Sensors: Temperature and Heat Flux Sensor for Gas Turbine Coatings

该提案是根据传感器和传感器网络征集（NSF 04-522，分类为个人研究者提案）收到的。今天的社会依靠燃气涡轮发动机发电和飞机推进。为了提高整体能源效率并最大限度地减少维护，需要开发新的涂层、传感器和控制装置。我们的研究重点是高温热障涂层，它为涡轮叶片和燃烧室提供隔热，使发动机在更高的温度下运行，因此比未涂层的发动机效率更高。具体来说，我们正在开发一种全光传感器，用于原位测量温度和热障涂层的热流密度，以及“健康监测”和设计验证以及可靠性和寿命预测的关键传热参数。由于涂层的寿命，金属叶片和叶片都取决于它们的最高温度，与金属直接接触的内涂层表面的温度是一个至关重要但目前尚不清楚的参数。同样，涂层外表面的实际温度，与表面的气体温度不同，也会影响涂层的寿命和耐久性。通过测量涂层厚度上的温差，可以确定热流密度。我们提出的传感器的基础是不同稀土掺杂剂的特征温度依赖性发光，我们将其纳入现有热障涂层材料的晶体结构中。通过在涂层中不同层次放置掺杂剂，它成为一个结构化传感器，其信号来自涂层中掺杂剂所在的位置，例如在内表面和外表面。虽然重点是热障涂层的温度测量，但方法、选择用于高温发光的掺杂剂的协议和整体传感器设计考虑预计对其他重要的材料高温测量应用有价值，特别是在光学高温计不可用或被热辐射掩盖的材料结构中。该计划的一个组成部分是，研究生将在美国宇航局格伦研究中心使用激光驱动的高热流测试平台对传感器进行测试，使他们能够体验不同的工作环境，并向研究专业人员和合作者学习。该提案由化学和运输系统部的热传输和热处理项目以及民用和机械系统部的民用和机械系统传感器项目资助。

This proposal was received in response to the Sensors and Sensor Networks Solicitation, NSF 04-522, category Individual Investigator Proposals.Society today relies on gas turbine engines for both the generation of electricity and aircraft propulsion. To increase the overall energy efficiency as well as minimize maintenance, there is a drive to develop new coatings, sensors and controls. The focus of our research is on high-temperature thermal barrier coatings that provide thermal insulation to the turbine blades and combustion chambers allowing engines to be operated at higher temperatures, and hence higher efficiency, than uncoated engines. Specifically, we are developing an all-optical sensor for in-situ measurement of the temperature, and heat flux, across thermal barrier coatings, crucial heat transfer parameters for both "health monitoring" and design validation as well as reliability and life prediction. As the life of the coating, the metal blades and vanes all depend on their maximum temperature, the temperature of the inner coating surface, which is in direct contact with the metal, is a vital but presently unknowable parameter. Likewise, the actual temperature of the coatings' outer surface, as distinct from the gas temperature at the surface, also affects coating life and durability. With measurements of the temperature difference across the thickness of the coating the heat flux can be determined.The basis of our proposed sensor is the characteristic temperature-dependent luminescence from different rare-earth dopants that we incorporate within the crystal structure of existing thermal barrier coating materials. By placing the dopants at different levels in the coating it becomes a structured sensor whose signals come from the positions within the coating where the dopants are located, for instance at the inner and outer surfaces. Although the focus is on temperature measurement in thermal barrier coatings, the methodology, the protocols for selecting of dopants for high-temperature luminescence and the overall sensor design considerations are expected to be of value for other applications where it is important to measure high temperatures of materials and, in particular within structures of materials where optical pyrometer is not feasible or masked by thermal radiation.An integral part of the program is that the graduate students will perform tests of the sensors at NASA Glenn Research Center using the laser-driven high heat flux test rig there, enabling them to also experience a different working environment and learning from research professionals and collaborators.The proposal is being funded by the Thermal Transport and Thermal Processing Program of the Chemical and Transport Systems Division and the Sensors in Civil and Mechanical Systems Program in the Civil and Mechanical Systems Division.