Experimental and numerical investigation of the flow and heat transfer in conical Swirl Cooling Chambers

锥形涡流冷却室中流动和传热的实验和数值研究

• 批准号: 363548659
• 负责人: Professor Dr.-Ing. Bernhard Weigand
• 金额: --
• 依托单位: Institut für Thermodynamik der Luft- und Raumfahrt (ITLR)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/363548659?language=en
• 关键词: Experimental; numerical; investigation; flow; heat

The main goals in the development of industrial gas turbines and aero-gas turbines are the reduction of fuel consumption as well as the drastic reduction of pollutant emissions. This can be achieved, for example, by increasing the thermal efficiency of the gas turbine with the help of an increase in the process temperature. However, the increased combustion chamber temperature and the increased turbine inlet temperature are today already well above the melting temperature of the blade material, which makes it necessary to develop efficient turbine blade internal cooling strategies. Currently, various internal cooling concepts are being investigated in detail, such as ribbed channels, pin fins, impingement jets, dimples and cyclone cooling chambers. Cyclone cooling (swirl cooling or vortex tubes) are characterized by very high heat transfer rates. In the first funding period (FP1) of this project, vortex tubes with convergent tube cross-sections in the flow direction were investigated both experimentally and numerically. Here, a very good agreement between measurement results, such as the heat transfer measured with the transient liquid crystal technique and Detached Delayed Eddy Simulations (DDES) could be achieved. In addition, stability effects play an important role in heat and mass transfer processes. Therefore, the stability of the flow in the vortex tube was investigated using various stability criteria, with a focus on the stability criterion by Marsik, which is based on the second law of thermodynamics. In the current proposal for the second funding period (FP2), the investigations are now to be extended to cyclone cooling chambers with diverging cross-sections in the main flow direction. Due to the widening cross-sectional area in the direction of the flow, the swirl and the resulting detachment areas are significantly influenced. The flow is, thus, destabilized in a targeted manner. It is expected that the shaping will lead to higher heat transfer rates. Analogous to FP1, the flow and the heat transfer in the divergent cyclone cooling chambers will be investigated numerically by means of DDES and experimentally by means of PIV and the transient liquid crystal method. Furthermore, stability investigations for this geometry will again be carried out based on the second law of thermodynamics. At the end of the project, after six years, there will be detailed knowledge about the influence of convergent and divergent cross-sectional flows in swirl cooling chambers. This understanding of the very complex flow and heat transfer in convergent and divergent vortex tubes should help to successfully use such cooling systems for blade cooling in the future, for example in new types of gas turbine blades.

工业燃气轮机和航空燃气轮机发展的主要目标是降低燃料消耗以及大幅减少污染物排放。例如，这可以通过借助提高过程温度来提高燃气轮机的热效率来实现。然而，如今增加的燃烧室温度和增加的涡轮机入口温度已经远高于叶片材料的熔化温度，这使得有必要开发有效的涡轮机叶片内部冷却策略。目前，正在详细研究各种内部冷却概念，例如肋状通道、针翅、冲击射流、凹坑和旋风冷却室。旋风冷却（旋流冷却或涡流管）的特点是传热速率非常高。在该项目的第一个资助期（FP1），对流动方向上具有收敛管横截面的涡流管进行了实验和数值研究。在这里，测量结果之间可以达到非常好的一致性，例如使用瞬态液晶技术测量的传热和分离延迟涡模拟（DDES）。此外，稳定性效应在传热传质过程中发挥着重要作用。因此，利用各种稳定性准则研究了涡流管内流动的稳定性，重点是基于热力学第二定律的Marsik稳定性准则。在当前第二资助期（FP2）的提案中，研究现在将扩展到在主要流动方向上具有不同横截面的旋风冷却室。由于流动方向上的横截面积变宽，涡流和由此产生的分离区域受到显着影响。因此，有针对性地使流动不稳定。预计成形将导致更高的传热率。与 FP1 类似，发散旋风冷却室中的流动和传热将通过 DDES 进行数值研究，并通过 PIV 和瞬态液晶方法进行实验。此外，该几何形状的稳定性研究将再次基于热力学第二定律进行。 六年后，项目结束时，人们将详细了解旋流冷却室中会聚和发散横截面流的影响。对收敛和发散涡流管中非常复杂的流动和传热的理解应该有助于将来成功地使用此类冷却系统进行叶片冷却，例如在新型燃气轮机叶片中。