本文選題：蒸汽疏水閥門　切入點(diǎn)：泄漏　出處：《長沙理工大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：火電廠閥門泄漏將會(huì)降低整個(gè)發(fā)電機(jī)組的整體效率,甚至可能會(huì)直接威脅人員安全和機(jī)組運(yùn)行的安全性。目前,診斷閥門泄漏的方法很多,但是這些方法都有一定的局限性,在火電廠復(fù)雜的環(huán)境中很難診斷出閥門的早期泄漏故障。因此,基于疏水管道溫度場研究閥門泄漏故障具有重要的理論價(jià)值和良好的工程應(yīng)用前景。當(dāng)閥門發(fā)生泄漏時(shí),閥前管壁溫度也會(huì)相應(yīng)的變化,因而閥前管壁溫度可以用來作為檢測閥門是否發(fā)生泄漏的診斷特征參數(shù)。本文采用理論分析、數(shù)值模擬和工程實(shí)例驗(yàn)證相結(jié)合的方法,對(duì)基于疏水管道溫度場分布檢測的檢漏方法進(jìn)行了研究分析,從而得出火電廠疏水閥門泄漏檢測新方法。首先,本文將疏水管道劃分成若干微元段控制體,建立圓筒壁傳熱模型。依據(jù)圓筒壁傳熱理論建立管道在不同閥門泄漏工況下的溫度場計(jì)算模型。然后,以閥門未漏與閥門泄漏的兩個(gè)診斷模型作為依據(jù),建立了相對(duì)應(yīng)的數(shù)學(xué)模型,并從中提煉出了管壁溫度計(jì)算程序所需要的邏輯程序框圖,在此基礎(chǔ)上,編寫了閥前管壁溫度計(jì)算軟件。與此同時(shí),為了有效解決水蒸汽物性參數(shù)的計(jì)算精度,本文對(duì)水蒸汽狀態(tài)方程和IAPWS-IF97的計(jì)算精度進(jìn)行了分析,最終選擇了IAPWS-IF97作為水蒸汽的物性參數(shù)的計(jì)算公式,在此基礎(chǔ)上開發(fā)出了疏水管道管壁溫度計(jì)算軟件。最后,本文探索出一種火電廠蒸汽疏水閥門泄漏診斷新方法。該方法分兩步對(duì)閥門進(jìn)行泄漏故障進(jìn)行診斷。第一步為定性診斷,通過疏水管道管壁溫度計(jì)算軟件計(jì)算出閥門未泄露時(shí)的管壁溫度。管壁溫度實(shí)測值低于此溫度,判定閥門未發(fā)生泄漏。如果高于此溫度,進(jìn)行第二步定量診斷。通過對(duì)火電廠疏水管道在不同閥門泄漏工況下的溫度場分布進(jìn)行大量數(shù)值模擬計(jì)算,得出疏水管道壁溫度與泄漏量、管道內(nèi)徑、保溫層厚度等因素之間的變化關(guān)系,采用數(shù)學(xué)建模方法,把數(shù)值模擬所得出的數(shù)據(jù)擬合成定量計(jì)算公式,利用該計(jì)算公式實(shí)現(xiàn)閥門泄漏定量診斷。
[Abstract]:Valve leakage in thermal power plants will reduce the overall efficiency of the whole generator set, and may even directly threaten the safety of personnel and operation of the unit. At present, there are many methods to diagnose valve leakage, but these methods have some limitations. It is very difficult to diagnose the early leakage fault of valve in the complex environment of thermal power plant. Therefore, it is of great theoretical value and good engineering application prospect to study valve leakage fault based on the temperature field of drain pipe. The temperature of the front wall of the valve can be used as the diagnostic characteristic parameter to detect the leakage of the valve. The method of combining theoretical analysis, numerical simulation and engineering example is used in this paper. The leak detection method based on temperature field distribution of hydrophobic pipeline is studied and analyzed, and a new method for leak detection of drain valve door in thermal power plant is obtained. Firstly, the hydrophobic pipeline is divided into several microelement control bodies. The heat transfer model of cylinder wall is established. According to the theory of heat transfer of cylinder wall, the calculation model of temperature field of pipeline under different valve leakage conditions is established. Then, two diagnostic models of valve leakage and valve leakage are taken as the basis. The corresponding mathematical model is established, and the logical program block diagram of pipe wall temperature calculation program is abstracted from it. On the basis of this, the calculation software of pipe wall temperature in front of valve is compiled. At the same time, In order to effectively solve the calculation accuracy of the physical parameters of water vapor, the equation of state of water vapor and the calculation accuracy of IAPWS-IF97 are analyzed in this paper. Finally, IAPWS-IF97 is chosen as the calculation formula of the physical parameters of water vapor. On this basis, the software for calculating the wall temperature of the hydrophobic pipe is developed. Finally, In this paper, a new method of leak diagnosis of steam trap valve door in thermal power plant is explored. The method is divided into two steps to diagnose the leakage fault of valve. The first step is qualitative diagnosis. The wall temperature of the drain pipe is calculated by the software of pipe wall temperature calculation of the drain pipe. The measured value of the wall temperature of the pipe wall is lower than this temperature, and it is determined that there is no leakage of the valve. If the temperature is higher than this temperature, The second step of quantitative diagnosis. Through a large number of numerical simulation calculation of the temperature field distribution of the drain pipe in thermal power plant under different valve leakage conditions, the wall temperature and leakage volume of the drain pipe, the inner diameter of the pipeline are obtained. Based on the relationship between the thickness of insulation layer and other factors, the mathematical modeling method is used to simulate the data obtained by numerical simulation and the quantitative calculation formula is used to realize the quantitative diagnosis of valve leakage.
【學(xué)位授予單位】：長沙理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TM621

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 廖慶斌;王曉東;胡必忠;;液體閥門泄漏檢測裝置的研制及試驗(yàn)研究[J];中國機(jī)械工程;2011年03期

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本文編號(hào)：1606068