Study on Relationship between Sound Wave and Temperature of Fault Diagnose of Liquid Transmission System

Among impacts on fault diagnosis accuracy of many factors, fluid temperature plays an important role on the physical and mechanical properties such as modulus of elasticity, viscosity, and so much, thus affects the transmission of sound wave velocity and attenuation. By analyzing the fluid stress and strain relations under heat, wave propagation equation of fluid under heat is derived to study the fluid nature of sound wave spread with temperature varied. Sound attenuation coefficient and sound speed analytical expressions are solved with the temperature stability of the state, and some conclusions are gotten with calculations of the above expressions: the leak frequency range of 0 to 5000 Hz has no effects on measurement precision of sound speed and attenuation; With temperature rising in the range of 0 to 30degC, the compressional wave velocity increases and the attenuation coefficient reduces; The effect of elastic modulus on the fluid acoustic properties is the largest in the state of temperature varied. Results of the study provide temperature compensation for fault diagnosis of fluid transmission pipeline system, so as to enhance the accuracy of diagnosis.