甲烷-液氧超临界压力非预混湍流燃烧的数值模拟  

Numerical simulation of CH_4-LO_x non-premixed turbulent combustion at supercritical pressures

作　　者：汪秋笑 黄东欣 孟华[1] 

机构地区：[1]浙江大学航空航天学院,杭州310027

出　　处：《航空学报》2016年第7期2132-2143,共12页Acta Aeronautica et Astronautica Sinica

基　　金：国家自然科学基金(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，开展了甲烷一液氧（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（6～15MPa）对甲烷一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6MPa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。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 turbulentcombustion treatment, and it accommodates accurate calculations of thermophysical properties and a detailed chemicalreaction mechanism. It is applied to conduct numerical studies of the coaxial injection and non-premixed turbulent combustionof CH_4-LO_x at supercritical pressures. The effects of supercritical pressures （6 to 15 MPa） on the combustion processes areexamined at different propellant mixture ratios （ 1 and 3）. Results reveal that the effects of pressure on the flame temperatureand structure change remarkably at different mixture ratios. At a propellant mixture ratio of 1, the flame length and flametemperature both increase as pressure increases, while at a mixture ratio of 3, the flame length decreases as pressureincreases. At a supercritical pressure, the turbulent flame exhibits a sudden expansion in the radial direction （particularly at6 MPa）, because of pseudo boiling resulting from the LO_x property anomaly at the pseudo-critical temperature. Thisphenomenon can also be influenced by the LO_x injection momentum.

关 键 词：非预混火焰 湍流燃烧 超临界压力 火焰面一反应进度变量 混合比 

分 类 号：V511[航空宇航科学与技术—航空宇航推进理论与工程]