气体取样分析在脉冲燃烧风洞试验中的应用

针对脉冲燃烧风洞试验条件及超燃冲压发动机燃烧室出口流场环境,设计了用于脉冲燃烧风洞流场氧气组分浓度校核及发动机燃烧室出口气流组分分析的探针取样-气相色谱分析测量系统,并在此基础上完成了对取样探针内部流场特性及燃气化学反应冻结情况分析.分析结果表明,进入探针的气流被有效冷却,能够实现化学反应冻结.利用风洞试验气流进行了系统校核,系统控制方面能够满足脉冲风洞试验测量要求,所得到的气流中氧气含量测量值与理论值吻合较好,偏差小于5%,甚至低至0.4%.利用该系统对马赫数2.6来流条件、直连式燃烧室模型燃烧工况下,出口不同位置处燃气中O2、N2和CO2等主要气体组分进行了直接测量,并进而估算了各测点处的表观燃烧效率,获得了其变化情况,所得到的结果在一定程度上反映了燃烧室中燃料的分布情况.

Gas sampling and analysis in pulse combustion wind tunnel tests

The gas composition at the scramj et combustor exit is necessary for the combustion efficiency evaluation.Based on the testing condition of the pulse combustion wind tunnel and the flow field environment at the exit of the scramj et combustor,a gas sampling analysis system was designed and established for the oxygen concentration calibrating in the flow field of the pulse combustion wind tunnel and then for the gas composition measuring at the exit of the scramj et combustor.The flow characteristics and the chemical reaction frozen in the probe during sampling were analyzed.The results indicated that the gas inbreathed by probe could be availably cooled and the chemical reaction could be quenched.The gas composition at the nozzle exit of the pulse combustion wind tunnel was measured for checking the gas sampling analysis system.The control sequence of the gas sampling system could suffice for the pulse combustion wind tunnel testing.The experimental results of the percentage composition of O2 were agreed with the calculation results,and the deviation was less than 5%,even approached to 0.4%.At present,with the working condition of Ma=2.6 and fuel injection,the main components at the exit of the scramjet combustor,such as O2 ,N2 and CO2 were measured directly.The apparent combustion efficiencies for different locations were acquired through the experimental results. The variation of the apparent combustion efficiencies,in a manner,was found to be agreed with the fuel distribution.