氢气/氧气/稀释气混合气高温高压下层流燃烧速度的测量

利用定容燃烧弹和高速纹影摄像系统，研究了高温高压条件下，不同稀释气和稀释系数对氢气/氧气/稀释气混合气层流燃烧速度的影响，获得了当量比为0.6~4.0，初始压力为0.1~0.5MPa，稀释系数为4~8的氢气/氧气/稀释气混合气的层流燃烧速度，并对其进行了数值模拟。实验和模拟均发现，在当量比小于1.0和大于3.0的范围内，层流燃烧速度均随初始压力升高而降低。而在当量比为1.0~3.0范围内，层流燃烧速度随初始压力升高呈现非单调变化的规律。通过敏感性分析发现三体反应（R15）在氮气作为稀释气的时候是抑制反应，而在氩气和氦气作为稀释气时是促进反应，主要是由于各稀释气热物性不同引起的。在当量比为1.0~3.0范围内，层流燃烧速度随初始压力升高呈现的非单调变化主要是链分支反应R1和链终止反应R15相互竞争的结果。 

Measurements on laminar burning velocities of hydrogen/oxygen/diluents at elevated pressure and temperature

The effects of different diluents and dilution ratios on laminar burning velocities of hydrogen/oxygen/diluents mixtures were studied at elevated pressures and temperatures with a constant volume combustion chamber and a high-speed schlieren system.Both experimental and numerical laminar burning velocities of hydrogen/oxygen/diluents mixture were obtained at equivalence ratios of 0.6-4.0,initial pressures of 0.1-0.5 MPa,and dilution ratios of 4-8.The results showed that the laminar burning velocity varied non-monotonically with the increase of the initial pressures and equivalence ratios among 1.0-3.0,and the laminar burning velocity deceased with the increase of initial pressure when the equivalence ratio was less than 1.0 or more than 3.0.Through sensitivity analysis of elemental reaction,three-body reaction (R15) was found to restrain reaction in nitrogen diluted mixture,and promote reaction in both argon and helium diluted mixtures,mainly due to different thermal physics properties of different diluents.When the equivalence ratios were within the ranges of 1.0-3.0,the non-monotonic change of laminar burning velocities with the increase of initial pressures was mainly due to the competition between chain branching reaction R1 and chain-terminating reaction R15.