对流扩散化学反应动力学方程的流动坐标解法

Solution under convective coordinate for convection-diffusion chemical reaction kinetic equations

对于两种介质并行流动的对流扩散化学反应问题 ,给出了在流动坐标系下的化学反应动力学方程的解法 .在这个坐标系下 ,对流项消失了 ,只是一个化学反应、扩散方程 ,即在每个时间步的计算只有反应扩散而没有流动 .流体的流动体现在计算域随时间步的增加而增加 ;并且 ,流体流进计算域的时间就是其化学反应和扩散的时间 ,因此流体各个质点的反应、扩散时间是不同的 .本算法克服了因流体介质前端物理量分布的间断引起的计算上的数值虚假摆动 ,进而避免了对化学反应计算的不利影响 .算例表明 ,该算法是有效的 .

Chemical reaction takes place when two chemical liquids flow parallelly and diffuse into each other. A solution for chemical reaction kinetics under the convective coordinate was presented to solve convection-diffusion chemical reaction equations. Under this coordinate, these equations became reaction-diffusion equations without convection terms, viz. only reaction and diffusion terms was calculated in each time step. The flux of the liquids was shown in the increase of calculation region as time step increased; and the time to react and diffuse of each particle was equal to the time after they flow into the calculation region, so the time to react and diffuse for every particle in the liquids differed from each other. This method avoided the spurious numerical oscillations in calculation caused by the flow discontinuity in front of the materials, which showed serious unstable influence on solution. Numerical examples demonstrated that this algorithm was effective.