本文選題：水泵水輪機(jī) + 開停機(jī)過程�。� 參考：《西安理工大學(xué)》2017年碩士論文

【摘要】：水泵水輪機(jī)在運(yùn)行過程中工況轉(zhuǎn)換頻繁,在工況轉(zhuǎn)換過程中保證機(jī)組穩(wěn)定運(yùn)行是至關(guān)重要的。近年來(lái),在某些抽水蓄能電站水泵水輪機(jī)開停機(jī)過程中,當(dāng)活動(dòng)導(dǎo)葉開度很小時(shí),導(dǎo)水機(jī)構(gòu)會(huì)出現(xiàn)振動(dòng)和異常噪音。為了找出引起這種不穩(wěn)定現(xiàn)象的原因,論文對(duì)水泵水輪機(jī)泵工況開停機(jī)過程小開度區(qū)出現(xiàn)的不穩(wěn)定現(xiàn)象進(jìn)行了深入研究。論文以天荒坪電站水泵水輪機(jī)為研究對(duì)象,建立了從蝸殼進(jìn)口至尾水管出口的三維全流道幾何模型,以電站全系統(tǒng)過渡過程計(jì)算結(jié)果為邊界條件,運(yùn)用動(dòng)網(wǎng)格技術(shù)對(duì)其開停機(jī)過程進(jìn)行了詳細(xì)的研究,定量分析了開停機(jī)過程中特殊流態(tài)的形成機(jī)理和流動(dòng)規(guī)律。研究表明,導(dǎo)葉間的主流會(huì)隨著開度的變化在兩種流態(tài)之間偏轉(zhuǎn)。即在常規(guī)流態(tài)(I型流態(tài))與特殊流態(tài)(II型流態(tài))之間變化。在開機(jī)過程中,當(dāng)開度非常小時(shí),主流呈現(xiàn)II型流態(tài),隨著開度的增大,主流開始從II型流態(tài)向I型流態(tài)偏轉(zhuǎn),當(dāng)開度繼續(xù)增大時(shí),主流呈現(xiàn)I型流態(tài)。在停機(jī)過程中,當(dāng)開度較大的時(shí)候,主流呈現(xiàn)I型流態(tài),隨著開度減小,主流開始從I型流態(tài)向II型流態(tài)偏轉(zhuǎn),當(dāng)開度繼續(xù)減小,主流呈現(xiàn)II型流態(tài)。在周向不同導(dǎo)葉之間,流態(tài)偏轉(zhuǎn)的開度和偏轉(zhuǎn)時(shí)間略有不同,但趨勢(shì)一致。開機(jī)過程和停機(jī)過程流動(dòng)的偏轉(zhuǎn)過程也有差異,停機(jī)過程流動(dòng)偏轉(zhuǎn)持續(xù)時(shí)間長(zhǎng),主流在偏轉(zhuǎn)過程中會(huì)往復(fù)擺動(dòng)。主流的偏轉(zhuǎn)會(huì)引起導(dǎo)葉周圍流場(chǎng)的劇烈變化,使得活動(dòng)導(dǎo)葉水力矩發(fā)生突變,引起導(dǎo)水機(jī)構(gòu)產(chǎn)生異常振動(dòng)和噪音,研究結(jié)果與電站開停機(jī)過程小開度區(qū)實(shí)際運(yùn)行結(jié)果相吻合,揭示了水泵水輪機(jī)開停機(jī)過程中導(dǎo)水機(jī)構(gòu)產(chǎn)生振動(dòng)的原因。通過分析活動(dòng)導(dǎo)葉在開停機(jī)過程中的應(yīng)力變化規(guī)律,闡明了水泵水輪機(jī)泵工況開停機(jī)過程中小開度區(qū)出現(xiàn)的不穩(wěn)定誘因,結(jié)果表明:導(dǎo)葉最大靜應(yīng)力發(fā)生在導(dǎo)葉端面與軸頸相接處,主流流態(tài)的偏轉(zhuǎn)會(huì)使活動(dòng)導(dǎo)葉的內(nèi)部應(yīng)力發(fā)生劇烈變化,引起機(jī)組的不穩(wěn)定。
[Abstract]:The operating conditions of pump turbines change frequently during operation, so it is very important to ensure the stable operation of water pump turbines. In recent years, in some pumped storage power stations, the vibration and abnormal noise of water guide mechanism will appear when the active guide vane is very small during the opening and shutdown of pump turbine. In order to find out the causes of the instability, this paper deeply studies the instability in the small opening and down zone during the pump operating condition. Taking the pump turbine of Tianhuangping Hydropower Station as the research object, a three-dimensional full-channel geometric model from the inlet of the volute to the outlet of the draft pipe is established. The results of the whole system transition process of the power station are taken as the boundary conditions. The dynamic grid technology is used to study the on-off process in detail, and the formation mechanism and flow law of the special flow state in the on-off process are quantitatively analyzed. It is shown that the mainstream of the guide vane will deflect between the two flow states with the change of opening. That is to say, the variation between the normal flow pattern and the special flow state is between the normal flow mode and the special flow state. In the process of start-up, when the opening is very small, the mainstream presents type II flow state. With the increase of opening degree, the mainstream begins to deflect from type II flow state to mode I flow state, and when the opening degree continues to increase, the mainstream presents mode I flow state. In the process of downtime, when the opening degree is large, the mainstream presents mode I flow state. With the decrease of opening degree, the mainstream begins to deflect from mode I flow state to type II flow state, and when the opening degree continues to decrease, the mainstream presents type II flow state. The opening degree and the deflection time of the flow state deflection are slightly different between the circumferential guide vane, but the trend is the same. There are also differences in the flow deflection process between the start-up process and the shutdown process. The flow deflection duration of the shutdown process is long and the mainstream will swing back and forth during the deflection process. The deflection of the mainstream will cause drastic changes in the flow field around the guide vane, causing a sudden change in the water torque of the active guide vane, resulting in abnormal vibration and noise of the water-conducting mechanism. The results of the study are in agreement with the actual operation results of the small opening and closing zone during the power station's opening and shutdown process. The cause of the vibration of the guide water mechanism during the opening and stopping process of the pump turbine is revealed. Based on the analysis of the stress variation of the guide vane during the process of opening and stopping, the unstable inducement of the small open and down zone in the operating condition of pump turbine pump is expounded. The results show that the maximum static stress of the guide vane occurs at the junction of the end face of the guide vane and the shaft neck, and the deflection of the main flow state will make the internal stress of the moving guide vane change dramatically and cause the instability of the unit.
【學(xué)位授予單位】：西安理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TV743;TV734

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 李文鋒;馮建軍;羅興，

本文編號(hào)：1954602