微燃烧器内氢气及甲烷/氢气燃烧的数值模拟

Numerical Simulation of Hydrogen and Methane/Hydrogen Combustion in Micro-burners

为了实现气体在微燃烧器中稳定燃烧的同时还可以获得高且均匀的外壁面温度分布,建立了气体在具有后向台阶微燃烧器中的燃烧模型.首先研究了后向台阶数量对微燃烧的影响,其次研究了不同氢气比例下,甲烷/氢气在具有3个后向台阶微燃烧器中的燃烧特性.结果表明:后向台阶结构能够稳定火焰;当气体的入口速度为3 m/s时,具有3个后向台阶微燃烧器可以燃烧的当量比范围(0.3~5.0)比具有1个后向台阶微燃烧器可以燃烧的当量比范围(0.5~4.6)大;后向台阶结构虽提高了外壁面温度,但使外壁面温差变大,降低了温度的均匀性;在氢气中加入一定比例的甲烷,既减缓了混合气的燃烧反应速度,又获得了高的外壁面温度和能量输出.

In order to achieve stable combustion of gas in micro-burners and obtain high and uniform temperature distribution on the outer wall,a combustion model of gas in micro-burners with backward steps was established.Firstly,the influence of the number of backward steps on micro-combustion was studied.Secondly,the combustion characteristics of methane/hydrogen in micro-burners with three backward steps under different hydrogen ratios were studied.The results show that the backward step structure can stabilize the flame.When the inlet velocity of the gas is 3 m/s,the equivalent ratio range(0.3~5.0)of the gas with three backward steps is larger than that(0.5~4.6)with one backward step.Although the backward step structure increases the temperature of the outer wall,the temperature difference of the outer wall becomes larger,and the temperature uniformity is reduced.Adding a certain proportion of methane to hydrogen not only slows down the combustion reaction rate of the mixture,but also obtains higher outer wall temperature and energy output.