The Optimization Design Of Multiplex Sensor Used For Aero-engine Gas Path Detection System

Aviation security has always been a prerequisite to develop the aircraft industry, because accidents, when occurred, will result in heavy casualties and property losses. The complex structure and bad working condition of the aircraft engine becomes one of the major causes of failure, putting forward relatively high requirements to the depth and real-time performance of the aviation engine fault detection technology. Considering the characteristics of the aircraft engine gas path structure, a multiplex sensor is designed for aircraft engine gas path detection by combining two different sensors in this paper, one is the electrodynamic sensor designed based on the principle of electrostatic induction, and the other is a capacitance sensor developed based on the principle of electrical capacitance tomography(ECT). Both of the sensors act through the electric field, due to the ‘soft field' property of the sensitive field and the interaction of the two sensors, optimization of the parameters of the sensor structure are required, the main contributions are as follows:First, a 16-electrode ECT sensor is simulated, the characteristics of the ECT sensitive field are analyzed, and the optimization indices of the ECT sensor are defined, including uniformity index and sensitivity index. Thereafter, the structure parameters of the ECT sensor such as the length of the electrodes and thickness of the insulating layer are optimized by using the large-scale finite element analysis software ANSYS.Second, a 4-probe electrodynamic sensor is designed for the exhaust nozzle pipe with big diameter. Simulations are conducted for the designed electrodynamic sensor, optimization paths in the sensitivity are chosen and optimization indices of the sensor are defined,including uniformity index and mean sensitivity value index of the sensitive field. Finally, the length and width of the probes, the permittivity and thickness of the insulating layer are optimized.Third, based on the optimization of ECT sensor and electrodynamic sensor, the multiplex sensor is designed by coupling the 4 electrodynamic sensor probes and the 16 ECT electrodes.ANSYS is utilized to simulate the sensitivity field of the multiplex sensor, the interaction between the two sensors is analyzed and the geometric parameters of the multiplex sensor structure are optimized.At last, the ANSYS parameterized programming language(APDL) is utilized to develop the simulation and optimization program for the electrodynamic sensor, ECT sensor andmultiplex sensor, as well as the corresponding interface, which provides a platform for further research on the multiplex sensor.