發(fā)布時(shí)間：2018-07-04 23:20

  本文選題：混流式水輪機(jī) + 計(jì)算流體力學(xué)��； 參考：《昆明理工大學(xué)》2014年碩士論文

【摘要】：我國水資源居世界首位,開發(fā)利用水資源一直是我國的重大課題。在“優(yōu)先發(fā)展水電”的方針背景下,我國水電建設(shè)發(fā)展迅速,水輪機(jī)朝著大容量、高水頭、高比轉(zhuǎn)速方面發(fā)展,對(duì)水力機(jī)組的設(shè)計(jì)、制造和科學(xué)研究也提出了新的要求。 影響水輪機(jī)機(jī)組性能的三項(xiàng)指標(biāo)為效率、穩(wěn)定性和空化性能。目前,水輪機(jī)的效率最高可達(dá)95%,而空化問題歷來是水力機(jī)械領(lǐng)域的難題之一,水輪機(jī)運(yùn)行的不穩(wěn)定性也隨著機(jī)組水頭和容量的提高而逐漸顯現(xiàn)出來。在水輪機(jī)運(yùn)行的過程中,空化會(huì)使其過流部件產(chǎn)生空蝕破壞,從而產(chǎn)生噪聲和振動(dòng),嚴(yán)重影響機(jī)組的效率和運(yùn)行的穩(wěn)定性。因此,水輪機(jī)的空化空蝕問題成為水輪機(jī)領(lǐng)域中人們非常關(guān)心的基本問題之一。轉(zhuǎn)輪是水輪機(jī)的核心過流部件,其對(duì)水輪機(jī)機(jī)組的性能起著決定性的作用,因此,對(duì)水輪機(jī)轉(zhuǎn)輪空化問題的研究更應(yīng)值得關(guān)注,也是提高水輪機(jī)性能必須認(rèn)真研究解決的重要課題。 隨著CFD的發(fā)展和計(jì)算機(jī)水平的提高,數(shù)值模擬成為研究水輪機(jī)內(nèi)部流動(dòng)的一種重要手段。通過低成本、短周期的數(shù)值模擬對(duì)水輪機(jī)進(jìn)行分析和工程設(shè)計(jì)對(duì)于提高水輪機(jī)運(yùn)行的穩(wěn)定性和經(jīng)濟(jì)性具有重要作用。 本文以計(jì)算流體力學(xué)知識(shí)為基礎(chǔ),以通用性CFD軟件FLUENT為工具,先采用基于Reynolds平均法的RNG κ-ε兩方程湍流模型模擬了帶副葉片混流式水輪機(jī)轉(zhuǎn)輪內(nèi)部的單相三維湍流流動(dòng)情況,得到該水輪機(jī)轉(zhuǎn)輪在不同流量工況下的三維流場分布后,再以單相流動(dòng)計(jì)算結(jié)果為計(jì)算初值,補(bǔ)充上混合流體無滑移兩相流模型,模擬了該水輪機(jī)轉(zhuǎn)輪內(nèi)部的空化流動(dòng)情況,得到了該型水輪機(jī)轉(zhuǎn)輪在不同流量工況下的空化流場分布,可以給預(yù)測、改善水輪機(jī)空化性能提供依據(jù),對(duì)于提高水輪機(jī)效率和穩(wěn)定性、改善水輪機(jī)的綜合水力性能具有重要意義。本文具體完成的工作如下： 1.根據(jù)帶副葉片混流式水輪機(jī)HLA351的基本單位參數(shù),利用實(shí)體建模工具Pro/ENGINEER軟件對(duì)該水輪機(jī)轉(zhuǎn)輪進(jìn)行了三維幾何建模,然后利用前處理工具GAMBIT對(duì)轉(zhuǎn)輪的幾何模型進(jìn)行了網(wǎng)格劃分、設(shè)置邊界類型等操作,得到了可以用于CFD計(jì)算的物理對(duì)象。 2.利用仿真工具FLUENT對(duì)帶副葉片混流式水輪機(jī)轉(zhuǎn)輪進(jìn)行了內(nèi)部單相流場的模擬,得到了該水輪機(jī)在不同流量工況下的三維流場分布。 3.以單相流動(dòng)計(jì)算的結(jié)果作為初始條件,對(duì)上述水輪機(jī)進(jìn)行了內(nèi)部空化流場的模擬,得到了該水輪機(jī)在不同流量工況下的空化流場分布。 4.對(duì)單相流動(dòng)和空化流動(dòng)的結(jié)果進(jìn)行后處理,總結(jié)分析了該水輪機(jī)在不同流量工況下的空化流動(dòng)。
[Abstract]:Water resources in our country occupy the first place in the world, and exploitation and utilization of water resources has been a major issue in our country. Under the background of the policy of "giving priority to the development of hydropower", the construction of hydropower in China is developing rapidly, and the turbine is developing towards the aspects of large capacity, high head and high specific speed. New requirements are put forward for the design, manufacture and scientific research of hydraulic units. The efficiency, stability and cavitation performance are the three indexes that affect the performance of the turbine unit. At present, the efficiency of turbine is up to 95%, and the cavitation problem is always one of the difficult problems in the field of hydraulic machinery. The instability of turbine operation gradually appears with the increase of water head and capacity of turbine. In the process of turbine operation cavitation will lead to cavitation damage of its overflowing parts resulting in noise and vibration which seriously affects the efficiency and stability of the unit. Therefore, cavitation erosion has become one of the most important problems in turbine field. The runner is the core overflowing part of the turbine, which plays a decisive role in the performance of the turbine unit. Therefore, the study on the cavitation of the turbine runner should be paid more attention to. It is also an important subject that must be studied and solved to improve the performance of hydraulic turbine. With the development of CFD and the improvement of computer level, numerical simulation has become an important means to study the internal flow of hydraulic turbines. The analysis and engineering design of hydraulic turbine by low cost and short period numerical simulation play an important role in improving the stability and economy of turbine operation. Based on the knowledge of computational fluid mechanics and using CFD software fluent as a tool, the turbulent model of RNG 魏-蔚 two-equation turbulence based on Reynolds averaging method is used to simulate the single-phase three-dimensional turbulent flow in the runner of Francis turbine with auxiliary blades. After the three-dimensional flow field distribution of the turbine runner under different flow conditions is obtained, the cavitation flow inside the turbine runner is simulated by using the calculation results of single-phase flow as the initial value and supplementing the non-slip two-phase flow model of the upper mixed fluid. The cavitation flow field distribution of the turbine runner under different flow conditions is obtained, which can provide the basis for predicting and improving the cavitation performance of the turbine, and can improve the efficiency and stability of the turbine. It is of great significance to improve the comprehensive hydraulic performance of hydraulic turbines. The work accomplished in this paper is as follows: 1. According to the basic unit parameters of HLA351 of Francis turbine with auxiliary blades, the 3D geometric model of the turbine runner is modeled by using the solid modeling tool Pro-ENGINEER, and then the geometric model of the runner is meshed by the pre-processing tool gambit. Set the boundary type and other operations, get a CFD can be used to calculate the physical object. 2. 2. The simulation tool fluent is used to simulate the internal single-phase flow field of Francis turbine runner with auxiliary vane, and the three-dimensional flow field distribution of the turbine under different flow conditions is obtained. Taking the results of single-phase flow calculation as initial conditions, the cavitation flow field of the turbine is simulated, and the cavitation flow field distribution of the turbine under different flow conditions is obtained. The results of single phase flow and cavitation flow are processed, and the cavitation flow of the turbine under different flow conditions is summarized and analyzed.
【學(xué)位授予單位】：昆明理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TK733.1

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