摘要：本课题使用ANSYS软件研究内外双螺带组合桨搅拌槽的同轴异速流体混合特征以及整体流体运动情况。以两种螺带桨叶构型为基础，分别置于同一轴上进行搅拌。分别对同向、异向旋转的同轴双螺带搅拌器的不同转速比下进行模拟运算，得到各种不同条件下的流体流场速度分布图、混合均匀时间、剪切应变速率分布、最大剪切应变速率、体积平均剪切率、轴功率等数据。结果分析表明，同轴内外螺带搅拌器在异向操作转速比为1的情况下表现出最佳的混合效果，其可以在螺带速度且功率较低条件下，拥有很高流体速度区域。在其他不同转速比的情况下，转速比越高则平均剪切速率也越高，轴功率越大，剪切应变速率在内外异向搅拌的情况下会更大。 79841

毕业论文关键词：同轴异速桨叶；内外螺带；计算流体力学；混合特征；轴功率

Abstract：In this study, ANSYS analysis software was used to simulate the mixing and fluid motion in coaxial mixer。 The flow field was obtained by computational fluid dynamics method。 Based on the two kinds of helical ribbon configuration, they were placed on the same axis for stirring。 The conditions of the different speed ratios of 1, 2, 4, 6 and 8 were calculated respectively。 The fluid flow field under different conditions was obtained。 Velocity distribution, mixing time, shear strain rate distribution, maximum shear strain rate, volume average shear rate, power consumption and other data were obtained。 The results show that the counter-rotating of the coaxial inner and outer helical ribbon has the best mixing performance in the case of speed ratio of 1, which can be carried out under the condition of low speed and low power, showing a high fluid velocity region。 In the case of other different speed ratios, the higher the speed ratio was, the higher the average shear rate and the higher the shaft power。 The shear strain rate was higher in the counter-rotating mode than that in co-rotating mode。

Key Words：Coaxial impeller; inner and outer helical ribbon; computational fluid dynamics; mixing characteristics; power consumption

目  录

1 发酵罐的流体模拟运算技术 1

1。1 计算流体力学(CFD)技术概况 1

1。2 组合搅拌槽结构现状 1

1。3 搅拌槽内数值模拟现状 1

1。4 搅拌槽的数值模拟方法 2

1。4。1 多重参考坐标系法(Multi-Reference Frame，MRF) 2

1。4。2 滑移网格法(Sliding Mesh) 3

1。5 螺带型搅拌槽轴功率的相关计算 4

2 研究目的、意义以及内容 5

2。1 研究目的 5

2。2 研究意义 5

2。3 研究内容 6

3 数值模拟方法 6

3。1 流体力学控制方程 6

3。2 数值计算方法