高温空气燃烧炉内湍流混合特性的数值研究

Numerical Investigation of Turbulent Mixing in a High Temperature Air Combustion Furnace

应用自行研发的三维流动、燃烧、传热和污染物NOx湍流生成的数值模拟程序,对高温空气燃烧实验模型炉进行了湍流扩散燃烧混合特性的数值模拟.数值预报了燃烧室内气体燃料和空气的混合物分数及其湍流脉动的三维分布.数值研究结果表明:在一定的几何条件和气体动力学条件下,高温空气燃烧的湍流混合在更广泛的区域内以较小梯度的进行;混合物分数的脉动主要分布在燃烧区,这表明高温空气燃烧的火焰厚度更大,具有燃烧释热更趋均匀的特性.数值模拟结果与相关的实验结果有相同的规律.

A three-dimensional numerical simulation of the non-premixed combustion turbulent mixing processing in high temperature combustion furnace has been performed with authors developed computer program of flow, combustion, heat transfer and NOx turbulent formation. The 3d-distributions of mixture fraction and its turbulent fluctuation are forecasted under three different inlet air temperature conditions in combustion furnace. Compared with non-premixed combustion, the results demonstrate that, under certain geometry and dynamical conditions, the turbulent mixing of high temperature air combustion proceeds with smaller intensity within a larger zone; the turbulent mixture fluctuation distributes within the larger combustion zone. This also indicates that the flame thickness appears to be larger and that heat is released within larger combustion zone. The simulating conclusions are in agreement with the results of similar experiments.