环缝可调风帽型流化床CFD数值模拟与验证实验-化工过程机械专业论文.docxVIP

华中科技大学硕士学位论文 华 中 科 技 大 学 硕 士 学 位 论 文 I I 摘要 本研究应用计算流体动力学软件 Fluent 6.3.26 的欧拉双流体模型，对带有 43 个环 缝型风帽的气固流化床反应器的流化状态进行了二维及三维数值模拟。其中固相为粒 径 87.4μm，真密度 3550kg/m3 的 B 型氧化铝颗粒，气相为常温 25℃下空气，密度为 1.185 kg/m3，动力粘度为 1.835×10-5 Pa·S。在实施模拟之前，为了方便检验数值模 拟方案的可行性，先对静止料层高 30mm，流量 30m3/h 的流化床反应器进行了验证 性实验。数值模拟的物理模型完全由该验证实验中的实验模型简化而来。在二维数值 模拟中重点研究了 4 种曳力模型及两种湍流模型对数值模拟流化状态的影响，最终结 果表明，修正后的 syamlal-obrien 曳力模型所模拟的流化状态和实际情况较为相符， 模拟与实验两者的比较参数主要是颗粒相最大沸腾高度 Hbm，实验粗略测得的高度约 为 140mm，模拟结果为 100mm，误差在 28.6%，而其余三种曳力模型的床层膨胀高 度无法达到应有的水平，数值模拟效果欠佳。根据二维数值模拟初步建立较为精确的 多相流模型，进一步模拟 43 个风帽的三维流化床反应器，在模拟结果欠佳的情况下， 对混合型网格和边界层类型网格的 7 风帽三维模型分别进行了数值模拟，最终得出网 格不同对模拟结果有较大影响的结论。 关键词：气固，流化床反应器，氧化铝，风帽，欧拉，数值模拟，实验 II II Abstract This study applies the eulers dual fluid model of computational fluid dynamics software Fluent 6.3.26 to simulate the 2D and 3D gas-solid fluidized bed reactor with 43 blast caps. The solid phase is alumina Particles, its diameter is 87.4μm and its true density is 3550kg/m3，it belongs to B-type . The gas phase is air under normal temperature 25℃， Its density is 1.185kg/ m3, and its dynamic viscosity is 1.835 ×10-5 Pa· S.In order to test the feasibility of numerical simulation project, we must do experimentation for fluidized bed reactor which has 30mm static powder bed and 30m3/h flow before implementing simulated. The physical model for numerical simulation is simplified by experiment model entirely. During 2D numerical simulation,the most important research is about the influence on fluidized state caused by four drag force models and two turbulence models . Final results show that, the amended syamlal-obrien drag force model has a good effect on numerical simulation, fluidized state tally with the actual situation. The main comParing Parameter between simunation and experiment is the maximum boiling height of Particles Hbm ,The experimental value is about 140mm, and the simulation results is about 100mm, the error is in 28.6 percent, but beds exPansion height of the rest three drag force cant attain th