侧煤仓布置条件下锅炉热一次风道数值模拟与优化研究

Numerical simulation and optimization of primary hot air duct under side bunker arrangement

以某侧煤仓布置的1 000 MW机组为例,对锅炉热一次风道进行了数值模拟。针对系统总阻力较大、各支管流量分配不均匀的问题,对热一次风母管进行了优化,母管管径随热一次风流量降低而减小;对各支管从母管上的引出方式进行了优化,各支管与母管采用不同角度的弯头连接,可有效降低热一次风系统阻力,使各支管流量趋于均匀。优化后的方案四系统总阻力比方案二降低了19.7%,各支管流量的方差比方案二降低了89.8%。最后对优化后的热一次风系统进行了变工况运行模拟,结果表明,在各种负荷工况下,优化后的热一次风道各支管的流量都较均匀。

Taking a 1 000 MW unit with a side coal bunker as an example, a numerical simulation of the boiler hot primary air duct was carried out. In view of the large total resistance of the system and the uneven flow distribution of each branch pipe, the hot primary air main pipe was optimized. The diameter of the main pipe decreased with the decrease of the hot primary air flow;the way each branch pipe was drawn from the main pipe after optimization, each branch pipe and the main pipe are connected by elbows with different angles, which can effectively reduce the resistance of the hot primary air system and make the flow of each branch pipe tend to be uniform. The total resistance of the optimized scheme four is reduced by 19.7% compared with scheme two, and the variance of the flow of each branch pipe is reduced by 89.8%compared with scheme two. Finally, the optimized hot primary air system is simulated under variable conditions. The results show that the flow of each branch pipe of the optimized hot primary air duct is relatively uniform under various load conditions.