ACTA AERONAUTICAET ASTRONAUTICA SINICA >
Numerical and experimental research on performance of swirl brakes for the static and dynamic characteristics of seals
Received date: 2014-09-15
Revised date: 2015-06-15
Online published: 2015-06-30
Supported by
National Natural Science Foundation of China (11302133); Aeronautical Science Foundation of China (20140454); Education Fund Item of Liaoning Province (L2013071)
The seal dynamic characteristics play an important role in rotating machinery rotor system stability. The use of swirl brakes at the inlet of seals is an effective method to improve the seal stability. The paper designs five kinds of seals without and with swirl brakes. Numerical and experimental research on the performances of swirl brakes for the static and dynamic characteristics of seals are investigated. The paper sets up the swirl brake seal static characteristics CFD numerical model to analyze the performance of swirl brakes on seal leakage, the tangential velocity and pressure distribution. Experiments are presented to identify the dynamic characteristics coefficients using an improved impedance method based on unbalanced synchronous excitation method. The results show that compared to the traditional seals, the seals with brake seals have less leakage, lower fluid tangential velocity and smaller circumferential pressure difference. With the increase of swirl brake quantity in the circumferential direction and swirl brake radial length, this effect increases gradually. It is the main reason why swirl brakes reduce flow-induced force. Preswirl is a main factor for seal cross stiffness coefficients. The seal cross stiffness coefficients increase with inlet/outlet pressure ratio and rotational speed. The swirl brakes can effectively reduce the cross-couple stiffness and increase the direct damping for a variable conditions. It is believed that the results of this study will assist in improving the design of annular seal.
Key words： swirl brakes; seals; vibration; static characteristics; dynamic characteristics
SUN Dan , WANG Shuang , AI Yanting , WANG Keming , XIAO Zhonghui , LI Yun . Numerical and experimental research on performance of swirl brakes for the static and dynamic characteristics of seals[J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2015 , 36(9) : 3002 -3011 . DOI: 10.7527/S1000-6893.2015.0184
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