壁温对氢燃料超燃燃烧室流动特性的影响研究

Effects of Wall Temperature on Flow Characteristics of Hydrogen Fuel Scramjet Combustor

关键词:  超燃冲压发动机  氢燃料  壁面温度  壁面压力  流场结构

Key words:  Scramjet  Hydrogen fuel  Wall temperature  Wall pressure  Flow field structure

摘要:

为了研究超燃燃烧室壁面换热与超声速燃烧之间的关系，运用FLUENT软件，采用RNG k-ε湍流模型、有限速率/涡耗散燃烧模型、密度基AUSM+隐式算法对中国空气动力研究与发展中心的双模态燃烧室模型开展三维冷态和热态流场计算，模拟条件来流马赫数为2.05，总温T_t为1870.9K，分别模拟了壁面温度为500K，700K，900K，1300K以及绝热条件下的超燃燃烧室的燃烧场。燃烧室壁面压力数值模拟结果与实验结果吻合较好，壁面温度为500K，700K，900K，1300K和绝热时，平均误差分别为8.89%，5.78%，14.41%，13.97%，16.53%。通过对比分析发现：随着壁面温度的降低，壁面压力趋势大致不变，但壁面压力值降低，同时壁面压力的压升起始点大幅后移；燃烧所产生的激波串逐渐向燃烧室下游移动，激波串结构发生改变，但激波串前端均为X形激波；燃烧室内马赫数有所升高；燃烧场高温区域面积减小；燃烧室燃烧模态由亚燃模态逐渐向超燃模态转换。

Abstract:

In order to study the relationship between wall heat transfer and supersonic combustion in the scramjet combustor, using FLUENT software with RNG k-ε turbulence model, finite rate/eddy dissipation combustion model, density-based AUSM+implicit algorithm for the dual-mode combustion chamber model of China Aerodynamics Research and Development Center, the three-dimensional cold and hot flow fields are calculated. The simulated incoming Mach number is 2.05, the total temperature is 1870.9K. The flow fields and combustion fields of the scramjet combustor with wall temperatures of 500K, 700K, 900K, and 1300K, respectively, and adiabatic conditions were simulated. The numerical simulation results of the wall pressure of the combustor agree well with the experimental results. When the wall temperature is 500K, 700K, 900K, 1300K and adiabatic, respectively, the average errors are 8.89%, 5.78%, 14.41%, 13.97% and 16.53%. When the wall temperature is 700K, the numerical simulation results are the closest to the experimental results. Through the comparative analysis, it is found that with the decrease of the wall surface temperature, the wall pressure trend is almost unchanged, but the wall pressure decreases, and the starting point of the pressure rise of the wall pressure is greatly shifted back. The shock train generated by the combustion gradually moves downstream of the combustion chamber, and the shock train structure changes, but the front end of the shock train is X-shaped shock wave. The Mach number in the combustion chamber increases, while the area of the high temperature region of the combustion field decreases, then the combustion mode inside the combustor gradually shifts from the sub-combustion mode to the super-combustion mode.