Influence of local air extraction due to film cooling on the flow field and heat transfer in cooling channels with variation of rib geometry and position

随着肋条几何形状和位置的变化，气膜冷却引起的局部抽气对冷却通道流场和传热的影响

基本信息

批准号：
255351625
负责人：
Professor Dr.-Ing. Konrad Vogeler
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 2019-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/255351625?language=en
关键词：
Influence local air extraction due

项目摘要

The goal of the applying project is to increase the understanding of flow physics in a multipass cooling channel and its manipulation. In the frame of a systematic investigation the influence of the position of film cooling holes within a ribbed cooling channel for discrete rib geometries will be analyzed. The resulting knowledge will lead to an improvement of internal heat transfer and therefore blade cooling.Previous work at the Chair shows the influence of the cooling air extraction on the internal heat transfer for specific rib positions. It can be expected, that in more engine-like configurations, with multiple successive rib segments with cooling air extraction, the effects of the single holes will influence and possibly amplify each other. Further the ribs in real turbine blades have an inclination leading to a secondary flow within the rib passage. The increased turbulence and additional vortices result in a locally intensified heat transfer in comparison to straight ribs. Therefore the question arises, if a specific position of the cooling holes in axial and lateral direction will allow a positive influence of the secondary flows and heat transfer. The successful concept of the hole positioning will be adopted to inclined and V-type ribs.The main questions of the investigation are, how the position of the cooling air extraction can manipulate the flow field within the rib passage, which is dominated by the secondary flow, and what this means to the heat transfer. These questions will be examined under the interaction of successive rib segments. The results of the proposed work will enhance the physical understanding of the interaction of the flow field around ribs and the film cooling extraction within a cooling channel. If the expectations are fulfilled, the results derived for the research can be implemented into future design rules for gas turbine cooling systems. This will improve the usage of the available cooling air and whole cooling system. A higher efficiency and life time of the turbine will be achieved. For the overall system this results in lower fuel consumption and emissions.

应用项目的目的是增加对多通冷却通道中流动物理的理解及其操纵。在系统调查的框架中，将分析膜冷却孔在肋骨冷却通道内的位置进行离散肋几何形状的影响。由此产生的知识将导致内部热传递的改善，因此会改善叶片冷却。椅子上的预防作品显示了冷却空气提取对特定肋骨位置的内部热传递的影响。可以预见的是，在更类似发动机的配置中，具有多个连续的肋骨段带有冷却空气提取，单孔的效果将影响并可能相互扩大。此外，真实涡轮叶片中的肋骨具有倾斜度，导致肋骨通道内的二次流动。与直肋相比，增加的湍流和其他涡旋导致局部加剧的传热。因此，问题出现了，如果冷却孔在轴向和横向方向上的特定位置将允许次级流和热传递的积极影响。孔定位的成功概念将用于倾斜和V型肋骨。调查的主要问题是，冷却空气提取的位置如何操纵肋骨通道内的流场，这是次要流动的主导，这意味着热传递。这些问题将在连续的肋骨段的相互作用下进行检查。提议的工作的结果将增强对肋骨周围流场相互作用的物理理解，以及在冷却通道内的膜冷却提取。如果满足期望，则可以将研究得出的结果实施到燃气轮机冷却系统的未来设计规则中。这将改善可用冷却空气和整个冷却系统的使用。将实现较高的效率和寿命。对于整个系统，这会导致燃料消耗和排放量降低。