Experimental Investigation of Gas Turbine Aerodynamics using Planar Laser-Induced Fluorescence (PLIF).

将进行一项实验性博士课程，目的是研究燃气涡轮机中的空气动力学，特别是吹扫流对主流空气动力学的影响。由于涡轮机中存在高温，任何流入盘腔（涡轮机的固定部件和旋转部件之间的空间）的热空气都可能对涡轮机造成严重损坏，并导致效率损失，这种流动称为进入。为了抵消这种冷却空气/吹扫气流，通过阀瓣腔引入冷却气流，这被称为出口气流。出口流在被引入主流流中时引起空气动力学损失，从而导致涡轮机效率降低。近年来，以Martin G Rose博士为主的几位研究人员对现代燃气轮机端壁造型（EWC）设计技术进行了研究，该技术改变了定子叶片和转子叶片之间的静压场。理论上，EWC（如果操作正确）可通过减少转子叶片周围形成的涡流和横流，更有效地重新引入出口气流。此外，EWC可以通过减小定子和转子上的静压差来减小出口流量，从而导致吹扫流的较低压力，并因此导致较低流速。这将通过使用巴斯大学新建造的大型环形装置（LAR）和使用平面激光诱导荧光（PLIF）技术来研究流动轨迹。这将补充PIV（三分量体积测速法）测量，该测量检查速度场，以给出吹扫流对主流空气动力学的影响的清晰图像。该项目将研究不同的EWC剖面，以确定它们在减少出口流、减少吹扫流与主流混合的气动损失以及二次流损失方面的有效性。该项目的总体目标是通过边缘密封出口几何形状和EWC的组合设计来提高燃气涡轮机的气动效率。该项目还与西门子公司合作，将借鉴他们的丰富经验。

An experimental PhD programme will be conducted with the aim of investigating the aerodynamics in a gas turbine, specifically the effect of purge flow on the mainstream flow aerodynamics. Due to the high temperatures found in turbines any hot air that flows into the disc cavity, the space between the stationary components and rotating components of the turbine, can cause serious damage to the turbine and also results in a loss of efficiency, this flow is called ingress. To counteract this cooling air/purge flow is introduced through the disc cavity to cool the ingress flow, this is called egress flow. Egress flow causes aerodynamic losses when introduced into the mainstream flow resulting in a reduced turbine efficiency. The design technique in modern gas turbines of end wall contouring (EWC) which alters the static pressure field between the stator vanes and rotor blades has been investigated by several researchers in recent years mainly by Dr Martin G Rose. EWC if done correctly could theoretically be used to reintroduce egress flow more efficiently by reducing the vortices and crossflow formed around the rotor blades. Also EWC could reduce the amount of egress flow by reducing the static pressure difference across the stator and rotor, resulting in a lower pressure of the purge flow and as a result a lower flowrate. This will be researched by using the newly constructed large annulus rig (LAR) at the University of Bath and using planar laser-induced fluorescence (PLIF) techniques to examine the flow trajectory. This will complement the PIV (three component Volumetric Velocimetry) measurements which examine the velocity field, to give a clear picture of the effect of the purge flow on the mainstream flow aerodynamics. The project will investigate different EWC profiles to determine their effectiveness at reducing egress flow, reducing the aerodynamic losses from the mixing of the purge flow with the mainstream flow and the secondary flow losses. The overall aim of the project is to improve the aerodynamic efficiency in a gas turbine by a combined design of rim seal exit geometry and EWC. The project is also in association with Siemens and will draw on their extensive experience.