Research On Frictional Wear Mechanism And Leakage Characteristics Of High-Speed High-Temperature Mechanical Seals With Cr-Cnts Coating

With the increasingly harsh working parameters in the chemical,aviation and nuclear power fields,the long-term stable operation of high-speed high-temperature mechanical seal faces is the key to ensure the normal operation of the equipment.The use of composite coating to strengthen the seal face is an effective way to improve the reliability of high-speed high-temperature mechanical seals and extend the service life of the equipment.This paper uses a combination of numerical simulation and experimental analysis to explore the frictional wear mechanism of high-speed high-temperature mechanical seal Cr-CNTs coating end face,analyze the temperature rise and deformation law of the seal end face,and predict the leakage of the seal end face.It provides research methods and research ideas for improving the performance of high-speed high-temperature mechanical seals.The paper uses laser coating method to prepare different coating seal end faces,and the friction and wear performance of seal end faces without coating(38Cr Mo Al A),Cr coating and Cr-CNTs coating are compared under different working conditions,and the effects of coating thickness and carbon nanotube content on the hardness,self-lubrication and wear resistance of end faces are analyzed to investigate the friction and wear mechanism.The results show that the appropriate amount of carbon nanotubes within the coating can improve the preparation quality of the coating.The wear resistance of seal end face increased by 19.5%,and the friction coefficient decreased by 12.5%.The presence of carbon nanotubes on the coating surface provides excellent wear reduction properties in the form of rolling and film formation.However,the excessive amount of carbon nanotubes will lead to the generation of pores during the preparation of the coating and affect the preparation quality.The increase in coating thickness resulted in enhanced end face wear resistance,increased efficiency and uniformity of graphite transfer film generation,and reduced friction coefficient with an optimum coating thickness of 0.15 mm.The paper adopts the finite element calculation method and establishes the thermal-solid coupling numerical model to study the influencing factors and change laws of temperature rise and deformation of Cr-CNTs coating end face.The leakage channel model and end face contact model are established,and the leakage rate calculation method of the seal end face is proposed to analyze the leakage law of Cr-CNTs coating end face under different working conditions.The results show that the seal end face produces dispersion-type deformation under high-speed and high-temperature conditions.The appropriate increase of the coating thickness can help to reduce the temperature rise and deformation of the end face and improve the stability of the seal end face.The Cr-CNTs coating can effectively reduce the end face temperature rise and deformation,and reduce the leakage rate.A high-speed high-temperature mechanical seal test rig was built to compare the temperature rise,wear and leakage rate of seal end faces without coating,Cr coating and Cr-CNTs coating.The test results show that the Cr-CNTs coating can reduce the temperature rise rate of the seal face and improve the stability of the seal face.The experiments verified the correctness of the seal end face analysis model and leakage rate model calculation results.The optimal CNTs content of Cr-CNTs coating for high-speed high-temperature mechanical seal is 10% and thickness is 0.15 mm.In this paper,through numerical analysis and experimental study of Cr-CNTs coating seal end face,the influence of CNTs content and coating thickness on end face performance is investigated,the frictional wear mechanism of Cr-CNTs coating seal end face is revealed,and the calculation method of seal end face leakage rate is proposed.It can provide an important reference for the industrial application of high-speed high-temperature mechanical seals,and provide theoretical guidance for optimizing the seal structure,improving the seal working conditions and enhancing the seal life.