Speaker
Description
Cyclic fatigue is an important effect responsible for the service life of gas turbine engine blades. One of the implementations of the destructive effect is the thermoelastic effect that occurs in the blade material when the engine operation changes. In this case, a superposition of the heating field from the gas-plasma flow from the outside of the blade and the forced cooling field from the air flow directed through the internal channels of the blade blade occurs. It is the imperfections of the surface of the cooling channels that cause premature failure. To detect imperfections inside the cooling channels, a test stand was developed, which consisted of a Fluke 32 thermographic camera, a compressor for cooling the blades through the internal channels and various heating sources (electrothermal, thermal hair dryers, an ultrasound source). The study involved obtaining thermograms on the blade surface when it was heated by a reference wire placed in the cooling channels as a source of Joule heat. Thermograms were obtained in the mode of internal cooling - external heating with a heat dryer. Testing was carried out in the mode of heating with an ultrasound source. Estimates of the temperature increase at different frequencies of applied cyclic influences were made. The method of image clustering and methods of statistical processing of temperature field gradients were used to process thermographic data. The prospects of using thermographic test control for objects operated under conditions of vibration and cyclic temperature loading are shown.
