生物质发电锅炉炉内冷态流场的数值模拟与火花示踪测试

Numerical Simulation and Spark Tracer Measurement of Cold-state Flow Field in a Biomass-fired Power Boiler

针对某电厂2号机组改造后由原设计燃料淮南大通烟煤改烧生物质燃料的现状,首先采用Fluent软件模拟了抛煤口改为一次风口并加大二次风量后的炉内流场;其次,对前后二次风射流角度进行了调整,模拟了二次风角度调整后的炉内流场;在确定二次风射流角度后,又模拟了不同风量配比条件下的炉内流场,对比分析得到最佳风量配比条件;在配风系统改造方案实施后,对新配风系统的炉内冷态流场进行了火花示踪试验和研究.结果表明:机组经改造后,炉内的流场比较合理,一次风无明显偏斜,二次风切入一次风主流的位置合理,为机组的热态调试和运行提供了参考依据.

In order to change the fuel for the No.2 power generation unit in a certain power plant from the original Huainan Datong bituminous coal into biomass fuel,numerical simulations were repeatedly carried out to its in-furnace flow field using Fluent software respectively under following assumptions： first,taking the spreader stoker tuyere as the primary air port,and raising the secondary air flow rate;second,adjusting the angle of secondary air jet;third,with a determined angle of secondary air jet,changing the distribution ratio of primary and secondary air,thus obtaining an optimum ratio on the basis of comparison and analysis.The in-furnace cold-state flow field was visualized by using spark tracing technique on the assumption that the retrofit scheme has been implemented to the air distribution system.Results show that after retrofit,the in-furnace flow field will become more reasonable,the angle of primary air jet will have not obvious deviation,the cut-in position of secondary air into mainstream of primary air will be appropriate.All these may serve as a reference for hot-state commissioning and operation of the unit.