论文总字数：24174字

摘 要

随着离心泵应用范围的不断扩大，离心泵的优化设计需求也在不断增加。吸水室是泵的重要部件之一，吸水室内部的流动状态将直接影响到泵的整体性能，因此，优化吸水室的结构以提高离心泵的性能具有着十分重要的意义。通过使用CFD数值模拟技术，对型号为IS 80-50-250的离心泵进行研究分析。揭示了不同锥角的吸水室对泵性能的影响，并对平直形吸水室内部的速度流线与压力的变化规律以及平直形吸水室内导流板的参数与泵的性能之间的关系进行了分析，确定了0.6Q时导流板的最佳设计参数。研究结果可为离心泵的性能提升以及吸水室结构的改进提供参考价值。

本文主要研究工作与结论如下：

（1）简述了课题研究的背景、意义及国内外发展趋势，详细地介绍了模型泵的三维建模、网格划分以及数值模拟的方法，确定了最佳网格数量为1624798个；控制方程选取N-S（纳维-斯托克斯）方程；湍流模型选用RNG k-ε；动静区域流动的耦合选用多重参考系模型方法。

（2）研究了直锥形吸水室的锥角对泵性能的影响，详细分析了平直形吸水室内部流动的速度流线与压力分布规律。结果表明，在额定工况下，使用平直形吸水室的离心泵其扬程和效率要明显高于另外两种吸水室，并且此时的流线与压力分布最为均匀和稳定；液体流量较小时，吸水室内部流场较为紊乱。

（3）研究了平直形吸水室内增设导流板对泵性能的影响，对导流板的轴向长度、径向长度、导流板厚度、导流板距离吸水室出口截面的距离、导流板的数量以及安装角度等参数与泵扬程和效率之间的关系进行了详细地分析。结果表明，0.6Q时，导流板的最佳设计参数为l_a=60 mm、l_r=15 mm、δ=4 mm、l_pa=5 mm、n_p=2个、以及β=30°。

关键词：离心泵 吸水室 锥角 数值模拟 导流板

ABSTRACT

With the expansion of the application range of centrifugal pump, the demand for optimized design of centrifugal pump also increases. The suction chamber is one of the important parts of pump. The flow state of the suction chamber will have a direct impact on the whole performance of the pump. Therefore, it is of great significance to optimize the structure of the suction chamber to improve the centrifugal pump. The centrifugal pump IS 80-50-250 was studied and analyzed by CFD numerical simulation. The influence of suction chamber with different cone angles on pump performance was revealed, and the change law of velocity streamline and pressure variation in the flat suction chamber was revealed. A link between baffle’s parameters in the flat suction chamber and the pump’s performance was analyzed. The optimal design parameters of the guide plate at 0.6Q were determined. The results provide a reference value for improving the centrifugal pump and improving the structure of the suction chamber.

The following are the main research contents and conclusions of the dissertation:

(1) The background, significance and research trends at home and abroad were briefly introduced, and the 3D modeling, grid division and numerical simulation methods of the model pump were introduced in detail. The optimal number of grids was 1624798. The N-S (Navier-stokes) equation was selected as the governing equation. RNG k-ε turbulence model was used. The multi reference frame model was utilized for the coupling of the static flow area.

(2) The influence of the direct cone angle of the cone-shaped suction cavity on the pump flow was studied. The velocity streamline and pressure distribution of the rectangular suction cavity described in detail. The results show that under rated conditions, the head and efficiency of the centrifugal pump with a flat suction chamber are significantly higher than those of the other two, and the streamline and pressure distribution are the most uniform and stable at this time. When the liquid flow rate is small, the flow distribution inside the suction chamber is disordered.

(3) The effect of the baffle on the performance of the pump was studied. The relationship among the axial length of the baffle, radial length, the thickness of the baffle, the distance between the baffle and the outlet section of the suction chamber, the number of baffles, installation angle of the baffle and the pump head and efficiency was analyzed in detail. The results show that at 0.6Q, the optimal design parameters of the baffle are l_a=60 mm, l_r =15 mm, δ= 4 mm, l_pa=5 mm, n_p=2, and β=30°.

Keywords: Centrifugal pump; Suction chamber; Cone angle; Numerical simulation; Baffle

目 录

摘 要 I

ABSTRACT i

第一章 绪论 1

1.1 课题研究的背景 1

1.2 课题研究的意义 2

1.3 课题研究现状 2

1.3.1 离心泵直锥形吸水室研究现状 2

1.3.2 CFD技术在离心泵内部流动数值模拟的研究现状 3

1.4 课题发展趋势 3

1.4.1 吸水室结构的优化设计 4

1.4.2 吸水室内导流板的优化设计 4

1.4.3 吸水室内流型的研究 4

第二章 吸水室内部流动数值模拟方法 7

2.1 流体域Pro/E实体建模 7

2.2 网格划分及独立性验证 7

2.2.1 网格划分 7

2.2.2 网格独立性验证 8

2.3 控制方程及湍流模型 9

2.3.1 控制方程 9

2.3.2 湍流模型 9

2.4 CFD数值模拟方法 11

2.4.1 计算方法 11

2.4.2 边界条件 12

2.5 本章小结 12

第三章 吸水室形状对泵性能的影响及其内部流动分析 13

3.1 锥角大小对泵扬程和效率的影响 14

3.2 平直形吸水室内部流线图 16

3.3 平直形吸水室内部流场压力分布 18

3.4 本章小结 19

第四章 吸水室内增设导流板对泵性能的影响 21

4.1 轴向长度l_a的影响 21

4.2 径向长度l_r的影响 23

4.3 厚度δ的影响 24

4.4 距离吸水室出口截面的距离l_pa的影响 24

4.5 导流板数量n_p的影响 25

4.6 安装角度β的影响 27

4.7 本章小结 28

第五章 经济性评价 29

第六章 结论与展望 31

5.1 结论 31

5.2 展望 31

参考文献 33

致 谢 37

第一章 绪论

1.1 课题研究的背景

离心泵作为一种流体机械，在石化、矿业、供水、消防和农业等诸多生产部门都有着广泛应用^[1]。泵在运行过程中将电机的机械能传递给泵内流体，使得流体的能量增加^[2]。泵的主要过流部件有吸水室、叶轮、蜗壳和压水室。泵的吸水室在叶轮前端，流体流经吸水室到达叶轮。吸水室的结构可分为直锥形、弯管形、环形和半螺旋形等。流体在吸水室中的速度较低，故而水力损失相比其他过流部件也较小，但吸水室内的流动状态将对叶轮及其后面流道的流动情况产生直接影响，进而影响到泵的效率及汽蚀性能^[3]。

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