非预混湍流射流H2/N2扩散火焰中的局部熄火和再燃现象

为了提高燃烧室中燃料的利用率,避免火焰的全局熄火,对于熄火和再燃现象的研究是十分必要的.利用一维湍流(ODT)模型研究了非预混湍流射流火焰中的熄火和再燃现象.在固定雷诺数为10 000的情况下,对两个不同的火焰进行了模拟,这两个火焰具有不同的全局混合速率.熄火现象主要发生在近场区域.随着全局混合速率的增加,局部熄火的区域也随之增加.两个火焰的最大熄火区域分别为20%和62%.在熄火区域,主要污染物NO迅速减少.模拟结果显示熄火是一个快速的过程,而与之相对应的再燃过程则较为缓慢.

Local Extinction and Reignition in Non-Premixed Turbulent Jet H2/N2 Diffusion Flames

In order to maximize efficiency,minimize unburned fuel emissions,and prevent the global extinction of flame,it is necessary to examine and clarify the process of extinction and reignition in practical combustors.This paper studies localized extinction and reignition in nonpremixed combustion in a turbulent context.This is done by modeling the combustion process using the one-dimensional turbulence(ODT) model.Two flames with different global mixing rates at a fixed Reynolds number of 10 000 are simulated.The results show that extinction mainly occurs in the near-field.The increasing of local extinction with increasing global mixing rate is accurately represented by the calculations.The maximum fractions of extinguished stoichiometric region are 20% and 62%,respectively for the two mixing rates.Nitric oxide(NO) is measured and the results show that NO decreases rapidly in the extinguished regions.The simulation result show that extinction is a rapid process while the reignition of the extinguished mixture is slow.