Active control of fluid flows in gas turbines

随着各国的工业化和世界人口的增长，全球对电力和高效交通的需求只会增加。这个应用程序是关于使发动机更有效地使用改变游戏规则的技术，使复杂的计算机控制发动机热力学循环。这项研究将解决计算机控制发电流体流动所需的技术构建模块。调节发动机流量的技术困难可能是巨大的，但控制的好处是巨大的。例如，燃气轮机叶片尖端的泄漏流和燃烧室的冷却气流分别对发动机燃料燃烧和排放有重要贡献。许多这样的发动机流是高速、高压（20bar+）和高温（500℃+），并且存在于发动机难以接近的部件中。这意味着具有活动部件的传统阀门和执行器由于寿命不足和响应时间慢而不可行。在这里，我们将考虑一种新的阀门概念，它没有活动部件，在通常用于燃气轮机或柴油发动机的压力和温度下工作。本研究所研究的电流体晶体管阀，是利用微小的等离子体放电结合基本流体效应，在指令时注入或关闭气流。本研究的目标之一是了解影响此类设备操作和性能的基本参数。这种设备的运行速度有多快？如何利用控制工程直接在微观尺度上操纵涡轮叶片尖端的气流这是航空发动机效率低下的最大因素？为了回答这些问题，这项雄心勃勃的提案采用了一种综合方法，将研究等离子体开关流体阀的科学，确定高带宽流量控制的关键控制规律和架构，然后在具有挑战性的高速涡轮应用中实验证明这一概念。这需要控制工程师和热流体专家之间的密切研究合作，这一方向与EPSRC控制工程和空气动力学学科的战略非常一致。申请人相信，这种多渠道的方法是推动这种潜在的颠覆性技术进入二氧化碳减排应用的最佳途径。

The global appetite for power and for efficient transportation can only increase as nations industrialise and the world's population grows. This application is about making engines more efficient using game changing technology that enables sophisticated computer control of engine thermodynamic cycles. This research will address the technological building blocks required for computer controlled manipulation of power generating fluid flows. The technical difficulties of modulating engine flows can be immense but the prize for control substantial. For example, the leakage flows at the tip of a gas turbine blade and the cooling airflows in a combustion chamber contribute significantly to engine fuel burn and emissions respectively. Many such engine flows are high speed, high pressures (20bar+) and at high temperatures (500 degC+) and reside in difficult to access parts of the engine. This means that conventional valves and actuators that have moving parts are not viable due to inadequate life and slow response time.We shall consider here a novel concept of a valve that has no moving parts and works at the pressures and temperatures normally found in gas turbines or diesel engines. The Electro-fluidic-transistor-valves to be studied in this research use small plasma discharges in combination with fundamental fluidic effects to inject or switch off jets of air when commanded. One of the goals in this research is to understand the fundamental parameters that influence the operation and performance of such devices. How fast can such devices be made to operate? And how can control engineering be used to directly manipulate on the micro scale the flow past the turbine blade tip that is the single biggest contributor aero-engine inefficiency? To answer these questions, this ambitious proposal uses an integrated approach that will research the science of the plasma switched fluidic valves, identify the key control laws and architectures for high bandwidth flow control and then demonstrate the concept experimentally in a challenging high speed turbine application. This will require close research collaboration between control engineers and thermo-fluid specialists, a direction well aligned with EPSRC strategy for both Control Engineering and Aerodynamics disciplines. The applicants are convinced that this multi-channel approach is the best way to propel this potentially disruptive technology into CO2 saving applications.