發(fā)布時(shí)間：2018-06-30 17:17

  本文選題：水泵水輪機(jī) + 過(guò)渡過(guò)程　； 參考：《武漢大學(xué)》2017年碩士論文

【摘要】：抽水蓄能電站因其具有調(diào)峰調(diào)頻及吸收多余電能的優(yōu)勢(shì)而被廣泛建設(shè)與應(yīng)用,但正是它的調(diào)節(jié)頻繁使得水泵水輪機(jī)常處于劇烈的過(guò)渡過(guò)程當(dāng)中�？栈怯绊懰C(jī)械安全運(yùn)行的重要因素之一,空化腔不斷的生成與潰滅常常導(dǎo)致轉(zhuǎn)輪及導(dǎo)葉等部件嚴(yán)重空蝕,不得不停機(jī)進(jìn)行檢修,甚至引發(fā)劇烈的反水擊現(xiàn)象,造成抬機(jī)等事故。因此對(duì)于水泵水輪機(jī)空化特性的研究具有十分重要的工程價(jià)值,并為抬機(jī)事故機(jī)理分析奠定基礎(chǔ)。而對(duì)于水泵水輪機(jī)過(guò)渡過(guò)程壓力脈動(dòng)時(shí)頻特性的研究則更能全面分析抽水蓄能電站各類不穩(wěn)定現(xiàn)象的根源,并為這些不穩(wěn)定現(xiàn)象的控制措施提供指導(dǎo)。本文分別采用三維CFD方法和一維三維耦合方法研究了水泵水輪機(jī)的空化特性和水泵斷電飛逸過(guò)渡過(guò)程的壓力脈動(dòng)時(shí)頻特性,并分析了壓力脈動(dòng)頻率特性與流態(tài)特性相關(guān)聯(lián),揭示了過(guò)渡過(guò)程中多種頻率的來(lái)源分布及影響;最后通過(guò)模擬球閥關(guān)閉聯(lián)合水泵水輪機(jī)導(dǎo)葉拒動(dòng)飛逸工況,分析了球閥關(guān)閉對(duì)其過(guò)渡過(guò)程外特性及壓力脈動(dòng)特性的影響,為優(yōu)化球閥關(guān)閉規(guī)律以控制脈動(dòng)不穩(wěn)定性奠定了基礎(chǔ)。本文主要工作如下:1.研究了原型水泵水輪機(jī)空化特性:為了規(guī)避空化特性研究中比尺效應(yīng)的問(wèn)題,模擬研究了某原型水泵水輪機(jī)在不同空化系數(shù)下空化特性。發(fā)現(xiàn)水泵水輪機(jī)的空化壓力脈動(dòng)幅值隨空化系數(shù)的降低先增大后減小;揭示了發(fā)源于泄水錐下方的空化腔在形態(tài)、大小及歷時(shí)上的隨機(jī)性是空化壓力脈動(dòng)頻域豐富但幅值較小的根本原因;解釋了空化壓力脈動(dòng)在整個(gè)流道內(nèi)的傳播規(guī)律并分析了空化壓力脈動(dòng)的頻域特性。2.全面分析了水泵斷電飛逸過(guò)渡過(guò)程中壓力脈動(dòng)特性及流態(tài)特性:采用一維三維耦合方法模擬了某模型水泵水輪機(jī)水泵斷電飛逸過(guò)渡過(guò)程,全面定量分析了各個(gè)位置壓力脈動(dòng)頻率特性,研究了流態(tài)特性演變規(guī)律及其與壓力脈動(dòng)特性的關(guān)聯(lián)。發(fā)現(xiàn)了高頻低幅,高頻高幅,中頻中幅,低頻高幅這四種典型的頻率類型;揭示了各種頻率的來(lái)源及空間影響范圍,發(fā)現(xiàn)高頻信號(hào)是由于轉(zhuǎn)輪旋轉(zhuǎn)引起的,主要影響無(wú)葉區(qū),低頻是由工況區(qū)轉(zhuǎn)換導(dǎo)致的,影響整個(gè)流道,中頻信號(hào)主要影響尾水管區(qū)域,其中中低頻是由高能量的螺旋渦帶引起的,中高頻是由能量較小的螺旋渦帶及尾水管邊壁的片狀渦帶旋轉(zhuǎn)產(chǎn)生的;分析了整個(gè)過(guò)渡過(guò)程中蝸殼壓強(qiáng),轉(zhuǎn)輪內(nèi)流線及尾水管渦帶的演變規(guī)律,定性上解釋了在水泵駝峰區(qū)及水輪機(jī)水輪機(jī)反S區(qū)流態(tài)惡化是導(dǎo)致宏觀參數(shù)振動(dòng)及中頻頻率豐富的根本原因。3.分析了飛逸過(guò)渡過(guò)程中球閥關(guān)閉的影響:采用一維三維耦合方法模擬了某模型水泵水輪機(jī)在飛逸過(guò)渡過(guò)程中兩種球閥關(guān)閉工況,分析了球閥關(guān)閉對(duì)過(guò)渡過(guò)程中宏觀參數(shù)及壓力脈動(dòng)的影響。發(fā)現(xiàn)飛逸過(guò)渡過(guò)程中球閥先快后慢關(guān)閉在解決調(diào)保矛盾及降低轉(zhuǎn)輪受力方面要優(yōu)于線性關(guān)閉;分析了無(wú)葉區(qū)內(nèi)速度脈動(dòng)及回流特性,發(fā)現(xiàn)無(wú)葉區(qū)縱向斷面中部會(huì)形成回流,回流區(qū)域個(gè)數(shù)為轉(zhuǎn)輪葉片數(shù),回流在整個(gè)反S區(qū)均會(huì)存在,宏觀流量的變化會(huì)影響正向流動(dòng)和回流區(qū)域的分布。本文完成了水泵水輪機(jī)空化特性及過(guò)渡過(guò)程中振動(dòng)特性的研究,全面定量地揭示了水泵水輪機(jī)在過(guò)渡過(guò)程中的頻率特性。研究成果補(bǔ)充了現(xiàn)有對(duì)水泵水輪機(jī)空化特性及過(guò)渡過(guò)程中壓力脈動(dòng)時(shí)頻特性及流態(tài)特性認(rèn)識(shí)的不足,所得結(jié)論為將來(lái)研究水泵水輪機(jī)在極端過(guò)渡中空化腔潰滅反水擊問(wèn)題及減小機(jī)組振動(dòng)措施奠定了基礎(chǔ)。
[Abstract]:Pumped storage power station is widely constructed and applied because of its advantages of peak frequency modulation and absorption of excess electric energy, but it is its frequent adjustment that the pump turbine is often in a violent transition process. Cavitation is one of the important factors affecting the safe operation of hydraulic machinery. The continuous formation and collapse of the cavitation cavity often lead to the wheel. As well as the serious cavitation of the guide vane and other parts, it has to stop for overhaul and even cause severe backwater shock and cause accidents. Therefore, it is of great engineering value to study the cavitation characteristics of the pump turbine, and lay the foundation for the analysis of the mechanism of the lift. The study of characteristics can make a comprehensive analysis of the root causes of various instability phenomena in pumped storage power stations and provide guidance for the control measures of these unstable phenomena. In this paper, the three-dimensional CFD method and one dimensional three-dimensional coupling method are used to study the cavitation characteristics of the pump turbine and the time frequency characteristics of the pressure pulsation in the runaway process of the water pump. The relationship between the frequency characteristics of pressure pulsation and the flow characteristics is analyzed, and the source distribution and influence of various frequencies in the transition process are revealed. Finally, the effect of the shutoff on the characteristics of the transition process and the pressure pulsation characteristics of the pump valve is analyzed by simulating the shutoff of the valve and the effect of the pressure pulsation characteristics. The main work of this