燈泡貫流式水電站廠房流固耦合動力特性研究
發(fā)布時間：2018-09-19 10:26
【摘要】：燈泡貫流式水電站一般為河床式,是開發(fā)低水頭水力資源最合適的方式,由于其水力效率高、有較大的單位流量和較高的單位轉(zhuǎn)速、土建工程量少、投資小見效快等優(yōu)點(diǎn),在國內(nèi)外實(shí)際工程中得到了廣泛應(yīng)用。燈泡貫流式水電站廠房多為擋水廠房,本身作為樞紐擋水建筑物的一部分,且機(jī)組流道尺寸巨大,水體與結(jié)構(gòu)的相互作用對廠房結(jié)構(gòu)特性影響很大。水電站在運(yùn)行過程中,廠房結(jié)構(gòu)在地震荷載及脈動壓力等作用下的動力特性一直是廠房研究關(guān)注的重點(diǎn)。因此,本文選擇對某實(shí)際燈泡貫流式水電站廠房結(jié)構(gòu)進(jìn)行研究,基于流固耦合分析水體對結(jié)構(gòu)自振特性以及地震響應(yīng)等的影響,并對結(jié)構(gòu)在脈動壓力作用下的動力響應(yīng)進(jìn)行了計(jì)算。論文主要研究內(nèi)容包括:(1)建立考慮廠房結(jié)構(gòu)—地基—水體在內(nèi)的流固耦合三維有限元模型,研究水體對廠房結(jié)構(gòu)自振特性的影響。結(jié)果表明水體使廠房結(jié)構(gòu)各階頻率值降低,附加質(zhì)量法考慮水體作用計(jì)算得到的頻率值相比流固耦合法考慮水體作用計(jì)算得到的頻率值略有減小,且各階振型也有所變化;進(jìn)行廠房結(jié)構(gòu)共振校核時需考慮水體作用,附加質(zhì)量法和流固耦合法得到的結(jié)果差異不大。(2)以流固耦合方式考慮水體計(jì)算得到了機(jī)組流道結(jié)構(gòu)在地震過程中的動水壓力分布,發(fā)現(xiàn)上游流道內(nèi)動水壓力大于下游尾水管的動水壓力。對比廠房結(jié)構(gòu)在不考慮水體、附加質(zhì)量法考慮水體作用及流固耦合法模擬水體三種方案下的地震響應(yīng),發(fā)現(xiàn)水體對廠房結(jié)構(gòu)大部分區(qū)域的動力響應(yīng)影響以增大為主,總體上附加質(zhì)量法產(chǎn)生的增幅要大于流固耦合法,此規(guī)律在位移和應(yīng)力兩個響應(yīng)量中表現(xiàn)較明顯,而在速度與加速度響應(yīng)中不夠明顯;水體對結(jié)構(gòu)速度與加速度響應(yīng)影響更復(fù)雜,對廠房結(jié)構(gòu)進(jìn)行抗震分析時需合理考慮水體作用。(3)分析水輪機(jī)流道CFD計(jì)算得到的流道脈動壓力分布規(guī)律,結(jié)合多個斷面的各測點(diǎn)的脈動壓力精確模擬整個流道脈動壓力場,采用時程法研究廠房在設(shè)計(jì)水頭不同機(jī)組出力工況下振動響應(yīng)的差異性。研究表明:隨著機(jī)組出力的減小,流道脈動壓力增大,廠房的振動位移、振動速度及振動加速度等響應(yīng)值也增大,但各響應(yīng)值均小于廠房振動標(biāo)準(zhǔn)的建議值;轉(zhuǎn)輪葉片頻率是引起廠房振動的主要頻率。(4)結(jié)合流道內(nèi)脈動壓力的分布,采用諧響應(yīng)法對流道進(jìn)行分區(qū)加載,對比最大出力工況下各響應(yīng)量與時程法的差異。結(jié)果表明諧響應(yīng)法計(jì)算得到的副廠房樓板各響應(yīng)均方根值大于時程法得到的結(jié)果,導(dǎo)葉與轉(zhuǎn)輪間區(qū)域及尾水管區(qū)域的脈動壓力在引起副廠房樓板振動響應(yīng)中占據(jù)了絕大部分作用。
[Abstract]:Bulb tubular hydropower station is generally river bed type, which is the most suitable way to develop low head hydraulic resources. Because of its high hydraulic efficiency, larger unit flow rate and higher unit rotational speed, small amount of civil engineering and quick investment, etc. It has been widely used in practical engineering at home and abroad. The power house of bulb tubular hydropower station is mostly a water-retaining powerhouse, which itself is a part of the water retaining structure of the hub, and the size of the runner of the unit is huge. The interaction between water and structure has a great influence on the structural characteristics of the powerhouse. During the operation of hydropower station, the dynamic characteristics of powerhouse structure under the action of seismic load and pulsating pressure have been the focus of attention. Therefore, this paper chooses to study the structure of a practical bulb tubular hydropower station powerhouse, based on fluid-solid coupling analysis of the impact of water on the natural vibration characteristics of the structure and seismic response, etc. The dynamic response of the structure under pulsating pressure is calculated. The main contents of this paper are as follows: (1) the fluid-solid coupling three-dimensional finite element model considering powerhouse structure, foundation and water body is established to study the influence of water body on the natural vibration characteristics of powerhouse structure. The results show that the frequency values of the powerhouse structure are reduced by water, and the frequencies calculated by the additional mass method considering the interaction of water body are slightly smaller than those calculated by the fluid-solid coupling method, and the vibration modes of each order are also changed. The effect of water body should be taken into account in the resonance checking of powerhouse structure, but there is no difference between the additional mass method and fluid-structure coupling method. (2) the hydrodynamic pressure distribution of unit runner structure during earthquake is obtained by considering the water body in fluid-solid coupling mode. It is found that the hydrodynamic pressure in the upstream channel is greater than that in the downstream draft pipe. Comparing the seismic response of the powerhouse structure under the three schemes without considering the water body, the additional mass method and the fluid-solid coupling method, it is found that the effect of water body on the dynamic response of most areas of the powerhouse structure is mainly increased. On the whole, the increase of the additional mass method is larger than that of the fluid-solid coupling method, which is obvious in the displacement and stress response, but not obvious in the velocity and acceleration response. The influence of water on structural velocity and acceleration response is more complex, so the water body action should be considered reasonably in seismic analysis of powerhouse structure. (3) the distribution law of fluctuating pressure of runner obtained by CFD calculation of hydraulic turbine runner is analyzed. The pulsating pressure field of the whole channel is accurately simulated by the pulsating pressure at various measuring points of several sections. The difference of vibration response of the powerhouse under different unit output conditions with different design head is studied by time-process method. The results show that with the decrease of generating force, the pulsating pressure of the runner increases, and the vibration displacement, velocity and acceleration of the powerhouse also increase, but each response value is less than the suggested value of the vibration standard of the powerhouse. The frequency of runner blade is the main frequency that causes the vibration of the powerhouse. (4) combined with the distribution of pulsating pressure in the channel, the harmonic response method is used to load the runner in different zones, and the difference between the response and the time-history method under the maximum output condition is compared. The results show that the root mean square (RMS) values of each response obtained by the harmonic response method are larger than those obtained by the time-history method. The pulsating pressure between the guide vane and the runner and the draft tube area plays an important role in the vibration response of the auxiliary workshop floor.
