Research On Performance Of Speed Controllable Middle Ring Mechanical Seal Of Electro-magnetic Drive

As a new seal, dry gas seals can achieve low power consumption,long life comparedwith other type seals.Now the dry gas seals have been successfully used in high speed turbocompressors,however,the application with dry gas seals on mixer and agitator has somedifficulties such as hard to open and large amount of the shaft runout.Therefore it’s veryimportant to analysis the sealing performance in low speed and low pressure condition anddesign the structure of dry gas seal reasonable.Based on a type of middle-rotating-ring mechanical seal device that has been grantedpatent in China (No. CN201020155964.0), this paper put forward a new middle-rotating-ringdrive mode called ‘permanent magnetic drive’, which is then used to improve its structuredesign. Through the analysis of traditional drive modes, it is the rare earth permanentmagnetic drive that finally be chosen as the most suitable middle-rotating-ring drive mode,followed by design of the massive structure of the driving mechanism as well as theinstallation. In discussing the rationale behind seal in middle-rotating-ring permanentmagnetic drive, the paper also research on issues that might arise in this specific device. Inaddition, the calculation for the main ratings and dimensions towards middle-rotating-ringdrive mode under certain conditions has been completed, which lays foundation for thefurther improvement of middle-ring seal.Through the brief introduction of hydromechanics as well as its basic research methods,the decision has been made to CFD, which is the most widely used research method inmodern hydromechanics. Based on the fundamental theory of hydromechanics, this paperanalyzes on the basic equations of middle-ring helical groove gas dry seal thickness of fluidfilm and chooses the most suitable calculation method. Based on the features ofmiddle-rotating-ring mechanical seal, this paper takes advantage of Fluent (a applicationsoftware of CFD) and establishes a three-dimensional mathematical model within the flowfield of middle-ring helical groove dry gas seal. With the help of simulation analysis, thismathematical model explores effects of film thickness, rotation speed and pressure at outsidediameter that would have on the function of middle-ring seal as well as pressure distributionin a fluid film. In addition to the analysis of rationale behind the seal in the controllable electromagneticdrive middle-ring rotation speed mechanical seal, this paper focuses on the calculation anddesign of middle-ring drive mode. Furthermore, the distribution capacity as well as thevariation of leakage rate under variable parameters and thickness of fluid film has also beenconsidered for the purpose of further research.