三维转子密封系统气流激振的研究

STUDY ON GAS FLOW-INDUCEDVIBRATION FOR A THREE-DIMENSIONAL ROTOR-SEAL SYSTEM

提出了分析三维转子密封系统气流激振流固耦合作用的数值计算方法。首先建立三维转子密封流固耦合模型,然后直接数值求解密封流场的非线性气动力,形成了考虑流固耦合效应的转子密封气流激振问题的分析方法。数值计算表明,对应于不同的转速、压比和预旋,转子振动的各个频率成分的幅值不同,但始终存在着转子一阶临界转速频率成分,而且该成分的幅值随着转速、气流进口压力和正向进气预旋的增高而增大,与工程和试验中的密封气流激振现象有较好的一致性,捕捉到了密封气流激振的基本特性。

A numerical method is put forward, which can be used for analyzing the fluid-solid coupling function of gas flow-induced vibrations in a three-dimensional rotor seal system. First, a nonlinear fluid-solid coupling model is set up for a three-dimensional rotor seal system and then the nonlinear aerodynamic force of a seal device flow field is calculated through a direct numerical simulation method. As a result, an analytical method is brought forth, which evaluates the gas flow-induced vibration problem of a rotor seal system by taking into account the fluid-solid coupling effect.With respect to different speeds, pressure ratios and pre-rotations there are different amplitudes for each individual frequency component of a rotor vibration. However, there is always a frequency component of rotor first-order critical speed. Furthermore, the amplitude of the component will increase with the increase in speed, gas-flow inlet pressure and the positive-direction incoming gas pre-rotation. The above circumstance is found to be in fairly good agreement with the phenomenon of seal gas flow-induced vibrations found in engineering practice and test results.The nonlinear characteristics of the seal gas flow-induced vibrations is captured.