【學(xué)位授予單位】：武漢大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TV731
本文編號：2249866
[Abstract]:Bulb tubular hydropower station is generally river bed type, which is the most suitable way to develop low head hydraulic resources. Because of its high hydraulic efficiency, larger unit flow rate and higher unit rotational speed, small amount of civil engineering and quick investment, etc. It has been widely used in practical engineering at home and abroad. The power house of bulb tubular hydropower station is mostly a water-retaining powerhouse, which itself is a part of the water retaining structure of the hub, and the size of the runner of the unit is huge. The interaction between water and structure has a great influence on the structural characteristics of the powerhouse. During the operation of hydropower station, the dynamic characteristics of powerhouse structure under the action of seismic load and pulsating pressure have been the focus of attention. Therefore, this paper chooses to study the structure of a practical bulb tubular hydropower station powerhouse, based on fluid-solid coupling analysis of the impact of water on the natural vibration characteristics of the structure and seismic response, etc. The dynamic response of the structure under pulsating pressure is calculated. The main contents of this paper are as follows: (1) the fluid-solid coupling three-dimensional finite element model considering powerhouse structure, foundation and water body is established to study the influence of water body on the natural vibration characteristics of powerhouse structure. The results show that the frequency values of the powerhouse structure are reduced by water, and the frequencies calculated by the additional mass method considering the interaction of water body are slightly smaller than those calculated by the fluid-solid coupling method, and the vibration modes of each order are also changed. The effect of water body should be taken into account in the resonance checking of powerhouse structure, but there is no difference between the additional mass method and fluid-structure coupling method. (2) the hydrodynamic pressure distribution of unit runner structure during earthquake is obtained by considering the water body in fluid-solid coupling mode. It is found that the hydrodynamic pressure in the upstream channel is greater than that in the downstream draft pipe. Comparing the seismic response of the powerhouse structure under the three schemes without considering the water body, the additional mass method and the fluid-solid coupling method, it is found that the effect of water body on the dynamic response of most areas of the powerhouse structure is mainly increased. On the whole, the increase of the additional mass method is larger than that of the fluid-solid coupling method, which is obvious in the displacement and stress response, but not obvious in the velocity and acceleration response. The influence of water on structural velocity and acceleration response is more complex, so the water body action should be considered reasonably in seismic analysis of powerhouse structure. (3) the distribution law of fluctuating pressure of runner obtained by CFD calculation of hydraulic turbine runner is analyzed. The pulsating pressure field of the whole channel is accurately simulated by the pulsating pressure at various measuring points of several sections. The difference of vibration response of the powerhouse under different unit output conditions with different design head is studied by time-process method. The results show that with the decrease of generating force, the pulsating pressure of the runner increases, and the vibration displacement, velocity and acceleration of the powerhouse also increase, but each response value is less than the suggested value of the vibration standard of the powerhouse. The frequency of runner blade is the main frequency that causes the vibration of the powerhouse. (4) combined with the distribution of pulsating pressure in the channel, the harmonic response method is used to load the runner in different zones, and the difference between the response and the time-history method under the maximum output condition is compared. The results show that the root mean square (RMS) values of each response obtained by the harmonic response method are larger than those obtained by the time-history method. The pulsating pressure between the guide vane and the runner and the draft tube area plays an important role in the vibration response of the auxiliary workshop floor.
【學(xué)位授予單位】：武漢大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TV731
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