Numerical and Experimental Investigation of Secondary Flow and Loss Generation in Inducers

如果不考虑B. Lakshminarayana（1996）的图片，到目前为止还没有关于诱导叶轮二次流的定量研究。B. Lakshminarayana的图片只提供定性图片，不包含单个区域的范围信息（3d边界层、3d分隔线、奇异点、核流等）。叶片、轮毂和机匣上的二次流图不包括在内。这种知识差距将由预期的项目来弥补。将对几个诱导体进行CFD流动模拟，并对二次流进行描述。通过测量（性能和现场测量）和油图来验证CFD结果。此外，还需要查明实际设计规则是否适合确定诱导轮的轴向长度。对于轴向长度的确定，Li的奇异性方法提供了一种合适的方法，尽管从申请人的角度来看，损失模型是不够的。目的是：1)通过cfd模拟，确定80%、100%和120%（最佳效率点）的三维边界层的流动拓扑。申请人意识到，通过CFD只能部分实现这一目标。但是申请人在一个成功关闭的dfg项目中成功地将压气机叶栅的实验和数值油图结合在一起，因此他认为尽管他非常清楚这种方法的缺点，但它将有效。2)流动拓扑由实验油图确定。因此，油漆（公司：Leinos类型：Natural-White，编号820，密度：1.19 g/cm³）将与石油（密度约为0.85g/cm³）混合，使混合物具有接近水的密度。在椅子上进行了SAM调查，以测试该方法的可行性，结果令人满意。该方法也应用于布伦瑞克工业大学普莱德勒研究所（今天的IFAS）的轴向叶轮泵。3)确定前缘掠度对轮毂区域流动拓扑的影响。申请人假设后掠前缘对轮毂边界层的流动拓扑有明显的影响，但对流动损失的影响很小。

Until now there are no quantitative investigations about secondary flow in inducer impellers, if the pictures of B. Lakshminarayana (1996) are not taken into account. B. Pictures of Lakshminarayana only provide a qualitative picture and contains no information about the extent of single regions (3D-boundary layer, 3D-separation lines, singular points, kernel flow etc.). Secondary flow pictures on blades, hub and casing are not included. This knowledge gap is to be closed by the intended project. CFD flow simulations are to be performed for several inducers and the secondary flow is to be depicted. By measurements (performance- and field measurements) and oil pictures the CFD results are to be validated. Furthermore it is to be found out whether the actual design rules are appropriate to determine the axial length of an inducer. For the determination of the axial length the singularity method of Li provides a suitable method, although the loss model is insufficient from the applicant point of view. The aims are: 1) By CFD-simulations the flow topology of the three-dimensional boundary layer is to be determined for 80%, 100% and 120% (Best Point of Efficiency). The applicant is aware that by CFD this aim can be reached only partly. But the applicant succeeded in bringing together experimental and numerical oil pictures of compressor cascades in a successfully closed DFG-Project, so that he is of the opinion that it will work although he knows very well the shortcomings of this method. 2) The flow topology is to be determined by experimental oil pictures. Therefore oil paint (Company: Leinos Typ: Natural-White, Nr. 820, Density: 1,19 g/cm³) is to be mixed with petroleum (density approximately 0.85g/cm³) so that the mixture possesses nearly the density of water. At the chair SAM investigations were performed in order to test the feasibility of this method which shows satisfactory results. This method was also applied for an axial impeller pump at Pfleiderer Institute of TU Braunschweig (today IFAS). 3) The influence of sweep of the leading edge on the flow topology of the hub region is to be determined. The applicant supposes that the swept leading edge has an identifiable influence on the flow topology of the hub boundary layer, but that the influence on the flow losses is small.