气液两相流作用下输水管道的振动特性

The vibration characteristics of water transmission pipe based on the effects of gas-liquid two-phase flow

为提高输水管道运行的安全性,并为输水管道的改造设计提出合理建议,进行了输水管道在气液两相流作用下管道振动装置的试验.实验结果表明,输水管道中含气率越大,管道不同位置的振动强度差别越大.对下降管道振动的频谱特征分析,发现不同流型下振动频谱图呈现不同特征.统计结果显示,在输水工况范围内,输水管道中气液两相流压力波动的频率约为17Hz.以两端简支输流管道为模型,运用自由振动理论分析了流固耦合作用、管道结构参数以及含气率对管道系统固有频率的影响,通过加强约束和选用质轻抗拉伸管材的方法,可避免输水管道系统发生共振.总之,气体的存在对输水管道安全运行弊大于利,因此在实际工程中管道内的气体应及时排出.

In order to improve the safety of water transmission pipe line and put forward reasonable proposals for the design and transformation of the pipeline, a field test is carried out to study the pipe vibration under gas-liquid two-phase flow. The results showed that the water transmission pipe with larger void fraction can generate more intense vibration at different positions. Through the a nalysis of the vibration spectrum in the downward pipe, it is found that the vibration spectra under different flow regimes show different characteristics. It is concluded that the frequency of pressure fluctuation of gas-liquid two phase flow in water transmission pipe is around 17Hz according to all the operating points in the test. In addition, the model of ＂simply supported pipe at both ends＂ is applied to analyze the effect of fluid-structure interaction, structural parameters and flow parameters on the natural frequency of the pipe system. Strong constraints and light-tensile pipe materials are proposed to avoid the resonance. Taking various factors into consideration, the presence of air in the pipeline does more harm than good, so the air should be promptly discharged in the actual engineering.