气体波动引起的弯曲流道气波机振荡管结构动态响应研究

Investigation on dynamic response of oscillating tube structure of curved channel gas-wave refrigerator caused by gas fluctuation

弯曲流道气波制冷机内气体波动引起的振动行为复杂,而二维数值计算不能对其进行真实的模拟,且实验过程中难以采集气波机的振动信号。为了解决以上问题,对弯曲流道振荡管结构动态响应进行了研究。首先,基于流固耦合数值模拟方法,开发了双开口弯曲流道气波机波转子三维非定常流体流动模型,并对模型进行了可靠性验证;然后,采用傅里叶变换技术提取了振荡管内不规则压力激励载荷,分析了非定常流体激励载荷时域和频域分布规律;最后,分析了波动压力下振荡管结构的动态位移场和应力场,计算了气波机波转子系统固有频率,与相同参数下的直流道振荡管进行了对比。研究结果表明:相对于直流道振荡管,弯曲流道气波机振荡管的最大振幅增加了1.74倍,不利于结构安全运行,但幅值在10-2 mm以下,满足工程设计要求;虽然,振荡管插片振动频率与流激力载荷频率相近,但远离波转子结构的固有频率,因此不会引发结构共振和激烈的强迫振动,能够确保气波机安全平稳地运行。

In order to solve the problems that the vibration behavior caused by gas fluctuations in a gas-wave refrigerator with curved channel was more complex,and the two-dimensional numerical calculation couldn t be simulated and the vibration signal was difficult to collect in the experiment,the dynamic response of the oscillating tube structure with curved channel was studied.Firstly,a three-dimensional unsteady flow model of wave rotor in the double-opening curved channel gas-wave refrigerator was established based on the fluid-structure coupling numerical simulation method,and the reliability of the model was verified.Then,the irregular pressure excitation loads in the oscillating tube were extracted by the Fourier transform method,and the time domain and frequency domain distribution of unsteady fluid excitation loads were analyzed.Finally,the dynamic displacement field and stress field of the oscillating tube under fluctuating pressure were analyzed,and the natural frequency of wave rotor system in the gas-wave refrigerator with curved channel was calculated and compared with that of the straight channel oscillating tube using the same parameters.The experimental results show that the maximum amplitude of the curved channel oscillator tube is increased by 1.74 times than that of the straight channel oscillator tube,but the amplitude is below 10-2 mm,which meets the requirement of engineering design.The vibration frequency of the oscillating tube insert is close to the frequency of the fluid-induced force load,but they are all far away from the natural frequency of the wave rotor,which indicates that the structure will not occur resonance and excessive forced vibration,which can meet the needs of safe operation.