The Numerical Analysis And Experimental Study Of Thermal Characteristics Of Structure For Side-entry Single Mechanical Seals

Side-entry agitator mechanical seal is a key part of FGD absorber stirring and mixing system which is widely used in heat-engine plant.Because the stirrer is mounted horizontally and its longer cantilever,the small axial displacement of spring caused by shaft vibration will form axial variable loads during operation,which makes local higher temperature and stress easily exist on the end faces.It further induces thermal cracking and serious abrasion,which directly causes seal failure and decreases the overall performance of stirring device in a large scale.Therefore,carrying out the side-entry agitator mechanical seal's characteristic research has important practical engineering and theoretical value to deepen analyze the reason of seal failure.Focusing on the mechanical seals for side-entry agitator,considering the coupling effect of thermal and mechanical deformation,the fluid film thickness of end face and the viscositytemperature characteristics of the fluid film,an axial symmetry theoretical finite element model was established,carrying out the steady-state thermal coupling characteristics of the sealing ring,transient coupling effects on the condition of alternate spring force,and verified by several experiments.Firstly,taking the coupling relationship of the thermal and mechanical deformation of sealing rings,the fluid film thickness into consideration,an axial symmetry calculation model was established,using overall contact coupling method and simplified Reynolds equation.Solving the fluid film,contact pressure distribution and the end face temperature,analyzing the sealing performance under different conditions further.The analyzed results show that the minimum film thickness is close to the external diameter of the sealing rings,which has the highest temperature and contact pressure.The leakage rate,friction torque and temperature rise became larger with the sealing pressure and rotation speed increasing.Secondly,taking the alternative spring force as the subject of investigation,studying the sealing performance under alternate load,the results indicate that the seal and faces characteristics such as contact pressure and face temperature are also alternate and transient under alternate load conditions.Finally,the temperature under different operating conditions were studied by K type temperature sensors mounted on different locations of stator ring,The analyzed results show that minor changes of temperature will occur in the moment and dynamic load of stirring,it will be a sharp increase in the start-up and will fluctuate alternately during stable operation.Some parameters such as friction torque,face temperature were tested on the test platform independently designed for the side-entry agitator mechanical seal instrument.The experiment data is in good agreement with the theoretical calculating results,which verify the theoretical analysis.