微尺度输流管道考虑热效应的流固耦合振动分析

摘要

研究热环境中输送微流体的微尺度管道流固耦合振动问题。根据线性热弹性理论建立系统振动控制方程，并利用复模态法对其进行求解，得到了系统的固有频率和屈曲失稳临界流速，讨论了温度变化、微尺度效应及管道壁厚对系统振动特性的影响。研究结果表明：提高环境温度会降低系统的固有频率和临界流速；管道和流体的微尺度效应分别会使临界流速升高和降低，但微流体的这种影响会随着温度的升高而逐渐减弱并最终消失；管壁较薄（外径接近微尺度特征尺寸）时，壁厚的变化对固有频率的影响很大，而管壁较厚时，温度变化对固有频率的影响更为明显。%The fluid-structure interaction (FSI)properties of microtubes conveying micro-flow in temperature field were investigated.The governing equation of the system was established based on the linear thermoelastic theory and then solved by using the complex mode method.The natural frequencies and critical flow velocities for buckling instability of the system were obtained and the influences of temperature variation,micro size effect and tube thickness on the vibration characteristics were discussed.The results showed that increasing temperature decreases the natural frequencies and critical flow velocities;the size effect of microtube can increase the critical flow velocities,while the size effect of micro-flow decreases them,moreover,the size effect of micro-flow declines and even disappears with increase in temperatures;the variation of tube thickness greatly affects the natural frequencies when the thickness is smaller (the outer diameter of tube is close to the characteristic length of micro-structures),however temperature variation has dominant effect on the natural frequencies when the thickness is larger.