超临界二氧化碳干气密封实际气体效应和湍流效应分析

Analysis of real gas and turbulence effect of supercritical carbon dioxide dry gas seal

实际气体效应和湍流效应对超临界二氧化碳(S-CO_(2))干气密封性能影响很大。建立了典型的螺旋槽干气密封计算模型,采用CFD软件求解S-CO_(2)干气密封端面流动方程,获取流体在密封槽间隙间的流动状态,研究了不同转速下实际气体效应和湍流效应对密封性能的影响。结果表明:实际气体效应和湍流效应使气膜端面压力分布发生显著变化;实际气体效应会提高气膜开启力和泄漏量,对开启力的增强作用随转速增大而变强,但对泄漏量的影响程度几乎不随转速变化;低转速时,湍流效应对开启力影响微弱,随着转速增大,湍流效应使得开启力急剧增大,且增幅随转速增大而增大;在高转速S-CO_(2)干气密封中,实际气体效应和湍流效应的共同作用使得气膜端面的开启力显著提高,且湍流效应的影响程度大于实际气体效应。

The effects of real gas and turbulence have a great influence on the performance of supercritical carbon dioxide(S-CO_(2))dry gas seal.A typical spiral groove dry gas seal calculation model is established,and the flow equation on the end face of supercritical carbon dioxide dry gas seal is solved by CFD software to obtain the flow state of fluid between the seal slots.The influence of real gas and turbulence effects on opening force and leakage are investigated under different rotational speed.The results show that both real gas and turbulence effects make the pressure distribution of the gas film change significantly.The real gas effect improves the opening force and leakage of gas film,and the strengthening effect on the opening force becomes stronger with the increase of the rotational speed,while the effect on the leakage almost does not change with the rotational speed.At low rotational speed,the turbulence effect has a weak effect on the opening force.With the increase of rotational speed,the opening force increases sharply due to the turbulence effect,and the increase increases with the increase of rotational speed.In the high speed S-CO_(2) dry gas seal,the combined effect of real gas and turbulence effect makes the opening force of gas film increase significantly,and the turbulence effect is greater than the real gas effect.