Thermal Imaging for Effusion Cooling

Modern gas turbine combustors use effusion cooling to cool the combustor walls.

The effectivness of the effusion cooling plates can be assessed by studying the temperature field on the plate. Conventional measurement techniques such as thermocouples are intrusive and only give data at discrete points. An alternative is to use an infrared thermal imaging camera to view the temperature field on the plate. Thermal imaging can greatly enhance the study of effusion cooling as it gives a continuous temperature field, is non intrusive, and has a high degree of accuracy and resolution.

Recent technological advancements in uncooled thermal imagers have allowed the use of low-cost infrared cameras in applications previously limited to research-grade cameras.

The objective of this research is to assess the utility of a low-cost, uncooled, infrared camera in effusion cooling research for gas turbine combustors.

To validate the technique, thermal images of a flat plate downstream of two cylindrical hot jets in cold cross-flow were compared to thermocouple readings. Results showed that the technique had a spatial resolution of 0.4mm, and a temperature sensitivity of 0.1°C. The system compared favorably with established infrared measurement systems.

Temperature contours down stream of effusion cooling hole measured using thermal imaging.