發(fā)布時(shí)間：2018-11-26 19:05

【摘要】：迄今為止,關(guān)于含沙河流中運(yùn)行的水輪機(jī)泥沙磨損破壞機(jī)理的研究取得了很大的進(jìn)步,但還不十分成熟。 常規(guī)混流式水輪機(jī)在含沙河流運(yùn)行過(guò)程中,水輪機(jī)的空蝕和磨損破壞非常嚴(yán)重,特別是在高水頭狀態(tài)下運(yùn)行,情況更為嚴(yán)重,水輪機(jī)的空蝕和磨損破壞已是水電站安全運(yùn)行的一個(gè)重要問(wèn)題。事實(shí)證明,長(zhǎng)短葉片混流式水輪機(jī)能夠減輕空蝕破壞及泥沙磨損,但問(wèn)題并沒(méi)有得到徹底解決,故需要對(duì)長(zhǎng)短葉片混流式水輪機(jī)內(nèi)部固液兩相流動(dòng)進(jìn)行研究,探討水輪機(jī)內(nèi)部沙水流場(chǎng)的流動(dòng)機(jī)理,為長(zhǎng)短葉片水輪機(jī)設(shè)計(jì)提供參考。 本文將其水輪機(jī)各過(guò)流部件作為整體來(lái)考慮,基于N-S方程,分別對(duì)其水輪機(jī)內(nèi)的清水及沙水流動(dòng)進(jìn)行數(shù)值計(jì)算。研究的成果如下: 一、根據(jù)一具體水輪機(jī)的水力設(shè)計(jì)技術(shù)參數(shù),采用Unigraphics軟件分別對(duì)水輪機(jī)引水部件、導(dǎo)水機(jī)構(gòu)、轉(zhuǎn)輪及尾水管進(jìn)行三維幾何建模。并將建好的各過(guò)流部件三維模型導(dǎo)入Gambit軟件中,并對(duì)其依次進(jìn)行網(wǎng)格劃分及指定邊界類(lèi)型和區(qū)域類(lèi)型; 二、分別對(duì)清水中大流量工況、最優(yōu)工況、小流量工況下水輪機(jī)內(nèi)部流動(dòng)進(jìn)行數(shù)值計(jì)算; 三、分別對(duì)沙水中的顆粒體積濃度和直徑一定流量不同,顆粒體積濃度和流量一定顆粒直徑不同,顆粒直徑和流量一定顆粒體積濃度不同的情況下水輪機(jī)內(nèi)部流動(dòng)進(jìn)行數(shù)值計(jì)算;通過(guò)對(duì)清水和沙水的數(shù)值計(jì)算結(jié)果的對(duì)比分析,獲得了長(zhǎng)短葉片水輪機(jī)各過(guò)流部件的泥沙磨損和空蝕破壞規(guī)律。計(jì)算結(jié)果與實(shí)際電站在運(yùn)行過(guò)程中發(fā)生的情況基本吻合。
[Abstract]:So far, great progress has been made in the study of sediment wear failure mechanism of turbine running in a sandy river, but it is not very mature. The cavitation erosion and wear damage of conventional Francis turbine is very serious during the operation of the sand bearing river, especially in the high head condition, the situation is more serious. Cavitation erosion and wear and tear of hydraulic turbines have become an important problem in the safe operation of hydropower stations. It has been proved that long and short vane Francis turbine can reduce cavitation erosion and sediment wear, but the problem has not been completely solved, so it is necessary to study the solid-liquid two-phase flow in the long and short blade Francis turbine. The flow mechanism of sand flow field in turbine is discussed, which provides a reference for the design of long and short blade turbine. Based on N-S equation, the flow of clean water and sand water in the turbine is numerically calculated by considering the flow components of the turbine as a whole. The results are as follows: firstly, according to the hydraulic design technical parameters of a specific hydraulic turbine, Unigraphics software is used to model the three dimensional geometry of the turbine diversion unit, water guide mechanism, runner and draft tube respectively. The 3D model of the constructed flow components is imported into the Gambit software, and it is meshed in turn, and the boundary type and the area type are specified. Secondly, the internal flow of the turbine is numerically calculated under the conditions of large flow rate, optimal working condition and small flow rate. Third, the particle volume concentration and diameter of sand water are different, and the particle volume concentration and flow rate are different. When the particle diameter and flow rate are different, the flow inside the turbine is numerically calculated. By comparing and analyzing the numerical results of clear water and sand water, the rules of sediment wear and cavitation erosion of each flow part of long and short blade turbine are obtained. The calculated results are in good agreement with the actual operation of the power station.
【學(xué)位授予單位】：西華大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2011
【分類(lèi)號(hào)】：TH311

【引證文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前1條

1 劉爭(zhēng)光;長(zhǎng)短葉片混流式水輪機(jī)內(nèi)部固液兩相流動(dòng)數(shù)值模擬[D];西華大學(xué);2012年

，

本文編號(hào)：2359364