Numerical Simulation And Optimization Design Of Limit Current Type Oxygen Sensor

In precision aerospace instruments,as a kind of sensor to detect the concentration of oxygen in the atmosphere,oxygen sensors play an irreplaceable role.As the core component of oxygen meter,the plate-type limit current oxygen sensor has become the focus of research and development due to its fast response,high sensitivity,good stability,long working life and the advantage of no reference gas.In this paper,numerical simulation and experimental verification methods are combined to carry out the mechanism of oxygen sensor structure size and working conditions on the performance of the mechanism,and for different ranges,different working conditions of the sensor structure size,response time,output performance indicators,thermodynamic properties were modeled,characterized and coupled with performance optimization.First,the working mechanism and output characteristics of the limiting current oxygen sensor are analyzed.The gas diffusion mechanism of the limit current oxygen sensor,the reaction mechanism of the solid electrolyte oxygen pump and the production mechanism of the limit current are analyzed,and then Then the key factors affecting the output characteristics of oxygen sensors are extracted,for example,material characteristics,working environment,sensor structure size.By analyzing the structure of the sensor and analyzing the performance of the oxygen sensor,a limit current oxygen sensor for spacecraft environment is designed.Secondly,by using the methods of fluid dynamics and structural thermodynamics simulation,the complex working processes of multi-field coupling such as sensor physical diffusion,electrochemical oxygen pump reaction,temperature field and stress field are simulated and analyzed.By establishing the electrochemical and structural thermodynamic model of oxygen sensor,the multi-field coupling analysis based on component diffusion,porous media transmission,electrochemical-thermal coupling and electro-thermo-mechanical coupling is carried out.Through these analyzes,the size of the diffusion hole and the thickness of the microchannel that satisfies the shortest sensor response time are obtained.The relationship between the heating voltage and the temperature of the oxygen sensor is obtained through the analysis of the heating characteristics of the oxygen sensor,the cold start response time,temperature field,thermal stress and total deformation of the oxygen sensorare analyzed.Two kinds of solid electrolyte materials are compared and analyzed,and the cause of thermal stress is analyzed from the angle of thermal expansion coefficient.Finally,based on the steady-state thermo-mechanical coupling analysis,the multiobjective optimal design of the sensor size and the shape of the heating chip is carried out with the objective function of sensor temperature,stress and deformation.The oxygen sensor is prepared and the overall performance is tested by the optimized design structure.The optimization design method of numerical simulation is verified by the output characteristic,response time and temperature rise characteristic,and the error is analyzed.Finally,an optimized design structure of oxygen sensor that meets the aerospace requirements and has a working range of 0.01-96%,wide range,high precision,long service life,fast response and low power consumption is given.In this paper,a combination of numerical simulation and experimental verification is used to analyze and optimize the factors that affect the performance of the sensor.A fast and reliable structure design and optimization method for oxygen sensors can be given in a specific environment.