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| 中速磨煤机构件对气相场影响的数值模拟 |
| Numerical simulation on the influence of medium-speed mill components on its gas flow field |
| 投稿时间：2022-03-17 |
| DOI：10.13259/j.cnki.eri.2023.03.005 |
| 中文关键词: 中速磨煤机|数值模拟|模型简化|气相场 |
| 英文关键词:medium-speed mill|numerical simulation|model simplification|gas flow field |
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| 中文摘要: |
| 中速磨煤机内部气相场研究对于燃煤电厂节能减排降碳具有重要意义。然而，中速磨煤机内部构件复杂且存在旋转部件，已有研究往往对磨煤机结构及运行进行简化处理，这势必影响气相场模拟的准确性。采用Realizable k−ε湍流模型，对7种不同结构及运行工况下磨煤机内部气相场开展数值模拟，进行网格无关性验证，并评价磨辊、磨碗与风环、分离器的简化处理对气相场数值模拟结果的影响。结果表明，忽略磨辊对研磨区气相场影响明显，而磨辊转速由28.62 r·min−1变化为57.24 r·min−1时，典型截面气相速度和磨煤机压力损失几乎不变；忽略磨碗与风环的转动，风环上方平均风速将被低估14.97%，磨煤机压力损失将被低估5.02%；忽略分离器部分对研磨区气相场影响很小，而对研磨区上方内锥体区域气相场影响显著，并使得典型截面气相速度误差高达4.80 m·s−1。研究结果可为磨煤机内部流场准确、高效的数值模拟提供方法指导。 |
| 英文摘要: |
| The study on internal gas-phase field of medium-speed coal mill is of great importance for energy saving, emissions reduction, and carbon reduction in the coal-fired power plants. Due to the complex internal components and the presence of rotating parts in the medium-speed coal mill, simplifications on the coal mill structure and operation were often made in the existing studies, which inevitably affected the simulation accuracy of the gas phase field. The Realizable k-ε turbulence model was used to numerically simulate the internal gas phase field of a coal mill under seven different conditions such as structure and operation. The meshing independence verification was performed. Effect of the simplifications of the mill roller, grinding bowl and nozzle ring, and separator on the gas-phase field was evaluated. Results show that ignoring the mill roller has a significant effect on the gas phase field in the grinding zone, and when the rotation speed of mill rollers changes from 28.62 to 57.24 r·min−1, the gas phase velocity at the typical cross-section and pressure loss of coal mill almost remain constant. Ignoring the rotation of grinding bowl and wind ring underestimates the average air velocity and pressure loss of coal mill by 14.97 and 5.02%, respectively. Neglecting the separator part has minor effect on the gas phase field in the grinding area, while significant effect on the gas phase field in the inner cone is observed, which causes a high gas velocity difference of 4.80 m·s−1 at the typical cross-section. The results can provide methodological guidance for accurate and efficient simulation of flow field in the coal mill. |
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