Investigation of efficient film cooling configurations in realistically turbulent main flow

研究真实湍流主流中的高效气膜冷却配置

• 批准号: 324866747
• 负责人: Professor Dr. Michael Pfitzner
• 金额: --
• 依托单位: Institut für Thermodynamik (LRT-10)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/324866747?language=en
• 关键词: Investigation; efficient; film; cooling; configurations

The development of future, low emission gas turbine combustors requires efficient cooling concepts, which allow a wide range of options to control the combustion process due to a minimum consumption of cooling air. Applying new cooling configurations like the trench cooling, where the cooling air from the effusion jet is distributed laterally, the resulting film cooling efficiency can be considerably improved by up to one order of magnitude compared to simple effusion cooling. Up to now measurements were conducted at a main flow turbulence intensity of Tu = 1%. When exposing the trench geometry to the higher turbulence level of a real combustion chamber, the cooling efficiency might be reduced due to increased liftoff of the cooling air from the surface and premature mixing with the main flow.The main goal of the proposed research project is to achieve a deeper physical understanding of the detailed flow and heat transfer phenomena that occur in effusion cooling as compared to trench film cooling configurations through experimental and numerical investigations. The focus is on study of cooling films in a main flow of high turbulence characteristic for flows in real gas turbine combustion chambers. The effect of this increased main flow turbulence on the complex unsteady flow, mixing and heat transfer processes, as well as the resulting heat transfer coefficients and film cooling effectiveness will be studied experimentally and numerically.The experimental studies will use optical non-intrusive measurement technology. Besides standard techniques such as LDA and high speed PIV, novel measurement techniques will be optimized and applied. Using a combination of infrared and phosphorescence measurement techniques for measuring temperature boundary conditions, the distribution of the local heat transfer coefficient can be determined. Applying thermographic high speed PIV to the film cooling setup, time resolved simultaneous temperature and velocity distributions in the flow field can be measured. This allows the detailed examination of the complex unsteady flow structures and of the turbulent fluxes. The CFD simulations accompanying the experiment are performed using the commercial CFD code ANSYS Fluent with realizable k-epsilon model. For the detailed numerical studies of the effect of large eddies on the film structure and on the turbulent mixing, large eddy simulations will be performed using the open source CFD code OpenFOAM.

未来，低排放燃气轮机燃烧器的发展需要有效的冷却概念，这使得由于最少的冷却空气消耗而控制了燃烧过程。与简单的排放冷却相比，施加了新的冷却配置，例如沟渠冷却，横向分布来自积液喷气机的冷却空气，最多可以提高一个数量级。到现在为止，以TU = 1％的主要流量湍流强度进行了测量。当将沟槽几何形状暴露于真实燃烧室的湍流水平较高时，由于从表面上的冷却空气提高并与主流量过早混合，可能会降低冷却效率。拟议的研究项目的主要目标是通过实验和数值研究，与沟槽膜冷却构型相比，要对积液冷却中发生的详细流动和传热现象有了更深入的理解。重点是研究在真实燃气轮机燃烧室中流量的高湍流特征的主要流动中的冷却膜。这种增加的主要流动湍流对复杂流动流，混合和传热过程以及所得传热系数和膜冷却有效性的影响。实验研究将使用光学非侵入测量技术。 。除了LDA和高速PIV等标准技术外，还将优化和应用新颖的测量技术。使用红外和磷光测量技术来测量温度边界条件，可以确定局部传热系数的分布。可以测量热量高速PIV，在膜冷却设置中，可以测量流动场中的时间分辨出同时分辨的温度和速度分布。这允许对复杂的不稳定流量结构和湍流的详细检查。实验随附的CFD模拟使用具有可实现的K-Epsilon模型的商业CFD代码ANSYS进行进行。对于大涡流对膜结构和湍流混合的影响的详细数值研究，将使用开源CFD代码OpenFOAM进行大型涡流模拟。