Steady Character Research And Software Development Of Liquid Film Seal With Herringbone Grooves

The herringbone grooves liquid film seal is a non-contact mechanical seal with herringbone grooves curved on the end face of seal ring.Especially,the herringbone grooves liquid film seal with double-loop belt not only guarantees little leakage even zero leakage of process medium,but also ensures sealing faces fit tightly and closely when rotating machines shut down.In the researches of liquid film seal,the influence of cavitation effect was usually ignored,and the two-way coupling effects among flow field,temperature field and deformation were usually not considered.Difference can be found between result and actual suitation,so a further study on the herringbone grooves liquid film seal is necessary.At the beginning of this paper,a math model of pressure distribution of double-loop belt herringbone grooves seal was established,based on the Reynolds cavitation model.A math model of temperature distribution of seal ring and mechanical/ thermal deformation was established,based on the energy conservation equation.The equation is discreted by using the finite difference method,and the successive-over-relaxation method for iterative solution.The flow field parameters of liquid seal,the temperature distribution and mechanical/ thermal deformation of seal ring are calculated by using Matlab programming,comparing with the results of Fluent and Ansys Workbench simulation.Then,a heat-fluid-solid bi-directional coupled model between seal rings and liquid film was established with the application of Matlab,which can obtain significant performance parameters of the seal in steady state: liquid film stiffness,leakage,the highest temperature and the taper of deformation.Effects of structural parameters of the end face on sealing performance are studied in order to optimize the structure of sealing end face.At last,The software for sealing performance analysis is developed by applying Matlab GUI.It can be implemented on the analysis of the heat-fluid-solid bi-directional coupled,including a variety of trough-type liquid film seal.Meanwhile,a useful analysis tool for the personnel engaging in mechanical sealing design is provided.Results of calculating sealing gap flow field indicate that high pressure zone appears at the fork of the herringbone grooves,while the low pressure zone appears at the groove root of inner/outer diameter.When speed reaches a certain value,cavitation could be observed on the liquid film.There are some gaps among the leakage,friction torque and liquid film stiffness in two kinds of calculation methods.Therefore,a reasonable calculating method should be selected on the basis of the working condition parameters.Expansibility in cavitation region have been found in this paper.Results of calculating temperature and deformation of seal ring indicate that the temperature of ring increases with the increasing speed,and the total deformation is dominated by heat deformation.The taper of thermal and mechanical deformation is in the opposite direction,and mechanical deformation partially offsets the thermal deformation.The herringbone grooves seal with double-loop belt performs better with parameters showed in the paper: ratio of ridge width to groove width takes 1 to 1.5,helix angle should be from 22o to 26o,groove depth should be from20?m to 35?m,and the number of groove is from 36 to 48.