氢燃料微混喷射角度对掺混与燃烧特性的影响研究

This paper focuses on the micro diffusion combustion structure of hydrogen，and analyses the effects of hydrogen injector angles on hydrogen-air mixing characteristics，NO_x emissions，and other combustion performance through experiments and numerical methods. The experiments were conducted using a unit burner testing system. The research results indicate that the NO_x emissions of micro diffusion combustion structure of hydrogen show an exponential growth trend，with the most significant increase when the equivalence ratio Φ>0.7. Increasing the injector angle has the effect of suppressing NO_x emissions. The 60° injector reduces NO_x emissions by up to 43.3% compared to the basic scheme，which is related to the reduction in the volume of the high-temperature region inside the micromix burner and mainly affects the temperature between 1 800~1 900 K. Under the test conditions，the 60° injector performs better in terms of noise level and combustion stability. The increase in injector angle affects the velocity distribution inside the burner，enlarges the flow separation zone inside the burner，and thus affects the distribution of mass fraction of OH*，improving the uniformity of temperature distribution. Cold flow field analysis shows that increasing the injector angle increases the length of the hydrogen jet trajectory，resulting in lower levels of spatial mixing inhomogeneity in the main combustion zone and downstream space. The trend of Schmidt number Sc variation indicates that hydrogen air mixing is dominated by mass diffusion，and the ability of hydrogen air mixing is related to the rise and fall of mass diffusion and momentum diffusion. The equivalence ratio distribution further elucidates the reasons for the variation of temperature distribution and NO_x emission. The study revealed the influence of injector angle changes on mixing and NO_x emissions.