超临界二氧化碳迷宫密封动力特性研究

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振动与冲击 ›› 2020, Vol. 39 ›› Issue (22) : 128-136.

论文

超临界二氧化碳迷宫密封动力特性研究

尹露1，张万福1，顾乾磊1，马凯1，陈璐琪1，李春1，杨建刚2

作者信息 +

Study on dynamic characteristics of labyrinth seals with supercritical carbon dioxide

YIN Lu1，ZHANG Wanfu1，GU Qianlei1，MA Kai1，CHEN Luqi1，LI Chun1，YANG Jiangang2

Author information +

文章历史 +

摘要

超临界二氧化碳(S-CO2)布雷顿循环正广泛应用于各类透平机械。本文以S-CO2为工质，采用计算流体力学方法建立迷宫密封全三维数值分析模型，应用基于微元轨迹的密封动力特性系数理论识别方法获取密封动力特性系数。研究以S-CO2为工质的迷宫密封在不同进口压力、进口温度及转速下的动静特性。研究表明：密封直接复合刚度具有较强的频率依赖性，交叉复合刚度和直接阻尼频率依赖性相对较小。密封有效阻尼随进口压力、转子转速增加而增大，随进口温度减小而增大。有效阻尼在低频下（小于100Hz）较大，具有较大频率依赖性，且进口压力为8.1MPa时的有效阻尼约为7.7MPa时的147.2%~187.7%，进口温度为398.15K时的有效阻尼约为318.15K时的68.8%~69.6%，转速为20000rpm时的有效阻尼约为10000rpm时的178.8%~205.8%。随高涡动频率增加（100Hz~260Hz），有效阻尼系数降低，并均趋于定值，频率依赖性较小。随进口压力增大、进口温度降低，密封泄漏量不断增加，转速对密封泄漏量影响较小。

Abstract

The Brayton cycle based on supercritical carbon dioxide (S-CO2) is being applied widely in turbo machineries.In the paper, a three-dimensional numerical model of a labyrinth seal with S-CO2 as working fluid was established by using the computational fluid dynamics method.The dynamic coefficient was obtained by using the infinitesimal trajectory method.The dynamic and static characteristics of the labyrinth seal at different inlet pressure, inlet temperature and speed were studied.The results show that the direct complex dynamic stiffness has strong frequency dependence, while the cross-coupled complex dynamic stiffness and direct damping are of relatively small frequency dependence.The effective damping coefficient increases with the increase of inlet pressure and rotational speed, and with the decrease of inlet temperature.The effective damping coefficient, greater at low frequencies(less than 100 Hz), is more dependent on frequency.The effective damping at an inlet pressure of 8.1 MPa is about 147.2%—187.7% of that at 7.7 MPa, the effective damping at an inlet temperature of 398.15 K is about 68.8%—69.6% of that at 318.15 K, and the effective damping at a rotational speed of 20 000 r/min is about 178.8%—205.8% of that at 10 000 r/min.With the whirling frequency increasing(100—260 Hz), the effective damping coefficient, which is less dependent on frequency, decreases and tends to be constant.The leakage flowrate of the labyrinth seal increases with the increase of inlet pressure, and decreases with the increase of inlet temperature.The rotational speed has minimum effect on the leakage flowrate.

导出引用

尹露1，张万福1，顾乾磊1，马凯1，陈璐琪1，李春1，杨建刚2. 超临界二氧化碳迷宫密封动力特性研究[J]. 振动与冲击, 2020, 39(22): 128-136

YIN Lu1，ZHANG Wanfu1，GU Qianlei1，MA Kai1，CHEN Luqi1，LI Chun1，YANG Jiangang2. Study on dynamic characteristics of labyrinth seals with supercritical carbon dioxide[J]. Journal of Vibration and Shock, 2020, 39(22): 128-136

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