【作者】 杨昌明；

【导师】 陈次昌； 王金诺；

【作者基本信息】 西南交通大学 ， 机械设计及理论， 2003， 博士

【摘要】 据对轴流式压气机的研究，由叶顶间隙引起的间隙流动影响着流场的结构与流动损失的分布，影响着机器的效率，因此这一影响因素在进行三维气动设计时应予以充分的重视与考虑。间隙流动将导致损失增加，改变出流条件，正确预测这一流动现象对进一步提高压气机转子的效率有着重要的意义。 泵是应用广泛的通用机械之一，其中轴流泵占有相当大的比例。据文献介绍，我国轴流泵水力模型的效率，从总体上看比国外先进水平低(1-3)％。而由于对泵内真实流动现象，特别是叶片顶部间隙区流动的研究还不深入，显然不能满足高性能轴流泵设计的需要。对于轴流泵，类似的研究在国内外还不多见。因此，为了深入考察叶顶间隙对泵内流场及性能的影响，本文进行了轴流泵间隙流动数值模拟与试验的研究。 采用激光测速仪LDV，对轴流泵叶轮内部及进出口旋转流场进行了流动测量研究。在LDV应用接口基础上，完成了轴编码器系统的开发，实现了周期多点采样和连续测量，解决了轴流泵内部旋转流场LDV试验中测点周向定位及锁相位测量的难点问题。编制的轴流泵LDV实验数据处理程序，可以自动提取测试数据，提供相关图表、曲线、图形，从而能够直观观察流动现象，评估流动状况，考察流动特性。 提出了FLUENT／GAMBIT平台上基于组件(COM)的轴流泵参数化三维造型方法。提出了多项式拟合方法，解决了由有限翼型截面拟合光滑叶片表面的关键问题。造型程序采用COM技术与OLEDB数据接口，以翼型数据库为基本参数，实现了轴流泵的自动建模。参数化造型方法根据流体动力学仿真软件FLUENT的特点，保证了造型的精确性，避免了交互式取点造型的复杂过程，是一种有效的适合数值模拟的几何建模方法，能够满足轴流泵三元流动数值模拟要求。 采用FLUENT，以雷诺平均N-S方程为流动控制方程，标准k-ε模型为湍流模型，SIMPLEC算法求解压力速度耦合问题与非结构化网格划分技术，进行了多种间隙与多种工况下的轴流泵叶轮内部三元流动的数值模拟研究，通过试验对照，表明计算方法可靠、有效。同时，对叶轮出口轴向速度、径向速度分布、过叶片转动中心的轴面速度矢量、叶片背面压力分布和叶端附近流态进 西南交通大学博士研究生学位论文第11页行了重点分析。在三维数值模拟的基础上，建立了考虑粘性及间隙影响的轴流泵叶轮水力性能的预估模型。该方法能够反映叶轮的性能特性，可用于轴流泵的性能预测及叶轮几何参数的优化，从而能为轴流泵的水力设计提供依据。 通过三维参数化造型建立过流部件实际流道的几何模型，采用FLUENT进行数值模拟，结合LDV试验对照，建立水力性能预估模型，形成了一种研究轴流泵内部复杂流动现象的系统方法。更多还原

【Abstract】 The influence factor of clearance flow through the tip clearance needs considering in three-dimensional aerodynamic design, due to clearance flow’s influence on the structure of flow fields, distribution of flow loss, and efficiency of machine, according to study of axial flow compressor. Clearance flow causes large efficiency loss. Clearance flow also changes the condition of exit flow. Therefore, it is important for designers to predict the clearance flow phenomena accurately, for further improving efficiency of axial flow compressor.Pump is a kind of general machinery, in which axial flow pump is used extensively. Hydro efficiency of domestic axial flow pump is lower than foreign advanced level. Present study of real flow phenomenon in pump cannot meet the design of high performance axial flow. Similar study of axial flow pump has not been reported. Therefore, the study of numerical simulation and experimental investigation on clearance flow in axial flow pump is carried out in order to investigate the influence of tip clearance on flow fields and performance.Flow measurements are made before, inside, and behind an axial flow rotor by LDV. Based on the application interface of LDV, coding system is developed, periodic multi-sampling and continuous measurement are realized, and the difficult problem of circumferential locating and phase locking is solved. The experimental data processing procedure can automatically process data, provide relevant chart, curve and graphics, thus flow phenomena, flow condition, and flow behavior can be investigated through the senses.A parametric modeling method of axial flow pump is put forward based on COM. A polynomial fitting approach is presented, and thus the key question of fitting smooth blade surface from limited airfoil section is solved. Automatic modeling of axial flow pump is realized through basic parameter in airfoil database and the modeling software that adopts COM technology and OLE DB interface. Parametric modeling method, which ensures the precision of model, avoids the complex process of interactive modeling, is an effective geometry setup methodwhich adapts numerical simulation of three-dimensional flow in axial flow pump.Three-dimensional flow in axial-flow pump is simulated based on Reynolds-averaged N-S equations, standard k-e turbulence model, SIMPLEC algorithm, and unstructured mesh. The numerical simulation is done with various work conditions and tip clearance by FLUENT. The calculative method is reliable and effective through the validation by experimental data. At the same time, velocity distribution at the exit of rotor, velocity vectors at the axial plane through rotating center, pressure contour on the suction surface of the blade and flow behavior are analyzed in detail. The predict model of hydro-performance of axial flow pump is established on the basis of numerical simulation. The model can reflect the performance character of rotor, predict performance of axial flow pump, optimize geometry parameter of rotor, and provide basis for hydro design of axial flow pump.To setup geometry model of wetted parts through parametric modeling method, simulate flows using FLUENT, compare numerical result with LDV experiment, and establish predict model of hydro performance formed a system approach which studies complicated flow phenomena in axial flow pump.更多还原