本文選題：水泵水輪機(jī)　切入點(diǎn)：數(shù)值模擬　出處：《哈爾濱工業(yè)大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：近年來為滿足用電需求新建了一批大型火電、核電機(jī)組。大容量機(jī)組的投產(chǎn)使用對電網(wǎng)的穩(wěn)定性以及快速響應(yīng)特性提出了更高的要求，必須建立與之配套的調(diào)節(jié)系統(tǒng)，抽水蓄能電站憑借其良好的調(diào)頻調(diào)峰能力成為電網(wǎng)調(diào)節(jié)的首選，水泵水輪機(jī)的穩(wěn)定性問題也因此成為關(guān)注的焦點(diǎn)。在諸多影響穩(wěn)定運(yùn)行的因素中，無葉區(qū)強(qiáng)烈的動靜干涉及復(fù)雜的壓力脈動是導(dǎo)致運(yùn)行不穩(wěn)定的主要原因之一，嚴(yán)重時會引發(fā)機(jī)組振動、噪聲甚至葉片裂紋，因此有必要對無葉區(qū)壓力特性及脈動機(jī)理進(jìn)行深入的研究，為水泵水輪機(jī)的設(shè)計(jì)及穩(wěn)定運(yùn)行提供參考。 為研究無葉區(qū)的壓力特性，本文采用CFD技術(shù)對國內(nèi)某抽水蓄能電站水輪機(jī)工況下模型和真機(jī)同一單位轉(zhuǎn)速，不同導(dǎo)葉開度以及模型導(dǎo)葉擺動過程進(jìn)行了數(shù)值模擬，對無葉區(qū)壓力脈動進(jìn)行了詳細(xì)的分析，本文主要內(nèi)容如下： （1）根據(jù)真機(jī)實(shí)際運(yùn)行工況點(diǎn)，選取模型6個不同開度進(jìn)行數(shù)值計(jì)算，獲得了外特性及壓力脈動幅值隨開度變化的曲線，并與試驗(yàn)數(shù)據(jù)進(jìn)行了對比。隨后給出了無葉區(qū)壓力脈動頻率的理論預(yù)測并通過數(shù)值模擬進(jìn)行驗(yàn)證，詳細(xì)分析了最優(yōu)工況無葉區(qū)壓力脈動特性及上下游傳播規(guī)律，并對模型無葉區(qū)壓力脈動隨導(dǎo)葉開度變化的規(guī)律進(jìn)行了簡要分析。 （2）選取真機(jī)50%負(fù)荷，最優(yōu)開度以及滿負(fù)荷等3個工況進(jìn)行數(shù)值計(jì)算，分別與模型對應(yīng)的相似工況進(jìn)行了詳細(xì)的對比分析，研究模型與真機(jī)無葉區(qū)壓力脈動頻率成分及幅值大小的異同，探究模型與真機(jī)之間的換算關(guān)系。 （3）對模型采用動網(wǎng)格方法計(jì)算，以18°作為起始開度，模擬導(dǎo)葉左右擺動1°過程中無葉區(qū)壓力脈動特性，，對導(dǎo)葉不同轉(zhuǎn)動狀態(tài)下無葉區(qū)壓力脈動幅值大小，時域以及頻域特性進(jìn)行了研究，最后對比分析了導(dǎo)葉整個擺動過程與導(dǎo)葉定開度過程無葉區(qū)壓力脈動的異同。 研究結(jié)果表明，無葉區(qū)壓力脈動主要頻率是轉(zhuǎn)輪葉片通過頻率及其諧波頻率，此外還存在來自于轉(zhuǎn)輪和尾水管的頻率成分。無葉區(qū)壓力脈動更容易向上游傳播，但不同頻率分量幅值衰減不一。不同導(dǎo)葉開度對無葉區(qū)壓力脈動特性有顯著影響。相似工況下真機(jī)與模型頻率成分基本一致，但幅值大小差異較大且沒有明顯的換算關(guān)系。導(dǎo)葉擺動過程無葉區(qū)9倍頻以下頻率成分豐富，相對定開度峰峰值明顯增大。
[Abstract]:In recent years, in order to meet the demand for electricity, a new batch of large thermal power and nuclear power units and large capacity units have been built up and put forward higher requirements for the stability of the power network and the characteristics of rapid response. It is necessary to establish a matching regulation system. Pumped-storage power station has become the first choice of power network regulation by virtue of its good capacity of frequency modulation and peak-shaving, and the stability of pump turbine has become the focus of attention. Among the factors that affect the stable operation of pumped-storage power station, One of the main causes of unstable operation is the strong dynamic and static interference and complex pressure fluctuation in the leafless area, which can lead to vibration, noise and even blade cracks in severe cases. Therefore, it is necessary to deeply study the pressure characteristics and pulsation mechanism in the leafless region to provide a reference for the design and stable operation of the pump turbine. In order to study the pressure characteristics in the vaneless region, a numerical simulation was carried out by using CFD technique to simulate the model and the actual unit rotating speed, the different guide vane opening degree and the model guide vane swing process under the same unit speed and the same unit speed of the turbine in a domestic pumped storage power station. The pressure fluctuation in the leafless region is analyzed in detail. The main contents of this paper are as follows:. 1) according to the actual operating conditions of the real machine, six different openings of the model are selected for numerical calculation, and the curves of the external characteristics and the amplitude of pressure pulsation with the opening degree are obtained. The theoretical prediction of pressure pulsation frequency in vaneless region is given and verified by numerical simulation. The characteristics of pressure fluctuation and the propagation law of upstream and downstream in the optimal condition are analyzed in detail. The variation of pressure pulsation with the opening of the guide vane is analyzed briefly. 2) selecting the 50% load, optimal opening and full load of the real machine to carry out numerical calculation, and comparing and analyzing in detail with the similar working conditions corresponding to the model. The differences and similarities of pressure pulsation frequency components and amplitudes between the model and the real machine are studied, and the conversion relationship between the model and the real machine is discussed. The dynamic grid method is used to calculate the model. With 18 擄as the initial opening, the characteristics of the pressure pulsation in the vaneless region during the 1 擄swing of the guide vane are simulated, and the amplitude of the pressure pulsation in the vaneless region under different rotating conditions of the guide vane is studied. The characteristics in time domain and frequency domain are studied. Finally, the differences and similarities of the pressure pulsation in the vaneless region between the whole swing process of the guide vane and the opening process of the guide vane are compared and analyzed. The results show that the main frequency of pressure pulsation in the leafless region is the frequency and harmonic frequency of the runner blade, in addition, there are frequency components from the runner and the draft tube, and the pressure pulsation in the leafless zone is more easily propagated upstream. However, the amplitude attenuation of different frequency components is different. The pressure pulsation characteristics in the vaneless region are significantly affected by the different guide vane openings. The frequency components of the real machine and the model are basically the same under similar operating conditions. However, the amplitude varies greatly and there is no obvious conversion relationship. The frequency components below 9 times frequency in the leafless region of the guide vane swing process are rich, and the peak value of the relative opening degree increases obviously.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TK730

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