SiCl_4/H_2/O_2反应动力学及其化学加速计算

SiCl_4/H_2/O_2 Reaction Kinetics and Chemistry Acceleration Calculation

本文提出了一个SiCl_4/H_2/O_2反应动力学模型,并采用H_2/N_2/SiCl_4-N_2/O_2层流对冲扩散火焰实验验证提出的详细机理的准确性,结果表明提出的详细机理获得的结果与测量结果较吻合。该详细机理被应用于熔石英玻璃合成仿真,与四步总包机理相比该详细机理获得了更低且更准确的温度及二氧化硅质量分数。为了在仿真中加快化学计算,本文研究了自适应建表与动态自适应化学的组合化学加速算法TDAC,得出采用TDAC算法能够获得加速因子为2.0的加速效果,且除了SiO_2含量预测有小的偏差外,温度和OH含量预测均较准确。TDAC引起的误差可以通过自适应建表的容差值及DAC的简化阈值进行有效控制。另外,TDAC中初始搜索组分选择对机理简化结果有重要影响,最终产物SiO_2是影响简化结果的关键组分之一,应该被包含在初始搜索组分中。

In this paper,a detailed reaction kinetic model of SiCl4/H2/O2 is first proposed and validated in a laminar H2/N2/SiCl4-N2/O2 counter-flow diffusion flame achieving good agreement with experimental data.Then the reacting flow simulations with this detailed kinetic model have been performed to investigate the fused silica glass synthesis process,in which chemistry calculation is accelerated through the tabulated dynamic adaptive chemistry（TDAC） approach.It is found that compared to the four-step global mechanism,the detailed model yields much lower but more accurate predictions of temperature and SiO2 mass fraction.A speed-up factor of two has been achieved with TDAC for the overall simulations without loss of accuracy in the predictions of temperature and species concentration.The incurred error by TDAC is effectively controlled by the tabulation and reduction thresholds.In addition,it is found that the search-initiating species have significant influence on mechanism reduction in TDAC.The final product SiO2 is the key species and should be included as one of the search-initiating species.