Heat Transfer > Infrared Imaging
Mid-Wave IR Thermal Imaging for Combustors
The combustor is at the highest temperature and pressure of the gas turbine, and has a complex flow field as can be seen in the left image below. If there is a design flaw or a prediction problem, a major accident can occur, as can be seen in the image on the right. To avoid this, it is important to know the internal surface temperature field of the combustor. However, it is difficult to measure the surface temperature in this high temperature and pressure environment. Our team plans on performing these temperature measurements on the inner surface of gas turbine combustors in a non-destructive manner. This will help determine the accuracy of analytical predictions, check design quality, and identify hot spots.
A thermal camera is a device that measures temperature using infrared (IR) rays emitted by an object. It is not necessary to install something inside the gas turbine, but it is necessary to make a view port through the outer casing and on the combustor liner, and install an optical tube to collect the IR light. Interference from the flame and combustion products such as CO2 and H2O can be removed with a spectral filter, and the surface temperature field can be measured directly, as shown in the burner image below. A mid-wave IR camera will be used to image the inner surface of a combustor, a sample of which is shown in the image below.
Short-Wave IR Thermal Imaging for the Turbine
The rotating turbine blades must be actively cooled through methods such as film cooling, because the hot exhaust gas from the combustor flows over them. By observing the thermal state of these turbine blades in real time, it is possible to identify and cope with various problems in the high pressure turbine. A short-wave IR camera can be used to obtain real-time, non-destructive measurements of the surface temperature of the rotating turbine blades under actual operating conditions. This helps to identify problems such as TBC spallation, cooling hole blockages, platform gap leakage, and film cooling deficiencies.
