System and method for defect detection of thermal barrier coating system in confined space based on flexible internal-external integrated excitation sensing

A system for defect detection of a thermal barrier coating system in a confined space based on flexible internal-external integrated excitation sensing, comprising:

• a flexible probe applicable to detection of a curved structure of a blade in the confined space;
• and
• an internal-external integrated excitation sensing device;
• wherein the flexible probe comprises a dual-layer meander-type flexible excitation coil, a flexible electromagnetic detection coil array, a thermal insulation aerogel and a patch-type flexible electronic-ionic temperature sensor array;
• the flexible electromagnetic detection coil array is arranged on the dual-layer meander-type flexible excitation coil;
• the thermal insulation aerogel is arranged between the flexible electromagnetic detection coil array and the patch-type flexible electronic-ionic temperature sensor array to eliminate influences of heat generation from internal and external heat sources;
• the internal-external integrated excitation sensing device comprises a temperature acquisition unit, a control-storage unit, a time-series control unit, a current source excitation unit and an electromagnetic signal acquisition unit;
• the control-storage unit is connected to the temperature acquisition unit, the time-series control unit and the electromagnetic signal acquisition unit;
• the time-series control unit is connected to the current source excitation unit to control the current source excitation unit to output excitation currents with different phases;
• the dual-layer meander-type flexible excitation coil, the flexible electromagnetic detection coil array and the thermal insulation aerogel are integrated on a circuit to be connected to the current source excitation unit and the electromagnetic signal acquisition unit;
• the patch-type flexible electronic-ionic temperature sensor array is connected to the temperature acquisition unit;
• the internal-external integrated excitation sensing device is configured to set excitation current amplitude, frequency, phase and excitation time via the control-storage unit, and to generate a trigger signal;
• the control-storage unit is configured to synchronously trigger the temperature acquisition unit, the time-series control unit and the electromagnetic signal acquisition unit;
• the time-series control unit is configured to receive the trigger signal to control the current source excitation unit to release an excitation, and output the excitation currents with different phases into the dual-layer meander-type flexible excitation coil of the flexible probe;
• the dual-layer meander-type flexible excitation coil is configured to generate an alternating magnetic field in a free space under current excitation to induce an eddy current within a metal substrate of the blade, and the eddy current within the metal substrate of the blade is configured to generate an internal Joule heat source;
• and the dual-layer meander-type flexible excitation coil has an inherent resistance, and the excitation current is configured to pass through the dual-layer meander-type flexible excitation coil to produce an external Joule heat source;
• and
• the external Joule heat source in the dual-layer meander-type flexible excitation coil is configured to be transferred into a thermal barrier coating system of the blade by heat conduction to collaboratively form a thermal excitation with the internal Joule heat source.