【摘要】：管道作為重要的介質(zhì)傳輸元件,在化工、電力、石油等行業(yè)有著極其重要的應(yīng)用,但是管道振動問題已經(jīng)嚴(yán)重制約了裝備的大型化發(fā)展、降低裝備運行的可靠性,甚至還會造成嚴(yán)重事故,因此對輸流管道進行動力學(xué)特性分析和減振研究顯得極為重要。本文結(jié)合河南某電廠再熱熱段蒸汽管道的振動問題對輸流管道進行動力學(xué)特性研究并提出減振建議。本文通過對輸流管道進行動力學(xué)分析和減振研究,分別從固體側(cè)和流體側(cè)對影響管道振動的因素進行分析,并對管道進行瞬態(tài)動力學(xué)分析,研究其在非穩(wěn)態(tài)流動下管道結(jié)構(gòu)的動力學(xué)響應(yīng),同時利用專業(yè)管道分析軟件對電廠再熱熱段蒸汽管道進行分析。首先本文以ANSYS Workbench為平臺著重研究管道壁厚、約束位置、管道內(nèi)徑、位移約束等對管道固有頻率的影響,同時考慮流固耦合對管道固有頻率的影響,并且對不同約束條件下的彎管進行瞬態(tài)動力學(xué)分析。其次以Fluent軟件為分析平臺,在ANSYS ICEM中對一半的管系進行建模并進行結(jié)構(gòu)網(wǎng)格劃分,分別對穩(wěn)態(tài)和非穩(wěn)態(tài)流動下流體的運動特性進行分析。結(jié)論認(rèn)為管道壁厚、管道內(nèi)徑和位移約束對管道的固有頻率有較大的影響;約束位置對管道的動力學(xué)特性影響較大;由于管內(nèi)流體是過熱蒸汽,所以考慮流固耦合和不計流固耦合對管道的固有頻率影響不大;在對流體進行流場分析過程中發(fā)現(xiàn)在彎頭處出現(xiàn)對旋的二次流動。接著利用管道分析軟件CAESARⅡ?qū)φ麄�管系進行靜力學(xué)和動力學(xué)分析,并結(jié)合上述的結(jié)論,給管系增加阻尼和位移約束,發(fā)現(xiàn)增加阻尼對管道的一次應(yīng)力、二次應(yīng)力和管道的固有頻率都會產(chǎn)生增大的影響,增加阻尼和位移約束會使管道的一次應(yīng)力和固有頻率增大,管道的二次應(yīng)力降低,管道節(jié)點的最大位移明顯減小,從原來的257.246mm減小到23.417mm,隨著位移約束的增大,一次應(yīng)力略微增大,二次應(yīng)力明顯降低,固有頻率不變。最后給出了此再熱熱段蒸汽管道的減振意見。本文通過對輸流管道進行動力學(xué)特性分析,提出減振方案建議,對減小管道系統(tǒng)二次應(yīng)力、提高管道的固有頻率、降低操作工況下管道系統(tǒng)的最大位移有明顯的效果。
[Abstract]:As an important medium transmission element, pipeline has very important applications in chemical industry, electric power, petroleum and other industries. However, pipeline vibration has seriously restricted the large-scale development of equipment and reduced the reliability of equipment operation. Even serious accidents can be caused, so it is very important to analyze the dynamic characteristics and reduce vibration of the pipeline. Based on the vibration of steam pipeline in reheat section of a power plant in Henan Province, this paper studies the dynamic characteristics of the pipeline and puts forward some suggestions for vibration reduction. In this paper, the dynamic analysis and vibration absorption analysis of the pipeline are carried out, and the factors affecting the pipeline vibration are analyzed from the solid side and the fluid side, respectively, and the transient dynamic analysis of the pipeline is carried out. The dynamic response of pipeline structure under unsteady flow is studied, and the steam pipeline in reheat section of power plant is analyzed by professional pipeline analysis software. Firstly, based on ANSYS Workbench platform, the influence of pipe wall thickness, constrained position, pipeline inner diameter and displacement constraint on the natural frequency of pipeline is studied, and the influence of fluid-solid coupling on the natural frequency of pipeline is considered at the same time. At the same time, the transient dynamic analysis of the bends under different constraint conditions is carried out. Secondly, using Fluent software as the analysis platform, half of the pipe system is modeled in ANSYS ICEM and the structural meshes are divided to analyze the motion characteristics of the fluid under steady and unsteady flow respectively. It is concluded that the thickness of the pipe wall, the inner diameter and the displacement constraint have great influence on the natural frequency of the pipeline, and the constrained position has a great influence on the dynamic characteristics of the pipeline. Because the fluid in the pipe is superheated steam, the fluid-solid coupling and non-fluid-solid coupling have little effect on the natural frequency of the pipeline. During the flow field analysis of the fluid, it is found that there is a counter-rotating secondary flow at the elbow. Then the static and dynamic analysis of the whole pipe system is carried out by using the pipeline analysis software CAESAR 鈪，

本文編號：2374486