The coupling effect among the flow of fluid film, the frictional heat of fluid film and the thermal deformation of sealing rings is inherent in mechanical seals. The frictional heat transfer analysis was carded out to...The coupling effect among the flow of fluid film, the frictional heat of fluid film and the thermal deformation of sealing rings is inherent in mechanical seals. The frictional heat transfer analysis was carded out to optimize the geometrical parameters of the sealing rings, such as the length, the inner radius and the outer radius. The geometrical parameters of spiral grooves, such as the spiral angle, the end radius, the groove depth, the ratio of the groove width to the weir width and the number of the grooves, were optimized by regarding the maximum bearing force of fluid film as the optimization objective with the coupling effect considered. The depth of spiral groove was designed to gradually increase from the end radius of spiral groove to the outer radius of end face in order to decrease the weakening effect of thermal deformation on the hydrodynamic effect of spiral grooves. The end faces of sealing rings were machined to form a divergent gap at inner radius, and a parallel gap will form to reduce the leakage rate when the thermal deformation takes place. The improved spiral groove mechanical seal possesses good heat transfer performance and sealing ability.展开更多
The 30 mm thick ASTM4130 steel pipe was fabricated by gas tungsten arc welding and shielded metal arc welding under quenched and tempered conditions. Whereafier, the mechanical properties of welded joints of both V gr...The 30 mm thick ASTM4130 steel pipe was fabricated by gas tungsten arc welding and shielded metal arc welding under quenched and tempered conditions. Whereafier, the mechanical properties of welded joints of both V groove and combination double V groove were measured, while the microstructure feature and fracture morphology of both welded joints were investigated. Moreover, the effect of groove shapes on the properties of welded joints was explored. The results show that the welding efficiency of the combination double V groove joint is as two times as that of the V groove joint. But the hardness and toughness of the heat-affected zone （HAZ） with combination double V groove can not satisfy the requirements. Also, the coarse grain heat-affected zone （CGHAZ） of the cap layer is mainly composed of granular bainite, tempered martensite and a small amount of carbon-free bainite, and the fractured swface of the fusion line is entirely dominated by the quasi-cleavage mode. That the mechanical properties of the combination double V groove are lower than that of the V groove lie in the penetration ratio, welding heat input, and the areas and distribution feature of brittle zones. The combination double V groove is not suitable for the fabricating of ASTM4130 steel.展开更多
文摘The coupling effect among the flow of fluid film, the frictional heat of fluid film and the thermal deformation of sealing rings is inherent in mechanical seals. The frictional heat transfer analysis was carded out to optimize the geometrical parameters of the sealing rings, such as the length, the inner radius and the outer radius. The geometrical parameters of spiral grooves, such as the spiral angle, the end radius, the groove depth, the ratio of the groove width to the weir width and the number of the grooves, were optimized by regarding the maximum bearing force of fluid film as the optimization objective with the coupling effect considered. The depth of spiral groove was designed to gradually increase from the end radius of spiral groove to the outer radius of end face in order to decrease the weakening effect of thermal deformation on the hydrodynamic effect of spiral grooves. The end faces of sealing rings were machined to form a divergent gap at inner radius, and a parallel gap will form to reduce the leakage rate when the thermal deformation takes place. The improved spiral groove mechanical seal possesses good heat transfer performance and sealing ability.
基金supported and funded in part by a grant(Project No.ZR2013EEQ027)from the Natural Science Foundation of Shandong Provincea grant(Project No.14CX02066A)from the Fundamental Research Funds for the Central Universities of China
文摘The 30 mm thick ASTM4130 steel pipe was fabricated by gas tungsten arc welding and shielded metal arc welding under quenched and tempered conditions. Whereafier, the mechanical properties of welded joints of both V groove and combination double V groove were measured, while the microstructure feature and fracture morphology of both welded joints were investigated. Moreover, the effect of groove shapes on the properties of welded joints was explored. The results show that the welding efficiency of the combination double V groove joint is as two times as that of the V groove joint. But the hardness and toughness of the heat-affected zone （HAZ） with combination double V groove can not satisfy the requirements. Also, the coarse grain heat-affected zone （CGHAZ） of the cap layer is mainly composed of granular bainite, tempered martensite and a small amount of carbon-free bainite, and the fractured swface of the fusion line is entirely dominated by the quasi-cleavage mode. That the mechanical properties of the combination double V groove are lower than that of the V groove lie in the penetration ratio, welding heat input, and the areas and distribution feature of brittle zones. The combination double V groove is not suitable for the fabricating of ASTM4130 steel.
