掺氢比对微波瓣燃烧器燃烧特性的影响

Effects of Hydrogen Blending Ratio on CombustionCharacteristics of Micro-Lobed Burner

关键词:  微波瓣燃烧器  掺氢比  流向涡  燃烧特性  温度分布

Key words:  Micro lobed burner  Hydrogen blending ratio  Streamwise vortices  Combustion characteristics  Temperature distribution

摘要:

为解决微尺度非预混燃烧中燃料同氧化剂混合慢、燃烧不稳定的问题，基于实验的方法研究了燃料掺氢以及微波瓣燃烧器对燃烧的影响，并将微波瓣燃烧器的燃烧温度同微圆管燃烧器进行了对比。在此基础上建立了微波瓣燃烧器以及微圆管燃烧器的三维仿真模型，研究了掺氢比对微波瓣燃烧器和微圆管燃烧器流场、火焰长度、燃料消耗率、燃烧产物以及燃烧温度的影响。研究结果表明：随着掺氢比的增加，微波瓣燃烧器中流向涡涡量以及射流核心速度不断提高，火焰长度、燃烧温度不断增加，OH，H₂O质量分数的峰值逐渐增加，CO₂质量分数的峰值不断下降，CO质量分数峰值变化极小。在同一掺氢比下，相比于微圆管燃烧器，微波瓣燃烧器能够使燃料同氧化剂提前反应且具备更长的火焰、更大的OH质量分数峰值以及更高的燃烧效率和燃烧温度。在掺氢比为50%时，微波瓣燃烧器的最高燃烧温度较微圆管燃烧器提高了110K。这表明微波瓣燃烧器和燃料掺氢的结合能促进微尺度燃烧，提高燃烧的稳定性。

Abstract:

The effects of hydrogen blending and micro lobed burner on the micro non-premixed combustion were studied by experiment to solve the slow mixing between fuel and oxidant and unsteady combustion in the micro combustion. Moreover, the combustion temperatures of micro lobed burner were compared with the ones of micro splitter burner. Based on the experiment, three-dimensional simulation model of micro lobed burner and micro splitter burner was established to research the effects of hydrogen blending ratio on flow field, flame length, fuel consumption ratio, combustion products and temperature in the micro combustion systems. The results show that as the hydrogen blending ratio increases, the streamwise vorticity, jet velocity, flame length and combustion temperature in the micro lobed combustion system increase. Moreover, when the hydrogen blending ratio goes up, the maximum of mass fraction of OH and H₂O in the micro lobed combustion system increase, the maximum of mass fraction of CO₂ gradually falls down, the maximum of mass fraction of CO nearly does not change. In the same hydrogen blending ratio, the micro lobed burner can make the fuel react with the oxygen earlier than the micro splitter burner. Moreover, the micro lobed burner has longer flame, bigger maximum of mass fraction of OH and higher combustion efficiency and temperature than the micro splitter burner. When the hydrogen blending ratio is 50%, the max combustion temperature of micro lobed burner is 110K higher than the one of micro splitter burner. This shows that the combination of micro lobed burner and hydrogen blending can strenghten the micro-scale combustion and improve its stability.