航空学报 > 2016, Vol. 37 Issue (7): 2132-2143   doi: 10.7527/S1000-6893.2015.0279

甲烷-液氧超临界压力非预混湍流燃烧的数值模拟

汪秋笑, 黄东欣, 孟华   

  1. 浙江大学 航空航天学院, 杭州 310027
  • 收稿日期:2015-07-08 修回日期:2015-10-15 出版日期:2016-07-15 发布日期:2015-10-30
  • 通讯作者: 孟华 男,博士,教授,博士生导师。主要研究方向:推进与动力技术。Tel:0571-87952990,E-mail:menghua@zju.edu.cn;Tel.:0571-87952990,E-mail:menghua@zju.edu.cn E-mail:menghua@zju.edu.cn
  • 作者简介:汪秋笑 男,硕士研究生。主要研究方向:超临界压力燃烧,E-mail:1176273589@qq.com;黄东欣 男,硕士研究生。主要研究方向:超临界压力燃烧,E-mail:hdx0411@163.com;
  • 基金资助:

    国家自然科学基金(11372277)

Numerical simulation of CH4-LO<i>x non-premixed turbulent combustion at supercritical pressures

WANG Qiuxiao, HUANG Dongxin, MENG Hua   

  1. School of Aeronautics and Astronautics, Zhejiang University, Hangzhou 310027, China
  • Received:2015-07-08 Revised:2015-10-15 Online:2016-07-15 Published:2015-10-30
  • Supported by:

    National Natural Science Foundation of China (11372277)

摘要:

基于雷诺平均Navier-Stokes(RANS)方法和火焰面-反应进度变量湍流燃烧模型,在准确考虑热物性变化和详细化学反应机理的基础上,建立了适用于超临界压力非预混湍流燃烧的数值模型,开展了甲烷-液氧(LOx)超临界压力同轴喷射非预混湍流燃烧过程的数值模拟研究,着重探讨了推进剂混合比分别为1和3情况下超临界工作压力(6~15 MPa)对甲烷-液氧非预混湍流燃烧过程的影响。 结果表明:不同混合比情况下压力对火焰温度和结构的影响会有显著的不同。在推进剂混合比为1时,随着压力的升高,火焰变得更长,且火焰温度升高;而在推进剂混合比为3时,随着压力的升高,火焰长度则会变短。在超临界压力下,火焰沿径向有突然的扩张现象(特别是在6 MPa压力下)。这主要与液氧物性在拟临界温度附近的突变所造成的拟沸腾现象有关,也会受到液氧喷射动量变化的影响。

关键词: 非预混火焰, 湍流燃烧, 超临界压力, 火焰面-反应进度变量, 混合比

Abstract:

A numerical model has been developed for studying non-premixed turbulent combustion at supercritical pressures. The model is based on the Reynolds-averaged Navier Stokes (RANS) equations and the flamelet-progress variable turbulent combustion treatment, and it accommodates accurate calculations of thermophysical properties and a detailed chemical reaction mechanism. It is applied to conduct numerical studies of the coaxial injection and non-premixed turbulent combustion of CH4-LOx at supercritical pressures. The effects of supercritical pressures (6 to 15 MPa) on the combustion processes are examined at different propellant mixture ratios (1 and 3). Results reveal that the effects of pressure on the flame temperature and structure change remarkably at different mixture ratios. At a propellant mixture ratio of 1, the flame length and flame temperature both increase as pressure increases, while at a mixture ratio of 3, the flame length decreases as pressure increases. At a supercritical pressure, the turbulent flame exhibits a sudden expansion in the radial direction (particularly at 6 MPa), because of pseudo boiling resulting from the LOx property anomaly at the pseudo-critical temperature. This phenomenon can also be influenced by the LOx injection momentum.

Key words: non-premixed flame, turbulent combustion, supercritical pressure, flamelet-progress variable, mixture ratio

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