Temperature Stability Analysis Of Sensitivity Of Circular Tube Hydrophone And Research On Calibration Technology

With the development of underwater acoustic detection technology,the detection environment that the underwater acoustic detection system faces is becoming more and more complex.As an important part of the detection system,the hydrophone is also faced with a complex and changeable detection environment,so its measurement accuracy will also be restricted by various aspects.As an important factor affecting the performance of hydrophones,temperature has always attracted much attention,and the temperature stability of hydrophone sensitivity is also the focus of attention in the field of underwater acoustics.In this paper,a system for calibrating the sensitivity of hydrophones under variable temperature conditions is built.Firstly,the distribution parameter model of the infrasound field in the ideal cavity is established,and the expression of the sound pressure sensitivity of the hydrophone calibrated by the standing wave tube method is deduced.By using COMSOL simulation technology and theoretical calculation to analyze the influence of the inner diameter and wall thickness of the non-rigid pipe on the uniformity and purity of the sound field,the size of the calibration pipe was determined.The heating and heat preservation part of the temperature-variable calibration system and the jig that can move in six dimensions are designed.After that,the performance of the system is studied,and the reliability of the system is determined through the inspection of the system,and the extended uncertainty of the calibration is1.0 d B(k=2).The main influencing factors of the hydrophone are obtained through the static receiving theory of the sensitivity of the circular tube hydrophone,and the changes of these influencing factors with temperature are actually measured.The theoretical analysis of temperature change,by comparing with the measurement results of the hydrophone sensitivity calibration system in the variable temperature environment,explains the reason why the temperature affects the hydrophone and the reason why the theory and practice are different.The research of the thesis shows that the sensitivity of hydrophone is negatively correlated with temperature,and the capacitance of hydrophone is positively correlated with temperature,which is consistent with the theoretical analysis;The difference between the theoretical value and the actual measured value is mainly caused by the thermal expansion characteristics of the hydrophone surface coating material itself and the temperature characteristics of the acoustic impedance.