煤粉浓缩器内气固两相流动特性的数值模拟

NUMERICAL SIMULATION OF GAS- PARTICLE TWO PHASE FLOW IN A PULVERIZED-COAL CONCENTRATOR

利用气固两相计算模型(IPSA模型),对水平浓淡煤粉燃烧器关键部件——百叶窗煤粉浓缩器内部压力、速度、浓度场进行了数值模拟,得出了浓缩器内气固两相流动规律,进一步分析了浓缩器的煤粉浓缩机理。计算结果表明,在浓缩器叶片上部出现高煤粉浓度的带状结构,并且在浓侧出口中心位置的煤粉浓缩带内,形成局部的煤粉高浓度区域,这是百叶窗式煤粉浓缩器的主要特点,与试验研究中观察到的气固两相流动现象一致。同时在不同分流挡板开度k下对煤粉浓缩器内部流动进行了数值模拟,得到了浓缩器性能参数,给出其变化趋势,与试验结果对比吻合较好。

A gas-particle two-phase model (IPSA model) is used to simulate gas-particle flows in a louver pulverized-coal concentrator, which is the key element of Horizontal bias combustion burners. The distribution of gas static pressure, gas-particle velocity and pulverized-coal concentration in the concentrator are simulated and presented. The gas-particle flow pattern in this equipment is given and the concentrating mechanism is analyzed. From the simulation, a belt-shape zone with high particle concentration is found near and over the louver blades, and a local high particle concentration zone connected with the belt is found at the center of the concentrator's fuel-rich exit, which is the major characteristic of the louver concentrator and coincides with the phenomena observed in experiments. Other parameters are also calculated at different position of the concentrator distribution baffle, which generally agree with the experiment data. The trend of these parameters is correctly simulated.