气氢气氧同轴剪切喷注器燃烧流场的PLIF测量及仿真研究

Simulation and PLIF Experiment Study of Combustion

关键词:  同轴剪切喷注器  气-气燃烧  平面激光诱导荧光  数值仿真

Key words:  Shear coaxial injector  Gas-gas combustion  PLIF  Numerical simulation

摘要:

为探究同轴剪切气气喷注燃烧火焰结构及验证仿真方法的可行性，利用RANS方法对实验工况进行了计算，得到了燃烧室温度和OH分布，以及流场结构。并通过实验，利用平面激光诱导荧光(PLIF)技术测量了透明燃烧室内气氢气氧同轴剪切喷注燃烧火焰的激光诱导OH荧光，得到了火焰结构图像。实验结果表明，在燃烧室前端形成了回流区和结构稳定的剪切燃烧层，在剪切和回流的共同作用下形成了OH尖峰。随OH尖峰下游湍流涡的发展，火焰结构产生褶皱，使燃烧得到了加强。将仿真和实验结果进行对比发现，两者剪切燃烧层位置最大相差0.6mm，OH尖峰轴向位置相差2mm，径向尺寸均为7mm。仿真和实验结果吻合较好，利用该仿真模型对实际情况进行预测是可行的。

Abstract:

In order to study the flame structure of gas-gas combustion and the practicability of the simulation method，RANS was applied to get the temperature，OH distribution and the characteristics of flow field. In addition，planar laser induced hydroxyl fluorescence (OH-PLIF) technology has been used to image the flame utilizing gas hydrogen/gas oxygen shear coaxial injector in a transparent combustion chamber. The results show that a large recirculation zone and a stable combustion shear layer are established in the front of the chamber. The shear stress，together with the influence of recirculation，shapes a OH peak，and its size and position were measured. With the development of turbulent vortex，folds occur and the combustion are enhanced. The comparison of the results of experiment and simulation shows that there are deviations of 0.6mm in the position of combustion shear layer and 2 mm in the axial position of OH peak. While the radial positions of OH peak are both 7 mm. The simulation results are in good accordance with the measurements although they moderately overpredict the positions of combustion shear layer and OH peak. It is concluded that the computational model can be used to predict the experiment conditions.