本文選題：水斗式水輪機(jī) + 過渡過程　； 參考：《武漢大學(xué)》2017年碩士論文

【摘要】：隨著沖擊式水輪機(jī)比轉(zhuǎn)速、尺寸、單機(jī)容量不斷增大,大量新型材料的使用導(dǎo)致水輪機(jī)的相對(duì)剛度降低,高速射流的沖擊力作用以及轉(zhuǎn)輪自身的高速旋轉(zhuǎn)所引起的結(jié)構(gòu)振動(dòng)、水斗表面局部損壞、水斗整體斷裂問題十分突出,嚴(yán)重影響到水輪機(jī)運(yùn)行的安全和穩(wěn)定,引起了國內(nèi)外廣大研究人員的關(guān)注。目前,國內(nèi)外關(guān)于沖擊式水輪機(jī)轉(zhuǎn)輪結(jié)構(gòu)力學(xué)性能的研究欠深入,一般選取某一瞬時(shí)狀態(tài)進(jìn)行靜力分析,然后以此為基礎(chǔ)進(jìn)行轉(zhuǎn)輪結(jié)構(gòu)的模態(tài)分析,在多噴嘴水斗式水輪機(jī)結(jié)構(gòu)方面的研究較少。本文在前人研究的基礎(chǔ)上,采用流固耦合數(shù)值模擬方法,首先研究了沖擊式水輪機(jī)在啟動(dòng)工況、額定運(yùn)行工況、飛逸工況的水力特性和結(jié)構(gòu)特性;然后針對(duì)多噴嘴水斗式水輪機(jī)進(jìn)行了流固耦合分析,并對(duì)轉(zhuǎn)輪結(jié)構(gòu)進(jìn)行模態(tài)分析。這是對(duì)沖擊式水輪機(jī)轉(zhuǎn)輪結(jié)構(gòu)動(dòng)力學(xué)特性研究的一種探索和嘗試。本文以CJA475-W-83沖擊式水輪機(jī)轉(zhuǎn)輪結(jié)構(gòu)為研究對(duì)象,在給定水輪機(jī)水力條件下進(jìn)行轉(zhuǎn)輪三維建模、流場分析、靜力分析,在此基礎(chǔ)上,探究沖擊式水輪機(jī)在不同工作狀態(tài)下的振動(dòng)特性:(1)轉(zhuǎn)輪流場分析�？紤]水氣二相流作用,在Fluent軟件中建立轉(zhuǎn)輪流場三維瞬態(tài)分析模型,進(jìn)行流體流態(tài)計(jì)算,得到額定運(yùn)行工況、啟動(dòng)過程、飛逸過程下的流態(tài)和壓力分布規(guī)律;然后計(jì)算多噴嘴水斗式水輪機(jī)穩(wěn)定運(yùn)行工況下不同水頭、不同開度情況下的水力特性,為之后轉(zhuǎn)輪結(jié)構(gòu)有限元分析提供荷載依據(jù)。(2)轉(zhuǎn)輪結(jié)構(gòu)靜力分析。運(yùn)用單向流固耦合的方式,提取流場分析的結(jié)果作為轉(zhuǎn)輪靜力分析的荷載,利用Ansys Workbench中的Static Structural模塊對(duì)轉(zhuǎn)輪結(jié)構(gòu)進(jìn)行靜力分析,得到啟動(dòng)、額定、飛逸工況下轉(zhuǎn)輪結(jié)構(gòu)的應(yīng)力、位移分布規(guī)律,為之后工作狀態(tài)下的結(jié)構(gòu)振動(dòng)模態(tài)分析提供應(yīng)力依據(jù)。(3)轉(zhuǎn)輪結(jié)構(gòu)模態(tài)分析。在靜力分析的基礎(chǔ)上,對(duì)轉(zhuǎn)輪結(jié)構(gòu)進(jìn)行自由狀態(tài)、約束狀態(tài)和工作狀態(tài)下的模態(tài)分析,得到轉(zhuǎn)輪靜頻、動(dòng)頻以及各階振型。通過分析頻率,得到了轉(zhuǎn)輪結(jié)構(gòu)的固有頻域范圍;通過分析振型,得到了轉(zhuǎn)輪結(jié)構(gòu)的振動(dòng)規(guī)律;同時(shí),探究了轉(zhuǎn)輪轉(zhuǎn)速和射流沖擊力對(duì)沖擊式水輪機(jī)轉(zhuǎn)輪結(jié)構(gòu)模態(tài)的影響,結(jié)合沖擊式水輪機(jī)的運(yùn)行工況判斷轉(zhuǎn)輪結(jié)構(gòu)共振的可能性。本文模擬了沖擊式水輪機(jī)過渡過程中的水力特性和結(jié)構(gòu)動(dòng)力特性,并針對(duì)多噴嘴水斗式水輪機(jī)進(jìn)行了分析,所得結(jié)論有助于指導(dǎo)水輪機(jī)設(shè)計(jì)和運(yùn)行,且對(duì)實(shí)際工程有參考價(jià)值。
[Abstract]:With the increase of the speed, size and single machine capacity of the impact turbine, the use of a large number of new materials leads to the reduction of the relative stiffness of the turbine, the impact of the high speed jet and the high-speed rotation of the wheel, and the local damage to the surface of the bucket, and the problem of the overall fracture of the bucket is very prominent, which seriously affects the water. The safety and stability of the turbine operation has aroused the attention of the large number of researchers at home and abroad. At present, the research on the mechanical properties of the shock turbine runner is not deep, and the static analysis is generally selected for a certain instantaneous state, and then on the basis of the modal analysis of the rotary wheel structure, in the multi nozzle bucket turbine junction. In this paper, on the basis of the previous research, the hydraulic and solid coupling numerical simulation method is used to study the hydraulic and structural characteristics