To know how equivalence ratio effect on flame characteristic of NexGen burner,a computational fluid dynamic of NexGen burner is established.The computational fluid dynamics are performed with ANSYS Fluent.The combustion model is Non-Premixed Combustion with 20-species probability density function method for the reaction of single kerosene species C12H23.The Reynolds-averaged Naiver-Stokes with SST k-ω turbulence model for resolving the turbulent behavior of flame.The discrete ordinates radiation model is used and the gas emissivity using the weighted sum of gray gasses model.Liquid fuel droplets interact with the turbulent gas medium in accordance with the discrete random walk model.The effects of seven groups of equivalent ratios on the point distribution,plane distribution and spatial distribution of fire temperature were analyzed.Get increased with the increase of equivalence ratio,the highest temperature along Z axis increases first and then decreases;the average temperature of monitoring points increased first and then decreased;the maximum temperature of monitoring plane decreased first and then changed slowly increased again,similar to the bathtub curve;the average temperature monitoring plane decreased first and then increased again.When the equivalent ratio is less than 1,the average temperature of planes decreases with the increase of the equivalent ratio,while increases when the equivalent ratio is more than 1.When the equivalent ratio is 0.9,the spatial temperature distribution of flame is the best,the temperature distribution of planes is the most uniform,the temperature distribution of the monitoring plane is the most uniform,and the temperature and distribution of the seven monitoring points are moderate.%为得到当量比对航空发动机防火试验温度分布的影响,建立了NexGen燃烧器的数值计算模型,使用Fluent计算了7组当量比的火焰温度分布.燃烧模型采用非预混燃烧模型与20组分单煤油分子C12H23的概率密度函数方法.使用雷诺时均模型与SST k-ω湍流模型求解火焰的湍流方程.使用离散坐标辐射模型和灰体加权平均模型的求解火焰的辐射.液体燃料液滴根据离散随机游走模型与湍流气体介质的相互作用建立模型.分析了7组当量比对防火试验火焰温度的点分布、面分布和空间分布的影响.得到随当量比的增加,Z轴最高温度位置先变大后减小;监测点的平均温度先升高后降低;监测面的最高温度先降低后变化平缓再增加,与浴盆曲线相近;监测面的平均温度先降低后平缓再增加.当量比小于1时,各平面的平均温度随当量比增加而降低;当量比大于1时则升高.当量比为0.9时,火焰空间温度分布最好、各平面的温度分布最均匀、监测面的温度分布最均匀、七个监测点的温度值及分布适中.
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