The Research On Micro-gap Flow Field And Sealing Performance In The Sprial Grooved Gas Seals Based On CFD

The technology of dry gas seal comes from the developed industrial countries, and our products have relied on import for a long time.Our research on the dry gas seal technology and development of its product are just at the beginning stage.The whole system of design,development and manufacture of dry gas seal product has not yet been set up.Therefore carrying out its research has important significance for improving our level of dry gas seal technology.In this paper, one of CFD software-Fluent software was used for simulating fl-ow field of spiral groove dry gas seal,theoretical calculations results and testing resul-ts were combined to study the e spiral groove gas seal micro-gap flow and sealing properties.Theoretical analysis of laminar and turbulence was carried out separately from the perspective of fluid mechanics.At the same time, two different flowing state of internal micro-groove three-dimensional space flow were simulated separately by the software of Fluent, and then gained the flow field pressure distribution, velocity distribution and Leakage.According to flow factor, theoretical calculation was done by simulating results.And the leakage of two kinds of flow pattern were compared and analyzed by the leakage of experiment.So compositing the above two kinds of results, show that fluid state in spiral groove gas face seal is based on laminar flow in certain operating conditions.Dry gas seal flow field of the spiral groove, circular groove, straight-line groove with the same geometric parameters were simulated by Fluent, and their groove parameters were optimized,last but not least, the three kinds of optimized groove were compared.The stability and reliability of spiral groove dry gas seal operation depends on of the size of stiffness film, so gas film stiffness is important to for maintaining the stability of spiral groove gas seal.In the same specific conditions,internal micro-groove three-dimensional space flow of six different gas film thickness were simulated by the software of Fluent, and then the flow field pressure distribution and radial pressure distribution were gained. So firstly, gas film thrust of different gas film thickness were obtained through dynamic pressure, then gas film thrust polynomial about gas film thickness was gained through applying least-squares rule to fit, last but not the least, gas film stiffness polynomial about gas film thickness was obtained.The experimental investigation of a YTG-CTII type of groove dry gas seal was conducted on the 1800r/min high-speed centrifugal compressor test device in ChengDu YiTong Seal Co.,Ltd.The research finished overall plan of instrumentation system and hardware configuration, tested leakage,power lose and gaseous film rigidity, obtained test results and analyzed error between test and simulation data. Comparing some data from experiments with that of approximate simulation,the results show that using CFD to simulate the spiral groove dry gas seal flow field was feasible.