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为了准确地数值预报煤粉旋流火焰特征和主要烟气成分,比较扩展的涡耗散模型在多湍流模型下的预测性和影响,针对IFRF(国际火焰研究基地)2.5MW煤粉氧燃烧和空气燃烧实验,利用组分输运方程,结合7步改进的总包反应,对炉内煤粉氧燃烧进行数值计算,并与实验结果和空气燃烧基况对比.结果表明:氧扩散率、发射率和比热容等物性参数修正后,湿循环、氧预混二次流的煤粉氧燃烧扩散火焰温度场与空气燃烧总体一致,火焰稳定且为Ⅱ型火焰结构;EDC模型(涡耗散概念模型)对组分预测更为准确,尤在可实现k-ε模型下的缓慢反应CO生成和IRZ(中心内回流区)高温预测;而FRED模型(有限速率涡耗散模型)在多湍流模型下对炉内温度、组分、火焰结构预测亦较准确.
In order to accurately predict the characteristics of pulverized coal swirl flame and main flue gas composition, the predictability and impact of extended vorticity dissipation model under multi-turbulence model are compared. According to IFRF (International Flame Research Base) 2.5MW pulverized coal combustion and Air combustion experiments were carried out to calculate the oxygen combustion in the furnace by using the component transport equation combined with the seven-step improvement of the total reaction.The experimental results and air-combustion conditions were compared.The results show that the oxygen diffusion rate, the emission After the correction of physical parameters such as temperature, specific heat rate and specific heat capacity, the flame temperature field of coal-fired oxy-fuel combustion diffusion flame is consistent with that of air combustion in wet cycle and oxygen premixed secondary flow, and the flame is stable and of type Ⅱ flame. EDC model ) Is more accurate for predicting the composition, especially for the slow response CO generation in k-ε model and the high temperature prediction in IRZ (central backflow zone), while the FRED model (finite rate vortex dissipation model) On the furnace temperature, composition, flame structure prediction is also more accurate.