Research Of Area-aware Complex Impedance Ice Detection Technique

As one of the six major meteorological factors threatening flight safety,aircraft icing phenomenon has led to many crashes.Accurate determination of icing status can effectively reduce flight accidents caused by icing,and provide valuable reference information for antiicing systems.Traditional icing sensors can only accurately detect the icing status of sensitive surfaces,which is a single point detection.In order to achieve regional icing detection,this thesis researches the complex impedance icing detection technology and proposes an icing detection method based on impedance measurement array.Firstly,this thesis carries out the research on the principle of complex impedance type icing detection,analyzes the relationship between dielectric polarization mechanism and frequency,and obtains the change law of complex dielectric constant of ice/water with frequency.The electrode model is established using the electrical module of COMSOL Multiphysics to clarify the changes in response signal and sensitivity of electrodes with different structural parameters and the direction of parameter optimization when the ice thickness increases,and summarize the applicable scenarios of different electrode shapes.According to the research results,this thesis designed the impedance icing sensor to meet the requirements of the project,and conducted icing wind tunnel tests,and found that the response signal of the impedance icing sensor has the problems of temperature drift and difficult to measure the ice thickness during icing.The experimental results show that the measurement error of the ice condensation rate of this model is within 15%.Then,this thesis presents an in-depth study of the complex impedance-based icing detection technique based on relaxation polarization.The effect of temperature on ice dielectric constant is analyzed,and the ice temperature estimation and temperature drift selfcorrection model is established by combining the relationship between the relaxation frequency and temperature of ice.The experimental results show that the measurement error of inter-pole capacitance value decreases 77% compared with that before correction.The ice water dielectric constant variation law at different frequency points during the icing process is analyzed,and the interpole capacitance value is calibrated using the real ice condensation rate during the icing process,and the model of ice condensation rate measurement during the icing process is established by combining the simulation and experimental data.Finally,the icing detection method based on impedance measurement array is studied.An impedance array icing detection test platform is built to simulate the actual icing environment,and the ice thickness calibration is performed on the inter-pole capacitance values measured by the adjacent electrode pairs to achieve a single-point ice thickness measurement with a maximum deviation of 0.25 mm.By solving the ice thickness information collected from each adjacent electrode pair,the ice thickness of each adjacent electrode surface and the approximate ice thickness of the electrode interval are obtained,and the icing scenario on the electrode surface is reconstructed by this method,and the results show that the icing detection method based on the impedance measurement array can restore the ice thickness distribution on the electrode surface of the impedance measurement array more completely.