煤气化数值模拟中湍流气相反应模型的比较研究

Comparison study on three turbulence-chemistry interaction models in numerical simulation of coal gasification

为获得煤气化炉数值模拟研究中常用湍流气相反应模型的适用性和准确性,通过数值模拟分析比较了3种湍流气相反应模型计算的温度场、浓度场和碳转化率分布,并与实验数据进行比较。结果表明:湍流气相反应模型对气化炉火焰区温度场和浓度场计算影响较大,但是对气化炉后部影响较小;EDM模型对合成气组分的浓度分布预测误差较大;基于单混合分数的PDF模型对喷嘴出口附近的温度场和浓度场的预测结果不合理,但是对气化炉出口参数的预测较为准确;EDC模型预测结果良好,但是会高估火焰温度,进一步考虑基元反应和详细化学反应机理可以改善EDC模型对火焰温度的预测。

In order to obtain the applicability and accuracy of commonly used turbulence-chemistry interaction models in the numerical simulation of coal gasification,a numerical simulation was performed using three turbulence-chemistry interaction models,and the temperature field,concentration field and carbon conversion distributions were analyzed and compared with experimental data. The results show that the turbulence-chemistry interaction model has great influence on the temperature and concentration field at the flame zone,while it has little influence on the lower part of the gasifier;the EDM model presents a large prediction error for the concentration distribution of gas compositions; the PDF model based on single mixture fraction gives unreasonable temperature and concentration field near the nozzle outlet,while it gives accurate results at the gasifier outlet;the EDC model gives satisfactory predictions except for overestimating the flame temperature,it is noted that considering elementary reactions and detailed chemical reaction mechanism can further improve the accuracy of predicting the flame temperature.