辛烷和空气逆向流扩散火焰的数值模拟

以多孔壁注入燃料流与逆向空气射流所构成的有燃烧的层流边界层流动为研究对象,建立了一组描述在边界层中有气相反应的偏微分方程组.该方程组经相似变换和线性化,然后采用带系数的牛顿迭代法求解.首先对甲烷和空气逆向流扩散火焰结构进行了算例分析与结果验证,然后对目前尚属首例的辛烷和空气逆向流扩散火焰进行了预测分析,其中燃烧反应计算涉及51种化学组分、369步基元反应.

A Numerical Study on Octane-Air Counterflow Diffusion Flame

This paper deals with laminar reactive boundary layer flows in which hydrocarbon fuel is blown from a porous cylinder into an on-coming air stream. The partial differential equations of conservation of mass, momentum, energy and chemical constitutents are given to describe the flow problem under consideration. A similarity solution is briefly outlined so that the governing boundary layer equations are transformed into one-dimensional form in space, and the resulting linear equations are solved numerically by Newton' s iteration method. The model is used first to predict the structure of counterflow methane-air diffusion flames. It is shown by comparing the predicted results with the current experimental data that the temperature , velocity and species mole fraction profiles can be predicted fairly accurately. The model has also been applied in the numerical study of the structure of counterflow octane-air diffusion flames. In the calculation of the combustion reaction 369 elementary steps and 51 chemical constituents are involved.