engines, are usually characterized by transcritical and supercritical operating conditions. Propellants injected in the combustion chamber experience extremely high density gradients and real fluid effects. In the present study, real fluid effects on flame structure are investigated in the framework of unsteady laminar flamelet equations, a well established representation and diagnostic tool for non premixed combustion transient phenomena. Real fluid thermodynamic properties are taken into account by means of a computationally efficient cubic equation of state written in a general and comprehensive three-parameter fashion. High-pressure conditions for unsteady flame structure calculations and analysis are chosen as a representative range of a methane/liquid-oxygen rocket engine operating conditions. Particular focus is posed on the constant pressure specific heat behavior at low temperature, which influences the time evolution of the flame structure. Moreover time accurate integration of flamelet equations represent the very first building block of a conditional moment closure for supercritical turbulent combustion.