Session: 12-08: Film Cooling Under Engine Like Conditions

Paper Number: 152615

Development of Two-Color Pyrometer for Film Cooling and Transpiration Cooling at High Temperature Conditions 

This study experimentally investigated transpiration cooling and film cooling on a flat-plate model. The aim was to use non-invasive two-color pyrometry for temperature measurement on the cooled surface. Unlike typical infrared thermography, this technique is not affected by changes in emissivity due to heating. An industrial camera captured light intensity through interference filters of different wavelengths, enabling calculation of the target surface's temperature and emissivity. Post-processing was conducted to visualize the results. Calibration coefficients were obtained using a blackbody furnace during the experiment, allowing comparison of surface temperature and emissivity results with those from thermocouples.

The test was carried out in a high-temperature wind tunnel capable of reaching a mainstream temperature of 1000°C. The target surface temperature during the test varied from 375°C to 600°C. High-temperature airflow was utilized to heat the specimens, and Two Color Pyrometry theory was employed to correlate signal intensity at wavelengths of 1250 nm and 1550 nm with temperature. The test specimens, measuring 60mm × 65mm × 4mm, featured various transpiration cooling and film cooling structures. These flat-plate cooling samples were made from three different materials: Ti-6Al-4V, AISI-316L, and Inconel-718. For transpiration cooling, unit structures were stacked to create a volume of 60mm×65mm×4mm; for film cooling, wider hole spacings were used. Measurements were taken to assess both the cooling effectiveness and surface emissivity. This method can be applied to gas turbine blades equipped with film or transpiration cooling systems.

 Keywords: Temperature measurement, Thermal imaging, High temperature wind tunnel, Two color pyrometry, Film cooling, Transpiration cooling

Presenting Author: Bo-Wei Chen Department of Mechanical Engineering, National Yang Ming Chiao Tung University

Presenting Author Biography: Bo-Wei Chen is currently a Ph.D student in the Department of Mechanical Engineering National Yang Ming Chiao Tung University. Their primary research interests lie in heat transfer and thermo-structural design. They have developed a strong foundation in both theoretical and practical aspects of thermal engineering]. Bo-Wei Chen is actively involved in two-color pyrometer, aiming to advance the understanding and application of thermo-structural analysis and development of non-intrusive temperature measurement.

Authors:

Bo-Wei Chen Department of Mechanical Engineering, National Yang Ming Chiao Tung University
Jing-Fa Chang Department of Mechanical Engineering, National Yang Ming Chiao Tung University
Szu-Chi Huang Department of Mechanical Engineering, National Yang Ming Chiao Tung University
Shih-Hsun Chen Department of Mechanical Engineering, National Yang Ming Chiao Tung University
Yao-Hsien Liu Department of Mechanical Engineering, National Yang Ming Chiao Tung University