本文關(guān)鍵詞：低溫閥門閥蓋頸部溫度場分析與結(jié)構(gòu)設(shè)計　出處：《蘭州理工大學(xué)》2012年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 低溫閥門 長頸閥蓋 密封 溫度場 填料函 有限元分析

【摘要】：隨著我國工業(yè)的大力發(fā)展，石油化工、空氣分離、天然氣、制冷和低溫工程的生產(chǎn)規(guī)模也不斷發(fā)展壯大，對低溫閥門的要求也越來越高。低溫工程的實踐告訴我們，低溫閥門質(zhì)量的優(yōu)劣直接影響著整個低溫工程的進(jìn)展，實踐的教訓(xùn)是很多的，往往因為一個閥門不密封、關(guān)不嚴(yán)或打不開，導(dǎo)致了試驗的失敗或者一次事故，造成大量的人力、物力、財力的浪費(fèi)，從而影響我國低溫工程的發(fā)展。 低溫閥門的用途和普通工業(yè)管道閥門的用途基本上沒有什么區(qū)別，也是用來直接切斷或調(diào)節(jié)低溫液體。低溫閥門是一種在溫度等于或者低于120K的介質(zhì)中工作的閥門，這種溫度的工作介質(zhì)對閥門構(gòu)件的影響可能是持續(xù)的，也可能是短時間的。除了在低溫介質(zhì)下工作外，同樣應(yīng)當(dāng)考慮到低溫閥門還要在周圍環(huán)境溫度下工作，即在295K左右的溫度下工作，在設(shè)計閥門元件時，必須要考慮低溫介質(zhì)溫度和周圍環(huán)境溫度的共同影響。 在低溫裝置中，閥門的工作條件要比普通工業(yè)閥門惡劣得多。由于溫度變化范圍很大，使閥門的密封十分困難，因而必須要提高閥門的密封效果防止發(fā)生泄漏。填料函的密封性是低溫閥門設(shè)計的關(guān)鍵，采用長頸閥蓋結(jié)構(gòu)，其目的就是起到保護(hù)填料函的功能，若該處有泄漏將降低保冷效果，導(dǎo)致液體氣化，這是在低溫狀態(tài)下隨著溫度的降低，填料的彈性逐漸消失，防漏性能隨之下降。由于介質(zhì)滲漏造成填料與閥桿處結(jié)冰，影響閥桿正常操作，同時也會因閥桿上下移動而將填料劃傷，引起嚴(yán)重泄漏。所以低溫閥門必須采用長頸閥蓋結(jié)構(gòu)形式，此外，長頸閥蓋結(jié)構(gòu)還便于纏繞保冷材料，防止冷能損失。 本文以工程中的低溫承插焊截止閥為例，對低溫閥門長頸閥蓋結(jié)構(gòu)進(jìn)行合理的物理模型簡化，建立閥蓋頸部長度與溫度場關(guān)系的數(shù)學(xué)模型。以傳熱學(xué)為理論依據(jù)，，采用分離變量法求出長頸閥蓋溫度場的分布，并以此為依據(jù)推導(dǎo)出閥蓋頸部長度與溫度場的關(guān)系式，得到閥蓋的最小長度，并且滿足閥門設(shè)計標(biāo)準(zhǔn)。課題采用ANSYS有限元分析軟件作為建模和分析平臺對通徑DN25的低溫承插焊截止閥進(jìn)行熱力分析，從而判定所設(shè)計的閥門閥蓋長度是否合理，為工程設(shè)計提供理論參考依據(jù)。
[Abstract]:With the vigorous development of China's oil industry, chemical industry, air separation, natural gas, refrigeration and cryogenic engineering production scale is also growing, the valve on the low temperature requirements are increasingly high. The practice of cryogenic engineering tells us that the low temperature valve directly affect the quality of the progress of the entire Cryogenic Engineering practice lesson many, often because of a valve is not sealed, closed or not open lax, resulting in the failure of the experiment or an accident, causing a lot of manpower, material resources, waste of resources, thus affecting the cryogenic engineering development of our country.
The use of cryogenic valves and industrial pipeline valve basically does not have what difference, is used to cut or adjust the cryogenic liquid. The low temperature valves work in a temperature equal to or less than 120K in the medium of the valve, the working medium of the temperature effect could be sustained on the valve structure, may also be short time. In addition to work in a low temperature medium, also should take into account the cryogenic valve to work at ambient temperature, which work at about 295K temperature, in the design of valve components, must consider the low temperature medium temperature and ambient temperature influence.
In the low-temperature device, the valve's working conditions than ordinary industrial valves much worse. Due to a wide range of temperature, the valve sealing is very difficult, so we must improve the sealing effect of the valve to prevent leakage. The stuffing box sealing is the key to the design of cryogenic valves, valve cover structure with long neck, its purpose is to protect the stuffing, where leakage will reduce the cold effect, causing the liquid gasification, which is under the condition of low temperature with the decrease of temperature, the elastic filler gradually disappear, leak proof performance decreased. Because of the medium valve stem packing leakage caused by ice, affecting the normal operation of the valve stem, but also because the valve stem moves up and down the filler scratches, causing serious leaks. So cryogenic valves must take the long necked valve cover structure, in addition, long necked valve cover structure is easy to wind cold insulation material, prevent cold energy loss Lost.
In this paper the low-temperature socket welding valve for example, low temperature valve on the long necked bonnet to simplify the structure reasonable physical model, a mathematical model of the valve cover neck length and temperature field relationship. Based on the heat transfer theory, the variable separation method is used to calculate the temperature distribution of the long necked valve field, and then according to the relation derived from the valve cover the neck length and temperature field, get the minimum length of the valve cover and the valve to meet the design standards. Research using ANSYS finite element analysis software for modeling and analyzing platform of diameter DN25 low temperature cut-off valve socket welding thermal analysis, to determine the valve cover design length whether it is reasonable, in order to provide theoretical basis for engineering design.

【學(xué)位授予單位】：蘭州理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2012
【分類號】：TH134

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本文編號：1424473