application of water vapor excitation in the non-destructive evaluation of gas turbine blades by active thermography

Thermography is one of the growing non-destructive testing (ndt) methods, which is used in various fields and industries such as energy audit, inspection of rotary machines, aerospace, oil and gas industries. recently application of thermography by incorporation of external energy source which is called active thermography has been developed to detect various defects such as cracks, delamination and moisture. in this study non-destructive testing of a gas turbine blade by active thermography was investigated. water vapor was used as external energy source. experimental tests are accomplished in three different pressures. thermal images were obtained in five equal time intervals. results showed good capability of this method in detection of ceramic-residual defect.