Unsteady flow and fluid-structure interactions in turbines with full- and partial admission

完全和部分进气的涡轮机中的非定常流动和流固相互作用

• 批准号: 254845878
• 负责人: Professor Dr.-Ing. Ronald Mailach
• 金额: --
• 依托单位: Professur für Turbomaschinen und Flugantriebe
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/254845878?language=en
• 关键词: Unsteady; flow; fluid; structure; interactions

Due to the increasing use of renewable energy sources, higher demands on the flexibility and part-load operation of steam turbines arise. Using a control stage, an efficient part-load operation of steam turbines can be realised. During part-load admission of the control stage, high velocity and pressure gradients between admitted and not admitted sections appear, which are responsible for unsteady flow conditions and a strong cyclic stress of the rotor blades. Very limited experimental investigations of these complex fluid- and structure-mechanical phenomena can be found in open literature. Numerical investigations of partial-admitted turbines are an appropriate tool for improving the physical understanding of these phenomena. However, a validation of the numerical codes using experiments is necessary, but restricted due the poor experimental data base available. In this project detailed experimental investigations in a large-scale axial air turbine will be performed. It is planned to combine flow investigations with a laser-optical measurement system, time-resolved measurements within the flow channel and at the sidewalls as well as measurements of the unsteady profile pressures on the rotor blades. Based on these detailed flow measurements the flow conditions will be described with high temporal and spatial resolution. For the first time, the influence of partial admission on the incoming flow field of the control stage, the interaction with the flow field within the blade passages as well as the time-resolved structure-mechanical excitation of the blades can be captured with combined experiment.In addition, transient 3D CFD-simulation using a commercial RANS-solver will be carried out and validated with the experiments. The numerical results will gain insight into flow details, which cannot be captured by the experiments or with too much effort, respectively. Further on, supplementary parameter variations are planned in order to improve the physical understanding and to check the application of the findings to other machines. By coupled fluid-mechanical / structural-mechanical investigations the excitation of the rotor blades due to the partial admission will be investigated.Aim of these investigations is to improve the physical understanding of the 3D time-resolved flow phenomena as well as fluid-structural interactions due to partial admission in steam turbines. In future, the results of this project will contribute to an improved design process of steam turbines for higher operational flexibility and improved efficiency for part-load operation, necessary for forthcoming generations of these turbomachines.

由于可再生能源的使用不断增加，对汽轮机的灵活性和部分负荷运行提出了更高的要求。使用控制级，可以实现蒸汽轮机的高效部分负荷运行。在控制级部分负荷进入期间，进入和未进入部分之间出现高速度和压力梯度，这是造成不稳定流动条件和转子叶片的强循环应力的原因。在公开文献中可以找到对这些复杂的流体和结构力学现象的非常有限的实验研究。对部分接纳的涡轮机的数值研究是提高对这些现象的物理理解的适当工具。然而，使用实验对数字代码进行验证是必要的，但由于可用的实验数据库较差而受到限制。 在该项目中，将对大型轴流式空气涡轮机进行详细的实验研究。计划将流动研究与激光光学测量系统、流道内和侧壁的时间分辨测量以及转子叶片上的非稳态轮廓压力的测量结合起来。基于这些详细的流量测量，将以高时间和空间分辨率描述流量条件。首次可以通过组合实验捕获部分进气对控制级进入流场的影响、与叶片通道内流场的相互作用以及叶片的时间分辨结构机械激励。此外，将使用商用 RANS 求解器进行瞬态 3D CFD 模拟并通过实验进行验证。数值结果将深入了解流动细节，而这些细节无法通过实验或花费太多精力来捕获。此外，还计划补充参数变化，以提高物理理解并检查研究结果在其他机器上的应用。通过耦合流体-机械/结构-机械研究，将研究由于部分进气引起的转子叶片的激励。这些研究的目的是提高对 3D 时间分辨流动现象以及由于汽轮机中部分进气引起的流体-结构相互作用的物理理解。未来，该项目的成果将有助于改进蒸汽轮机的设计过程，以提高操作灵活性并提高部分负荷操作的效率，这是下一代涡轮机所必需的。