Study On Thermal-solid Coupling And Dynamic Characteristics Of Mechanical Seal For Pump

A mechanical seal is a device that achieves axial sealing under the dual effects of pre-tensioning of dynamic and static ring end face seal pairs and medium pressure by means of elastic elements.It is also called end face seal.According to the specific pressure of the end face,it can be divided into contact mechanical seal and non-contact mechanical seal.In the early days of mechanical seals,the material of the end face was single,and the wear amount and service life were short.With the continuous development of material science and the birth of new technologies,the application of new ceramics,alloys and coating materials on mechanical seals has made them wear less and have a longer life,Low energy consumption,low leakage,stable working conditions and strong adaptability,etc.,are widely used in aerospace,petrochemical,marine,auto motive and other fields.Data show that the application rate of mechanical seals in the petrochemical industry at home and abroad is as high as 80% or more.In the current research,the mechanical seal is generally stripped from the entire axial sealing system and subjected to steady-state analysis.Without considering the dynamic characteristics of the mechanical seal and the effect of equipment vibration on the sealing characteristics,the theoretical service life of the mechanical seal is higher than the actual service life,and the theoretical leakage is less than the actual leakage.This subject uses the Ansys Workbench simulation platform to analyze the mechanical properties of the friction pair of the contact mechanical seal under different materials and speeds;calculates the leakage and wear rate through fractal theory;The sealing friction pair and the overall structure of the mechanical seal are analyzed for structural dynamics to more accurately analyze the friction mechanism of the contact mechanical seal.(1)Ansys Workbench is used to analyze the thermo-mechanical coupling of the friction pair of the contact mechanical seal.When the speed is too fast,the thermal management stress of the contact surface of the friction pair will rise linearly,and it is free to know when the working state is not clear.Choosing the material of the friction pair will damage the material of the friction pair and cause leakage.(2)It can be known from the fractal theory that the contact mechanical seal has extremely low leakage and wear in the range of its fractal dimension D,but there is a large error from the actual measured value.(3)Through calculation by Ansys Workbench dynamic analysis module,it is found that at the resonance frequency of the friction pair,the actual rotary displacement of the contact mechanical seal per unit time is higher than the theoretical value,and the micro-convex body on the contact end surface will ag ravate the wear between the friction pairs.(4)Combining the rotor dynamics theory and the dynamic characteristics of the mechanical seal,the mechanical seal and the motor shaft are regarded as a single-disk bearing rotor system,and the unbalance response of the system is analyzed.The system will have a great axial displacement at the critical speed,resulting in mechanical seal failure,which is a new form of mechanical seal failure.In summary,it provides theoretical support for improving the service life of contact mechanical seals,reducing the wear rate and reducing the leakage rate,and has played a guiding role in the engineering practice of mechanical seals.