本文選題：管道氣動噪聲 + 計算氣動聲學��； 參考：《華北電力大學》2017年碩士論文

【摘要】：電能是國家重要的戰(zhàn)略能源,對于國民經濟影響深遠,而鍋爐泄漏導致的非計劃停機嚴重影響了發(fā)電容量,因此對鍋爐泄漏的監(jiān)測和準確定位十分重要。在諸多監(jiān)測泄漏手段中,聲學監(jiān)測方法潛力巨大、優(yōu)勢十分突出,聲學監(jiān)測技術在國內外電廠都得到了廣泛的應用,然而由于聲學理論基礎和對爐內聲學特性的研究不夠完善,聲學診斷技術仍然存在許多問題。當爐內管道發(fā)生泄漏時,泄漏噴流沖擊附近的管道形成次級聲源,由于次級聲源的干擾,使得聲學診斷和定位準確性大大降低,為了使得爐內聲學檢測定位更加精確和具有時效性,對次級聲源的研究刻不容緩。為了深入探究爐內管道氣體繞流及氣動噪聲的特性,本文采用計算氣動聲學(CAA)方法,利用流體力學仿真軟件FLUENT,選用大渦模擬方法建立模型,對泄漏噴流在運動過程中沖擊管道所形成的一系列流場及聲場特性進行了研究,分析了單管道繞流風吹聲的流場及聲輻射特性,多管道繞流所形成的管道耦合效應,以及管道繞流風吹聲的聲源機制和聲輻射效應。為了驗證數值模擬方法的準確性和可行性,在常溫常壓下進行實驗,與數值模擬結果吻合度較好。通過對結果的分析,得到的主要結論有:流場特性可以很好的解釋爐內管道繞流氣動噪聲的聲輻射特性。單管道的管道繞流聲場的聲輻射指向性與聲偶極子的輻射特性相似。來流速度越大,管道間的耦合效應越強。來流角度和管道間距以及管道單元結構對于管道的流場和聲輻射效應影響很大,主要結論有:增大管道間距,管道間的耦合效應降低;改變來流角度,在垂直于來流面的方向上容易出現動壓及聲壓級的極大值;三管道的相對排列位置不同,上游管道后方脫落的漩渦撞擊下游管道后對動壓及聲壓級的增強效果不同。
[Abstract]:Electric energy is an important national strategic energy, which has far-reaching influence on the national economy. The unplanned shutdown caused by boiler leakage seriously affects the power generation capacity, so it is very important to monitor and locate boiler leakage accurately. Among the many leakage monitoring methods, acoustic monitoring methods have great potential and outstanding advantages. Acoustic monitoring technology has been widely used in power plants at home and abroad. However, due to the sound theory foundation and the study of acoustic characteristics in the furnace is not perfect. There are still many problems in acoustic diagnostic technology. When the pipeline in the furnace leaks, the leakage jet impinges on the nearby pipeline to form the secondary sound source. Because of the interference of the secondary sound source, the accuracy of acoustic diagnosis and location is greatly reduced. In order to make the localization of acoustic detection in furnace more accurate and timely, it is urgent to study secondary sound sources. In order to deeply investigate the characteristics of gas flow and aerodynamic noise in the furnace, this paper adopts the method of computational aero acoustics (CAA), uses fluid dynamics simulation software fluent, and chooses the method of large eddy simulation to establish the model. The characteristics of a series of flow field and sound field formed by the impingement of the leakage jet in the moving process are studied. The characteristics of the flow field and sound radiation of the wind blowing around the single pipe and the coupling effect of the multi-pipe flow around the pipe are analyzed. And the sound source mechanism and sound radiation effect of the wind blowing around the pipeline. In order to verify the accuracy and feasibility of the numerical simulation method, experiments were carried out at room temperature and atmospheric pressure, and the results were in good agreement with the numerical simulation results. Through the analysis of the results, the main conclusions are as follows: the characteristics of the flow field can well explain the acoustic radiation characteristics of the aerodynamic noise around the pipe in the furnace. The acoustic radiation directivity of the sound field around the pipe is similar to that of the acoustic dipole. The greater the speed of the incoming flow, the stronger the coupling effect between the pipes. The flow field and acoustic radiation effect are greatly affected by the flow angle and the spacing of the pipeline and the structure of the pipeline unit. The main conclusions are as follows: the coupling effect between the pipes decreases with the increase of the distance between the pipes, and the flow angle is changed. The maximum of dynamic pressure and sound pressure level is easy to appear in the direction perpendicular to the incoming flow surface, and the relative arrangement of the three pipelines is different, and the enhancement effect of the vortex falling off from the back of the upstream pipeline to the downstream pipeline is different.
【學位授予單位】：華北電力大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：O357.5;TM621.2

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本文編號：2010293