發(fā)布時(shí)間：2018-03-25 07:38

  本文選題：水力機(jī)械　切入點(diǎn)：CFD　出處：《哈爾濱工業(yè)大學(xué)》2014年碩士論文

【摘要】：我國西部高水頭水力資源的蘊(yùn)含量非常豐富，沖擊式水輪機(jī)具有適應(yīng)高水頭運(yùn)行的特點(diǎn)，，是高水頭水力開發(fā)必不可少的機(jī)型。然而與反擊式水輪機(jī)已經(jīng)非常成熟的技術(shù)相比，我國對沖擊式水輪機(jī)的研究可以說才剛剛起步。沖擊式水輪機(jī)內(nèi)部的流動(dòng)要比反擊式水輪機(jī)內(nèi)部流動(dòng)復(fù)雜很多，因?yàn)槠鋬?nèi)部流動(dòng)是三維非定常的氣液兩相流流動(dòng)，分析其流動(dòng)特點(diǎn)時(shí)，不僅要考慮氣體相與液體相之間的相互作用，還要考慮射流與射流之間相互干涉、射流與轉(zhuǎn)輪之間相互干涉等很多不良流動(dòng)現(xiàn)象，這些不良流動(dòng)現(xiàn)象會(huì)很大的降低水輪機(jī)的出力和效率，也會(huì)造成水輪機(jī)機(jī)組的不穩(wěn)定，因此對沖擊式水輪機(jī)內(nèi)部流動(dòng)狀態(tài)進(jìn)行分析，研究其內(nèi)部的存在的各種不良流動(dòng)現(xiàn)象就顯得特別重要。 為實(shí)現(xiàn)對沖擊式水輪機(jī)內(nèi)部流動(dòng)進(jìn)行分析，本文中對某一在運(yùn)水電站的水斗式水輪機(jī)原型內(nèi)部流動(dòng)進(jìn)行了數(shù)值模擬，本文研究的主要內(nèi)容如下： 1.對沖擊式水輪機(jī)的導(dǎo)水部件配水管進(jìn)行數(shù)值模擬，分析其內(nèi)部的流動(dòng)不均勻現(xiàn)象和流動(dòng)損失，并對噴嘴內(nèi)流場進(jìn)行數(shù)值模擬，得到此噴嘴中噴針行程與噴嘴流量的關(guān)系。 2.通過對沖擊式水輪機(jī)轉(zhuǎn)輪內(nèi)部兩相流流動(dòng)進(jìn)行數(shù)值模擬，對不同時(shí)刻同一水斗內(nèi)的流動(dòng)狀態(tài)進(jìn)行了分析，對同一時(shí)刻轉(zhuǎn)輪中受兩射流作用的不同水斗內(nèi)流場進(jìn)行了分析。 3.通過對沖擊式水輪機(jī)轉(zhuǎn)輪內(nèi)部兩相流流動(dòng)全過程的數(shù)值模擬，找到本文研究水輪機(jī)內(nèi)部存在的三種不良流動(dòng)現(xiàn)象，并給予合理的解釋，最后針對每一種不良流動(dòng)給出合理的解決方案，并分析各種方案的可行性。 結(jié)果表明，配水管中支路突然轉(zhuǎn)折是造成配水管中流動(dòng)不均勻的原因，噴嘴內(nèi)絕大部分流動(dòng)損失產(chǎn)生在噴嘴出口的薄壁小孔口出流處，數(shù)值計(jì)算的噴針行程與流量關(guān)系曲線比理論值偏低，但大體趨勢相同。本文研究沖擊式水輪機(jī)內(nèi)部一共存在三種不良流動(dòng)現(xiàn)象，分別是兩射流同時(shí)流入流出同一水斗的不良流動(dòng)，出水邊流出流體與下一水斗背面干涉的不良流動(dòng)和背面打水現(xiàn)象，這三種不良流動(dòng)現(xiàn)象均可以通過適當(dāng)改型或?qū)λ啓C(jī)轉(zhuǎn)輪重新選型來避免。
[Abstract]:The high head hydraulic resources in the west of China are very rich in content. The impact turbine has the characteristics of adapting to the high head operation and is an indispensable model for the high head hydraulic development. However, compared with the counterattack turbine, it is very mature. The research on impingement turbine in our country is just beginning. The internal flow of impingement turbine is much more complicated than that of counterattack turbine, because the internal flow is three dimensional unsteady gas-liquid two-phase flow. When analyzing its flow characteristics, it is necessary to consider not only the interaction between gas phase and liquid phase, but also the interference between jet and jet, interference between jet and runner, and so on. These bad flow phenomena will greatly reduce the turbine productivity and efficiency, but also lead to the turbine unit instability, so the impact turbine internal flow state analysis, It is particularly important to study the existence of various undesirable flow phenomena within it. In order to analyze the internal flow of impingement turbine, a numerical simulation of the flow inside the prototype of a hydraulic bucket turbine is carried out in this paper. The main contents of this paper are as follows:. 1. Numerical simulation is carried out on the water distribution pipe of the impinging turbine, and the inhomogeneity and loss of the flow inside the nozzle are analyzed, and the relationship between the injection stroke and the flow rate of the nozzle is obtained by numerical simulation of the flow field inside the nozzle. 2. Through the numerical simulation of the two-phase flow in the impinging turbine runner, the flow state in the same bucket at the same time is analyzed, and the flow field of the different water hoppers acting on the two jets in the runner at the same time is analyzed. 3. Through the numerical simulation of the whole process of the two-phase flow in the impact-type turbine runner, it is found that there are three kinds of bad flow phenomena in the turbine, and the reasonable explanation is given. Finally, a reasonable solution for each kind of bad flow is given, and the feasibility of each scheme is analyzed. The results show that the sudden turning of the branch in the distribution pipe is the cause of the uneven flow in the distribution pipe, and most of the flow losses in the nozzle occur at the outlet of the thin wall orifice of the nozzle. The calculated curve of the relationship between the injection stroke and the flow rate is lower than the theoretical value, but the general trend is the same. In this paper, there are three kinds of bad flow phenomena in the impingement turbine. Two jets flow simultaneously into and out the same water hopper, the bad flow of the outflow fluid from the water side interferes with the back of the next bucket, and the backside water pumping phenomenon, These three bad flow phenomena can be avoided by proper modification or re-selection of turbine runner.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TK735

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本文編號(hào)：1662152