混合器中燃气/空气掺混特性研究

合理的混合器结构对组合动力系统的高效燃烧和推进性能具有重要意义。为了获得最佳掺混效果,缩短燃烧室长度,利用CFD程序分别对环形、旋流器型和波瓣混合器中内、外涵燃气/空气的流动和掺混特性进行了全三维数值模拟。燃气为甲烷液氧富燃燃气。结果表明：无论采用何种混合器,随着掺混距离的增加,总温和组分均趋均匀;其中,波瓣混合器的掺混效果最好,内外双旋流型混合器的掺混效果次之,环形混合器的掺混效果较差;环形混合器内涵燃气喷射角度对燃气/空气掺混效果具有一定的影响,燃气与轴向成15°喷射时,掺混效果优于无角度喷射。

Numerical Simulation of the Gas/Air Mixing Characteristics in Mixers

The mixer configuration has an important effect on the combustion and propulsive performance of the combined power system.In order to obtain the best mixing performance and reduce the combustor length,the mixer optimization based on numerical simulation is addressed.The flow of gas/air and mixing characteristic inside three different mixers are obtained from three-dimensional CFD simulation.The annular mixer,swirl mixer and lob mixer are designed and used here.The burnt gas from inner flow passage is rich methane/O2（l）burnt gas,while air flows by the by-bass.The simulation results indicate that no matter which mixer is used,the total temperature and species distribution turn to be uniform with the mixing length increasing.The best mixing performance occurrs in the lob mixer,and secondary mixing performance occurrs in the swirl mixer,while the annular mixer is of the worst mixing performance.The injection angle of burnt gas is of considerable effect on the mixing performance.The mixing performance with injection angle of 15 degree is better than that with injection angle of zero.