超临界二氧化碳微尺度干气密封性能分析

Performance Analysis of Supercritical Carbon Dioxide Micro-scale Dry Gas Seals

为研究超临界二氧化碳干气密封的密封性能,在考虑实际气体效应、惯性效应和湍流效应的情况下,利用Solidworks软件建立一个周期的螺旋槽计算域几何模型,导入ICEM软件进行结构化网格划分,采用REFPROP软件获取超临界二氧化碳物性相态数据,并将这些物性参数编译成CFD的计算程序对超临界二氧化碳干气密封流场进行数值模拟。研究结果表明:在干气密封中超临界二氧化碳的密度和黏度从外径到内径先升高后降低,在槽根部最大,而温度沿外半径到内半径的方向逐级递减;随着螺旋槽深度的增加开启力先增大后减小,而泄漏量随着槽深单调增加,其中槽深对开启力的影响较小,对泄漏量的影响较大;转速的增大使气膜开启力和泄漏量均单调增加,而气膜间隙的增加使气膜开启力减小,泄漏量增加。综合考虑密封稳定性,当气膜厚度为3.05μm、槽深为5.05μm时,研究的超临界二氧化碳干气密封的整体密封性能达到最佳。

In order to study the sealing performance of supercritical carbon dioxide(S-CO2)dry gas seal,considering the actual gas effect,inertia effect and turbulence effect,a periodic geometric model of spiral groove computational domain was established by using Solidworks software.The model was imported into ICEM software for structured meshing,and the phase data of S-CO2 physical properties were obtained by using REFPROP software.The flow field of S-CO2 dry gas seal was simulated by compiling the obtained physical parameters into CFD program.The results show that the density and viscosity of S-CO2 in the dry gas seal are increased first and then decreased from outer radius to inner radius,and the temperature is decreased gradually from outer radius to inner radius.With the increase of the depth of the spiral groove,the opening force is first increased and then decreased,while the leakage id increased monotonously with the depth of the spiral groove.The groove depth has a larger influence on the leakage,but a smaller influence on the opening force.With the increase of rotating speed,the opening force and leakage of gas film are increased monotonously,while with the increase of film clearance,the opening force of gas film is decreased and the leakage is increased.Considering the sealing stability,the overall sealing performance of the studied S-CO2 dry gas seal is the best when the film thickness is 3.05μm and the groove depth is 5.05μm.