paper is to control the fluctuating instability. The main work of this paper is as follows: 1. the cavitation characteristics of the prototype pump turbine are studied. In order to avoid the problem of the scale effect in the study of the cavitation characteristics, the cavitation characteristics of a prototype pump turbine under the different cavitation coefficients are simulated and studied. The cavitation pressure fluctuation amplitude of the pump turbine is found. With the reduction of cavitation coefficient, it is revealed that the randomness of cavitation cavity originating under the discharge cone in shape, size and diachronic is the root cause of the rich but small amplitude in the frequency domain of cavitation pressure pulsation. The propagation rules of cavitation pressure pulsation in the whole flow channel are explained and the frequency domain characteristic of cavitation pressure pulsation.2 is analyzed. The characteristics of pressure pulsation and flow state in the process of water cut and runaway transition are analyzed. A one-dimensional three-dimensional coupling method is used to simulate the transition process of a model pump water pump, and the frequency characteristics of pressure pulsation in each position are analyzed. The evolution of flow characteristics and the characteristics of pressure pulsation are studied. The four typical frequency types, such as high frequency and low amplitude, high frequency and high amplitude, medium frequency medium amplitude and low frequency and high amplitude, are found. The sources of various frequencies and the range of spatial influence are revealed. It is found that the high frequency signal is caused by the rotation of the wheel, which mainly affects the non leaf area, the low frequency is caused by the conversion of the working condition area, and the main channel is influenced by the medium frequency signal. The middle low frequency is caused by the high energy spiral vortex belt, and the middle and high frequency is produced by the small spiral vortex belt and the flake vortex band of the side wall of the tail pipe. The variation law of the volute pressure, the inner flow line and the tail pipe vortex belt in the whole transition process is analyzed, and the water pump hump area and the water are explained qualitatively. The deterioration of the flow state in the reverse S zone of the turbine turbine is the root cause of the vibration of the macroscopic parameters and the rich frequency of the intermediate frequency. The effect of the shutoff of the ball valve in the process of flight transition is analyzed by.3.. The one dimension three-dimensional coupling method is used to simulate the closing of two kinds of ball valves in a model pump turbine during the runaway transition process, and the transition of the ball valve closing to the transition is analyzed. The effect of the macro parameters and pressure pulsation in the process is found. It is found that the ball valve is better than the linear closure in solving the contradiction of the adjustment and reducing the force of the runner, and the velocity fluctuation and reflux characteristics in the no leaf area are analyzed. The reflux exists in the whole anti S region. The change of the macroscopic flow will affect the distribution of the forward flow and the reflux region. This paper has completed the study on the cavitation characteristics of the pump turbine and the vibration characteristics during the transition process. The frequency characteristics of the pump turbine during the transition process are comprehensively and quantitatively revealed. The research results complement the existing water pump turbine. The characteristics of mechanical cavitation and the time frequency characteristics and flow characteristics of pressure pulsation in the process of transition are insufficient. The conclusion is the foundation for the future study of the pump turbine in the collapse of the reverse water shock in the extreme transition cavity and the measures to reduce the vibration of the unit.
【學(xué)位授予單位】：武漢大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TV743;TV734

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本文編號(hào)：2086235