This paper presented a coupled heat transfer model combining the combustion in the furnace and the ultra-supercritical(USC) heat transfer in the water wall tubes. The thermal analysis of the spiral water wall in a 100...This paper presented a coupled heat transfer model combining the combustion in the furnace and the ultra-supercritical(USC) heat transfer in the water wall tubes. The thermal analysis of the spiral water wall in a 1000 MW double reheat USC boiler was conducted by the coupled heat transfer simulations. The simulation results show that there are two peak heat flux regions on each wall of spiral water wall, where the primary combustion zone and burnt-out zone locate respectively. In the full load condition, the maximal heat flux of the primary combustion zone is close to 500 kW/m^2, which is higher than that in the conventional single reheat USC boilers. The heat flux along the furnace width presents a parabolic shape that the values in the furnace center are much higher than that in the corner regions. The distribution of water wall temperature has a perfect accordance with the heat flux distribution of the parabolic shape curves, which can illustrate the distribution of water wall temperature is mainly determined by heat flux on the water wall. The maximal water wall temperature occurs at the middle width of furnace wall and approaches 530°C, which can be allowed by the metal material of water wall tube 12Cr1MoVG. In the primary combustion zone, the wall temperatures in half load are almost close to the values in 75% load condition, caused by the heat transfer deterioration of the subcritical pressure fluid under the high heat flux condition. The simulation results in this study are beneficial to the better design and operational optimization for the double reheat USC boilers.展开更多
采用双线性四边形法对螺旋管圈水冷壁和鳍片进行了剖分。将螺旋管圈水冷壁在平面上展开并划分为7个区段,采用分区段热力计算的方法确定各区段平均热负荷,通过对焓增值的计算确定各管工质在各个区段入口和出口的压力和温度。在螺旋管圈...采用双线性四边形法对螺旋管圈水冷壁和鳍片进行了剖分。将螺旋管圈水冷壁在平面上展开并划分为7个区段,采用分区段热力计算的方法确定各区段平均热负荷,通过对焓增值的计算确定各管工质在各个区段入口和出口的压力和温度。在螺旋管圈出口位置布置了温度测点,计算了在70%锅炉最大连续蒸发量(boiler maximum continuous rating,BMCR)、65%BMCR、60%BMCR3种工况下的各段校核水冷壁壁面温度,通过螺旋管圈出口处计算值与测量值的比较验证了计算模型的合理性。采用传热恶化试验关联式,预测了超临界锅炉运行在近临界压力区发生传热恶化后的最高管壁温度,为锅炉的安全运行提供了比较可靠的参考数据。展开更多
基金the financial support of the National Key Research & Development Program of China (Grant No.:2017YFB0602102)
文摘This paper presented a coupled heat transfer model combining the combustion in the furnace and the ultra-supercritical(USC) heat transfer in the water wall tubes. The thermal analysis of the spiral water wall in a 1000 MW double reheat USC boiler was conducted by the coupled heat transfer simulations. The simulation results show that there are two peak heat flux regions on each wall of spiral water wall, where the primary combustion zone and burnt-out zone locate respectively. In the full load condition, the maximal heat flux of the primary combustion zone is close to 500 kW/m^2, which is higher than that in the conventional single reheat USC boilers. The heat flux along the furnace width presents a parabolic shape that the values in the furnace center are much higher than that in the corner regions. The distribution of water wall temperature has a perfect accordance with the heat flux distribution of the parabolic shape curves, which can illustrate the distribution of water wall temperature is mainly determined by heat flux on the water wall. The maximal water wall temperature occurs at the middle width of furnace wall and approaches 530°C, which can be allowed by the metal material of water wall tube 12Cr1MoVG. In the primary combustion zone, the wall temperatures in half load are almost close to the values in 75% load condition, caused by the heat transfer deterioration of the subcritical pressure fluid under the high heat flux condition. The simulation results in this study are beneficial to the better design and operational optimization for the double reheat USC boilers.
文摘采用双线性四边形法对螺旋管圈水冷壁和鳍片进行了剖分。将螺旋管圈水冷壁在平面上展开并划分为7个区段,采用分区段热力计算的方法确定各区段平均热负荷,通过对焓增值的计算确定各管工质在各个区段入口和出口的压力和温度。在螺旋管圈出口位置布置了温度测点,计算了在70%锅炉最大连续蒸发量(boiler maximum continuous rating,BMCR)、65%BMCR、60%BMCR3种工况下的各段校核水冷壁壁面温度,通过螺旋管圈出口处计算值与测量值的比较验证了计算模型的合理性。采用传热恶化试验关联式,预测了超临界锅炉运行在近临界压力区发生传热恶化后的最高管壁温度,为锅炉的安全运行提供了比较可靠的参考数据。
