Study On Expansion Coefficient And Performance Of Conductive Fluid In MHD Micro-Angle Vibration Sensor

With the development of aerospace technology,the role of high-precision spacecraft is becoming more and more prominent,and it is widely used in military reconnaissance,laser communication and earth mapping.When the spacecraft is disturbed,it will vibrate slightly,which seriously affects the attitude and the stability of the visual axis.Therefore,effective measurement and control are required.Magnetohydrodynamic(MHD)micro-angle vibration sensor has the advantages of high bandwidth,low noise and small size,making it the best choice for detecting highfrequency micro-angle vibration in high-precision spacecraft.At present,domestic research on MHD micro-angle vibration sensors mainly focuses on structural design,noise analysis and low-frequency expansion,etc.There are few studies on the influence of conductive fluid characteristics on sensor performance.Therefore,we need to improve the parameters of the conductive fluid,such as volume expansion coefficient,gas solubility,etc.,and analyze the impact of various parameters on the output characteristics of the sensor to provide theoretical support for the optimal design of the sensor.In this paper,for the current conductive fluid materials used in MHD micro-angle vibration sensors,the following research is done from the volume expansion coefficient and its effect on the sensor output characteristics:1.According to the working principle of the MHD micro-angle vibration sensor,the influence of the volume expansion coefficient of the conductive fluid on the output potential of the sensor is analyzed,and a theoretical mathematical model is derived.Based on the structural design of the sensor and the characteristics of the conductive fluid,Fluent software was used to simulate and analyze the effect of the volume expansion coefficient at different temperatures on the output potential of the sensor.The curve of the induced potential with the volume expansion coefficient was quantified.2.Analyzed the advantages and disadvantages of the commonly used methods for measuring the volume expansion coefficient of fluids.In view of the characteristics of conductive fluids,a method for measuring the volume expansion coefficient of conductive fluids based on anaerobic static weighing method was innovatively proposed(patent has been declared)Theoretical mathematical model.3.Designed the overall scheme of the measurement system of the volume expansion coefficient of the conductive fluid,built a measuring device with adjustable temperature,and used LabVIEW and Python programming language to write the data acquisition and processing program.The accuracy of the measurement system was verified by using distilled water with known volume expansion coefficient.On this basis,the volume expansion coefficient of the conductive fluid was measured to achieve a more accurate measurement.Combined with theoretical simulation,the conclusion that the influence of the expansion coefficient of the conductive fluid measured under the experimental conditions on the output potential of the sensor is 0.0556% provides a theoretical basis for the subsequent optimization of sensor design.