燃煤锅炉气体再燃混合特性的三维数值模拟

Three Dimensional Modeling of Gas Reburning Mixing Process of Coal-fired Boiler

研究全尺寸锅炉内气体再燃的混合特性。通过三维模型,考察煤粉切圆燃烧锅炉内的混合特性。结果表明,再燃燃料的喷入速度,喷口的宽高比对再燃燃料的混合过程有显著的影响,而再燃区的高度对混合过程的影响很小。计算表明,当再燃燃料喷入量保持不变时,采用较大的再燃燃料射入速度、等边的喷口和较大的再燃烧区高度有利于再燃气与烟气的混合。

This paper investigations the mixing characteristics of gas reburning on the full-scale boiler.Mixing process originated by injecting reburning gas in the tangentially coal-fired boiler is examined by a three dimensional numerical model.Attention is focused on the influences of the reburning gas velocity,the ratio between the nozzle width and height,as well as reburning zone heights on the mixing process.It is remarkable that the reburning gas velocity and the ratio between the nozzle width and height has significant influence on the mixing process,and that the influence of reburning zone heights is weak.Predictions indicates that,when keeping the reburning fuel flux constant,greater reburning gas velocity,the equal sides nozzle and the greater reburning zone heights are prefer to obtain well mixed effect.