of the impact turbine at the starting, rated operating and flight conditions, and then the fluid solid coupling analysis is carried out for the multi nozzle water turbine and the structure of the runner is carried out. Modal analysis. This is a kind of exploration and attempt to study the dynamic characteristics of the structure of the shock turbine runner. This paper takes the structure of the CJA475-W-83 shock turbine runner as the research object. The three dimensional modeling, flow field analysis and static analysis are carried out under the hydraulic condition of a given hydraulic turbine. On this basis, the impact hydraulic turbine is studied in different ways. The vibration characteristics of the working state are: (1) the analysis of the flow field of the runner. Considering the effect of two phase flow of water and gas, the three-dimensional transient analysis model of the runner flow field is established in the Fluent software, the flow state is calculated, the flow state and pressure distribution under the rated operating condition, the starting process, the runaway process and the pressure distribution are obtained, and then the steady transportation of the multi nozzle water turbine is calculated. The hydraulic characteristics of different water heads and different opening conditions are provided for the finite element analysis of the rear wheel structure. (2) static analysis of the structure of the runner. Using the unidirectional fluid solid coupling method, the result of the analysis of the flow field is extracted as the load of the wheel static analysis, and the Static Structural module in the Ansys Workbench is used for the wheel. The structure is static analysis, and the stress and displacement distribution law of the runner structure in the starting, rated and flying conditions are obtained. (3) the modal analysis of the structural vibration of the runner. On the basis of static analysis, the free state, the constraint state and the working state of the wheel structure are carried out. The static frequency, dynamic frequency and various modes of the runner are obtained. By analyzing the frequency, the natural frequency range of the wheel structure is obtained. By analyzing the vibration mode, the vibration law of the wheel structure is obtained. At the same time, the influence of the rotating wheel speed and the impingement force on the structure mode of the shock turbine runner is explored, and the transport of the shock turbine is combined. This paper simulates the hydraulic and structural dynamic characteristics of the hydraulic turbine during the transition process, and analyzes the multi nozzle water turbine. The conclusions are helpful to guide the design and operation of the turbine, and have a reference value to the actual project.
【學(xué)位授予單位】：武漢大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TV734.1

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