冷效试验中涡轮叶片表面薄膜热电偶测温技术研究
摘要
<p indent="0mm">The structure of air-cooled turbine blades is complicated, and the interaction of high-temperature, high-speed gas, and cooling gas results in extremely uneven surface temperature distribution of the blades. The cooling effect test is the main method for checking the strengths and weaknesses of the cooling effect design of air-cooled turbine blades and also provides essential design data to avoid blade overtemperature. In the cooling effect test, real temperature measurement of the turbine blade surface becomes the key. Thin-film thermocouples (TFTCs) are tightly attached to the surface of the object undergoing the test. They are only a few microns thick and can be used to accurately and quickly obtain the surface temperature information of turbine blades. It is an urgently required key technology in the field of high-temperature testing of aero engines, while our country has not yet been using it in engineering applications. Herein, turbine blade test samples with Pt–Ir TFTCs are prepared on the basis of research on simple, noble-metal TFTCs. The calibration results demonstrate that the TFTCs exhibit remarkable stability and accuracy in temperature measurement. A cooling effect test is performed in an environment of high-temperature, high-pressure flow field, and the temperature data of the entire process of the test are obtained. The overall trend of the temperature measurement data of the TFTCs is observed to be consistent with the ambient temperature. The temperature measurement data of the TFTCs show that the surface temperature of turbine blades is notably different from that in the very near space, and the closer to the surface of the turbine blades, the temperature the lower. In addition, the temperature distribution on the surface of the turbine blades is not uniform. As per the distance from the cooling holes, the temperature near the trailing edge is higher than that near the cooling holes. The temperature is mainly affected by gas tempera