基于流固耦合的多弯管路系统动力学分析

Dynamics analysis of more curved pipe system based on fluid-structure coupling

为研究多弯管路系统的动力学特性,基于流固耦合和有限元原理,对充液L型管道的固有特性进行了数值模拟,并与TMM(传递矩阵法)进行了对比,证明了数值模型的合理性。建立了水下多弯管路的数值模型,进行了流固耦合模态分析,研究了壁厚、管径对管路固有频率的影响规律。并对非定常流下多弯管路系统的动力响应进行了分析,研究了壁厚和波动速度对管道振动的影响规律。研究结果表明:考虑管内、外流体与管道三者耦合时的管道固有频率比只考虑管内流体与管道二者耦合和不考虑耦合时小,但流固耦合作用对管道模态振型的影响较小;管道的固有频率随管径和壁厚的增大而增大,气体与管道之间耦合作用对管道固有频率的影响小于液体;非定常流下,多弯管路的振动幅值随着壁厚的增大而减小,随着波动速度的增大而增大。

In order to study the dynamic characteristics of more curved pipe system , according to the fluid-structure coupling and the finite element theory , the inherent characteristics of L-type pile were simulated .The results were compared with that calculated by TMM （ Transfer Matrix Method ） , which proved that the FE model was rationality . The numerical model of underwater more curved pipe was established , the fluid-structure coupling modal analysis was conducted , and the effects of wall thickness and diameter on the natural frequency were studied .The dynamic response of pipe under the unsteady flow was analyzed , the influence of wall thickness and wave speed on the pipe vibration were researched .The results showed that the natural frequency of pipe system drops when considering the three couplings among outer and inter fluid with pipe , compared with the two coupling between inter fluid with pipe and no coupling .The natural frequency of the pipe increases with the increasing of wall thickness and diameter . For the pipe natural frequency , the coupling effect between gas and pipe is smaller than that between fluid and pipe.Under the unsteady flow , the pipe vibration amplitude deceases with the increasing of wall thickness , and in-creases with the increasing of wave velocity .