Periodical unsteady flow near the endwalls of rotating compressor bladings

目前涡轮机械中增加压力比、减少叶片数、减小展弦比、剧烈的部分负荷运行等努力导致了侧壁附近流动对发动机整体性能的影响越来越大。特别是工作范围、损失和传热受到这些流动的影响。虽然经过几十年的研究，但发生的机制尚未完全理解。因此，当前的技术进步强烈要求充分的基础研究活动。这一缺陷将由德累斯顿工业大学、慕尼黑大学和波鸿大学四个研究小组的联合研究计划来解决，通过仔细协调模拟和实验来产生相关结果。除了研究传热和开发有条理的工具外，这个联合项目的一个主要目标是详细分析系统旋转的影响。因此，一些特别规划和调整的配置将被调查和相互比较。在德累斯顿工业大学涡轮机械和飞行推进主席项目部分的框架内，将分析压气机转子端壁附近的流动，并与静止叶栅进行比较。通过在低速研究压气机上适当的试验装置，将线性静止叶栅和旋转压气机转子之间的不同的逐步抽象分别用于评估旋转、科里奥利力、随叶片高度增加的螺距、径向压力梯度、端壁相对运动和入口边界层剪切的影响。实验研究将涵盖静止环形叶栅（定子）的测量，包括与旋转/非旋转轮毂端壁有径向间隙和没有径向间隙的测量，以及有和没有尾流发生器的旋转环形叶栅（转子）的测量，以模拟转子-定子-相互作用。所有构建和附加参数变化将通过RANS和URANS模拟进行数值模拟。本工作包的目标是改进对单个参数影响的物理理解，通过RANS方法验证其预测，并确定不同数值方法的优缺点，特别是与德累斯顿工业大学流体力学主席的项目部分选择的测试用例的LES进行比较。此外，压气机和涡轮配置的现象将与慕尼黑和波鸿的研究伙伴进行比较和讨论。

Current efforts in turbomachinery to increase pressure ratio, reduce blade count, decrease the aspect ratio, intense part load operation, etc. lead to increasing influence of flows near the side walls on the overall engine performance. Especially the operating range, losses and heat transfer are influenced by these flows. The occurring mechanisms are not fully understood although being investigated since decades. Thus the current technological progress strongly requests adequate basic research activity. This deficit will be addressed by a joint research program of four research groups at TU Dresden, UniBw München und RU Bochum, by carefully coordinated simulations and experiments to produce relevant results. Beside the investigation of heat transfer and the development of methodical tools a major goal of this joint program is the detailed analysis of the effect of system rotation. Therefor a number of specially planed and adjusted configurations will be investigated and compared with each other.In the framework of the project part at the Chair for Turbomachinery and Flight Propulsion at TU Dresden the flow near the endwall of a compressor rotor will be analyzed in comparison with stationary cascades. Through appropriate test assemblies at the Low Speed Research Compressor distinct stepwise abstractions between a linear stationary cascade and the rotating compressor rotor will be introduced to evaluate the effects of rotation, Coriolis force, increasing pitch with blade height, radial pressure gradients, relative motion of the end walls and shear of the inlet boundary layer separately. The experimental investigation will cover measurements at a stationary annular cascade (stator) with and without radial clearance to the rotating / non-rotating hub endwall and a rotating annular cascade (rotor) with and without wake generator for simulation of the rotor-stator-interaction. All builds and additional parameter variation will be numerically modelled by RANS and URANS simulations. The target of this work package is an improvement of the physical understanding of the influence of the single parameters, a validation of their prediction by RANS methods and a determination of the strength and weaknesses of different numerical approaches especially in comparison with the LES of selected test cases by the project part at the Chair of Fluid Mechanics at TU Dresden. Furthermore the phenomena in compressor and turbine configurations will be compared and discussed together with the research partners in Munich and Bochum.