Study On Flow Field Characteristics And Self-Cleaning Property Of Spiral Grooved Upstream Pumping Liquid Film Seals

With the development of modern industries such as fine chemicals,metallurgical industry,sewage treatment,etc.,the operating environment of the spiral grooved upstream pumping mechanical seal tends to be more than that of solid particles.The case of sealing failure caused by blockage of the pumping groove and wear of the sealing end face is not uncommon.In order to explore the feasibility and technology of using the sealing end face geometry groove to prevent particle deposition,this paper develops the study on flow field characteristics and self-cleaning property of spiral grooved upstream pumping liquid film seals.Firstly,based on the FLUENT software and fluid dynamic pressure lubrication theory,the flow field characteristics of the spiral groove sealing micro-gap liquid film are taken as the research object,and the geometric model of the numerical analysis of the particle motion in the liquid film is established.Meanwhile,the boundary conditions and meshing methods of the analysis object is determined,and the accuracy of the calculation method is verified.Secondly,for the sharp-angled,rounded spiral groove geometry structure,the scouring characteristics and improved design of the spiral grooved upstream pumping flow field are carried out.The results show that the rounded structure can produce strong eddy current,and the average vorticity near the root of the groove increases first and then decreases with the increase of the radius of the fillet.When the radius r=0.3 mm,the average vorticity reached the maximum;when the rotating speed is constant and fillet radius r=0.3 mm,the average vorticity near the groove root increases first and then decreases with the increase of the groove depth.Until the groove depth h_d=6?m,the vorticity value reaches the maximum,but does not change significantly with the helix angle and the ratio of the groove to the diameter.Then,the design of the seal test bench with solid particle working condition was carried out.According to the material characteristics of the sealing ring,appropriate moving ring,static ring,auxiliary seal and elastic component under this condition are selected.At the same time,the experimental steps and the data required for the experiment are listed to ensure the smooth progress of the experiment and the data difference analysis of the experimental results.Finally,the self-cleaning experiment of the spiral grooved upstream pumping liquid film seals with particles was carried out.Through the changes of the surface roughness and the mass wear rate of the seal ring,the properties about excluding particle of seal faces were compared and analyzed.The results show that the sharp-angled groove root structure has a serious accumulation of particles,a small amount of particles enter the interstitial liquid film to cause abrasive wear on the seal ring,and the roughness change is small,but the wear rate of graphite ring is large,almost 0.1002 mg/h;The rounded groove root structure has strong ability to exclude particles,and the particles are mostly distributed between the sealing rings,therefore,the surface roughness of the seal ring changes greatly,but the wear rate of graphite ring is small,only 0.0402 mg/h.Through numerical simulation and experimental research,the variation of the local flow field under the sharp-angled and the rounded structure,the particle deposition of pumping groove and seal face wear are obtained.The experiment verified the feasibility of self-cleaning design of spiral grooved upstream pumping liquid film seals with particles,and It has certain practical engineering significance for improving stability and reliability of seals in the medium containing particles.