Experimental measurements of ingress and heat transfer in gas turbines

这项研究是在巴斯大学涡轮机械研究中心(TRC)内进行的。这是一个研究燃气轮机进气和换热的试验性项目。西门子已经提供了iCASE奖学金来支持这个项目。燃气轮机的入口是发动机设计者面临的最重要的冷却空气问题之一，国际上已经投入了大量的研究工作来寻找可接受的设计标准。当来自主流气体路径的热气体被吸入涡轮盘与其相邻机壳之间的轮隙时，就会发生这种情况。在系统的外围安装了轮缘密封件，并使用冷却液的密封流来减少或防止进入。然而，太多的密封空气会降低发动机的效率，太少的密封空气会导致严重的过热，导致涡轮轮缘和叶片根部受损。巴斯大学的叶轮机械研究中心(TRC)在过去11年里通过实验、理论和计算研究了进口的影响。这项研究是在EPSRC共同资助的两个非常成功的项目上与西门子合作进行的。这两个项目都涉及设计和制造全仪表式转盘钻机，用于研究发动机代表的燃气轮机车轮空间的入口影响。与实验方案并行，巴斯开发的理论模型已被广泛用于分析和解释从试验台获得的测量数据。建议将这项研究扩展到调查典型工业发动机设计中的两级涡轮定子井结构中入口的影响。旋转圆盘表面的温度测量将被用来确定存在入口时的绝热效率和换热系数。重点将侧重于转化Bath的一个单独项目(EP/P003702/1)中的实验和分析技术，该项目研究压缩机转子盘内的热传递。开发的理论模型能够准确地确定稳态Nusselt数及其可信区间。将利用现有的Bath旋转钻机进行可行性研究，以开发想法和仪器。拟议的项目将首次将新的分析方法和改进的测量技术能力应用于涡轮盘换热试验。这名博士生将协助博士后助理设计、建造和调试试验台，并在进行实验测量方面发挥主导作用。旋转圆盘表面的温度测量将被用来确定存在进气时的绝热效率和换热系数。通过改进发动机设计成功完成和实施这项研究，将为西门子带来竞争优势。

The research is within the Turbomachinery Research Centre (TRC) at the University of Bath. It is an experimental project investigating ingress and heat transfer in gas turbines. A iCASE studentship has been provided by Siemens to support this project.Ingress in gas turbines is one of the most important of the cooling-air problems facing engine designers, and considerable international research effort has been devoted to finding acceptable design criteria. It occurs when hot gas from the mainstream gas path is ingested into the wheel-space between the turbine disc and its adjacent casing. Rim seals are fitted at the periphery of the system, and a sealing flow of coolant is used to reduce or prevent ingress. However, too much sealing air reduces the engine efficiency, and too little can cause serious overheating, resulting in damage to the turbine rim and blade roots.The Turbomachinery Research Centre (TRC) at the University of Bath has investigated the effects of ingress experimentally, theoretically and computationally over the last 11 years. This research has taken place in collaboration with Siemens across two highly successful projects jointly funded by the EPSRC. Both of these projects involved the design and manufacture of fully-instrumented rotating disc rigs used to study the effects of ingress in engine-representative gas-turbine wheel-spaces. In parallel with the experimental programmes, theoretical models developed at Bath have been used extensively in the analysis and interpretation of the measured data obtained from the rigs.It is proposed to expand this study to investigate the effects of ingress in a two-stage turbine stator well configuration, representative of a typical industrial engine design. Temperature measurements on the rotating disc surfaces will be used to determine the adiabatic effectiveness and heat transfer coefficients in the presence of ingress. Emphasis will be placed on translating experimental and analytical techniques from a separate project at Bath (EP/P003702/1) investigating heat transfer in compressor rotor discs. A theoretical model developed enables the steady-state Nusselt numbers, and their confidence intervals, to be accurately determined.Feasibility studies will be conducted using the existing Bath rotating rigs to develop ideas and instrumentation. The proposed project will, for the first time, apply new analysis methods and improved measurement technique capability to heat transfer tests on turbine discs. The PhD student is expected to assist a postdoctoral research associate in the design, construction and commissioning of the test rig, and take a leading role in conducting the experimental measurements. Temperature measurements on the rotating disc surfaces will be used to determine the adiabatic effectiveness and heat transfer coefficients in the presence of ingress.The successful completion and implementation of this research through improved engine design should result in a competitive advantage for Siemens.