双锥燃烧器外侧风道传热分析

为解决煤粉工业锅炉燃烧器风冷外壁过热问题,通过数值模拟对双锥燃烧器外侧风道传热进行了分析。模拟结果与实际相符,燃烧器风冷前锥外壁存在条带状高温区,且最高温点位于二次风入口对侧。由于外壁面的切向热传导,实际温度分布比模拟结果均匀,但两者规律一致。在50%~100%负荷内,随着燃烧器负荷降低,由于煤粉在燃烧器中停留时间增长,燃烧进程增加,外壳温度呈显著上升趋势。分析了加入回流挡板、增设隔热层2种结构优化对燃烧器外侧风道传热的影响。2种方式均可有效缓解燃烧器外壁过热问题,但加入回流挡板增加了二次风阻力,增设隔热层会使风冷前锥温度上升。 In order to solve the overheating problem of external wall which was installed in burner of pulverized coal industrial boiler,the heat transfer of outside air duct was analyzed by numerical simulation. The simulation results reflected the actual situation accurately,the outer wall of front cone was in a strip temperature zone,and the maximum temperature point was located at the opposite side of inlet. The actual temperature distribution was more uniform than the simulation results due to the tangential heat conduction of outer wall surface. At the rated load scope of 50% to 100%,with the decrease of burner load,the shell temperature increased significantly. This was because long residence time led to long combustion process. The add of reflux baffle and insulation layer could effectively control the heat accumulation problem,while the reflux baffle increased secondary air resistance,the insulation layer increased the temperature of air cooling front cone rised