输水管道流固耦合振动试验及数值模拟

发布时间：2018-05-30 17:07

  本文选题：输水管道 + 流固耦合　； 参考：《哈尔滨工业大学》2016年硕士论文

【摘要】：输水管道中存在由于流体与管道之间相互作用的流固耦合现象,由于流体流动状态的不稳定,导致流体内部压力失衡而产生了压力波动从而引发管道的振动,这种振动对于弯头、阀门等管道的连接部位的影响,会导致管道漏失现象的发生,在极端情况下可能会发生爆管事故。从保障输水管道安全性的角度出发,本文基于流固耦合理论,对重力流、压力流两种不同供水方式展开研究,通过对稳态振动数据、关阀试验压力数据的采集,以及数值模拟技术的应用,来监测管道流固耦合振动的特性。首先建设了试验管道系统,有机玻璃管作为管材,由高低位水箱、重力流管道、压力流管道组成,管道总长度75m,管道内通过水泵和阀门调节流速在0-2.3m/s之间,在模拟气液两相流流体时,用气泵加气,加气量在0-1.5m3/h之间。在两条管道中,含有上升管段、下降管段、水平管段来模拟输水管道由于地形起伏而存在多种倾斜度管段的情况。设置电动蝶阀控制流速来进行稳态振动试验分析,用加速度传感器采集振动数据;通过气动蝶阀的迅速关闭来模拟关阀水锤试验,用压力传感器采集水锤压力变化数据。对试验数据进行理论分析和处理结果表明,对于稳态振动试验,在单相流中,管道内径向振动强度较小,而轴向振动强度随着流速增加而增加,在气液两相流中,由于气体的存在导致管道振动情况变得复杂,下降管段处管道振动受含气率的影响很大,对比单相流,在相同流速下,轴向振动和径向振动强度都较大,说明了水中气体的存在会使管道在稳态情况下振动更加剧烈,不利于管道稳定运行。对于关阀水锤压力试验,关阀水锤的水锤升压值随着流速增加而增加,而在相同流速下,随着加气量的增加,关阀水锤升压值减小,这是由于气液两相流中气体的可压缩性,有效的减弱了关阀水锤的强度。说明在极端情况流态变化的情况下,流体中气体的存在会对管道产生一定的保护作用。在数值模型分析中,通过ANSYS Workbench平台进行关阀试验数值模拟研究。通过建立与试验管道情况类似的物理模型进行单向流固耦合数值分析,得到了管道流体压力变化云图及管壁形变变化云图,对水锤现象有了更加直观的分析。通过对输水管道中流固耦合现象多角度,多工况的全面分析,总结了输水管道流固耦合振动特点,这些试验数据与结论对输水管道的设计、管理提供了理论基础,具有一定的参考价值。
[Abstract]:The fluid-solid coupling phenomenon exists in the pipeline because of the interaction between the fluid and the pipeline. Because of the instability of the fluid flow state, the internal pressure of the fluid is out of balance and the pressure fluctuates, which leads to the vibration of the pipeline. The effect of this vibration on the connection part of the pipe, such as elbows and valves, will lead to the leakage of the pipe, and in extreme cases, the pipe burst may occur. From the point of view of ensuring the safety of water conveyance pipeline, based on the theory of fluid-solid coupling, this paper studies two different water supply modes, gravity flow and pressure flow, through the collection of steady state vibration data and valve closing test pressure data. And the application of numerical simulation technology to monitor the characteristics of fluid-solid coupling vibration of pipeline. First of all, the test pipe system was built, and the plexiglass pipe was used as the pipe material, which was composed of high and low water tank, gravity flow pipe and pressure flow pipe. The total length of the pipe was 75m. The flow velocity was adjusted between 0-2.3m/s by water pump and valve in the pipeline. In the simulation of gas-liquid two-phase flow, the gas pump is used to aerate and the amount of gas added is between 0-1.5m3/h. In the two pipelines, there are ascending, descending and horizontal pipe sections to simulate the situation that there are many kinds of inclined pipe segments due to the topographic fluctuation of the pipeline. Setting the electric butterfly valve to control the velocity to carry on the steady state vibration test analysis, using the acceleration sensor to collect the vibration data, through the pneumatic butterfly valve to close quickly to simulate the shutoff valve water hammer test, use the pressure sensor to collect the water hammer pressure change data. The theoretical analysis and processing results of the experimental data show that, for steady state vibration test, the radial vibration intensity in the single phase flow is small, while the axial vibration intensity increases with the increase of the flow velocity, and in the gas-liquid two-phase flow, the axial vibration intensity increases with the increase of the velocity of flow. Due to the existence of gas, the pipeline vibration becomes more complicated, and the pipeline vibration at the descending section is greatly affected by the gas content. Compared with the single-phase flow, the axial vibration and radial vibration intensity are larger at the same flow velocity. It is shown that the existence of gas in water will make the pipe vibration more intense under steady state, which is not conducive to the steady operation of the pipeline. For the shutoff valve water hammer pressure test, the water hammer pressure rise value of the shutoff valve water hammer increases with the increase of the velocity of flow, while at the same velocity, with the increase of the amount of gas added, the pressure rise value of the shutoff valve water hammer decreases because of the compressibility of the gas in the gas-liquid two-phase flow. Effectively weakens the strength of the shutoff water hammer. It shows that the existence of gas in the fluid will protect the pipeline in extreme case. In the numerical model analysis, the numerical simulation of closing valve test is carried out through ANSYS Workbench platform. By establishing a physical model similar to that of the experimental pipeline, the unidirectional fluid-solid coupling numerical analysis is carried out, and the cloud diagram of the fluid pressure variation and the deformation change of the pipe wall are obtained, and the water hammer phenomenon is analyzed more intuitively. Through the comprehensive analysis of fluid-solid coupling phenomenon in water conveyance pipeline from many angles and working conditions, the characteristics of fluid-solid coupling vibration in water conveyance pipeline are summarized. These experimental data and conclusions provide a theoretical basis for the design and management of water conveyance pipeline. It has certain reference value.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TV134
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本文编号：1956066