O2／CO2燃烧方式下锅炉对流传热系数的修正算法和数值研究

Modified Algorithm and Numerical Study of Boiler Convective Heat Transfer Coefficient Under O_2/CO_2 Combustion Mode

采用热力计算与数值模拟相结合的方法,对富氧燃烧方式下锅炉对流受热面的传热特性进行研究,获得了富氧气氛受热面对流传热系数的变化规律,由此提出了对流传热系数的修正算法.采用该算法,以某电厂300 MW锅炉为例,分别对空气燃烧方式和O2/CO2燃烧方式下的各受热面进行了热力计算,并将计算结果与模拟结果进行了对比分析,结果两者相吻合,表明修正算法是可行的.分析结果还表明:富氧气氛下烟气的传热能力增强,即相同的受热面积传热量增加.

Heat transfer characteristics of boiler convective heat-absorbing surface under oxygen-enriched combustion mode were studied by a combined method of thermal calculation and numerical simulation. The variation pattern of convective heat transfer coefficient of the heat-absorbing surface in oxygen-enriched atmosphere was obtained. Thus the modified algorithm for convective heat transfer coefficient was proposed. The algorithm was used for the thermal calculation of each heat-absorbing surface of a 300 MW boiler in certain power plant under air combustion mode and O2/CO2 combustion mode separately. Through comparison and analysis, it is found that the calculated results agree well with the simulated results, which indicates that the algorithm is feasible. The analyzed results also show that the heat transfer ability of the flue gas increases under oxygen-enriched atmosphere, namely the amount of heat transfer increases for the same heating surface area.