本文選題：高壓液氧儲(chǔ)罐　切入點(diǎn)：低溫液體　出處：《浙江大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：隨著低溫技術(shù)的發(fā)展,低溫液體的應(yīng)用日趨廣泛。與常規(guī)流體相比,低溫液體沸點(diǎn)低,汽化潛熱小,制取成本高。為了能輸送和存儲(chǔ)單相低溫液體,保證輸送管道和低溫儲(chǔ)罐的安全,預(yù)冷過程不可或缺。目前,工程上對預(yù)冷過程的控制主要依賴于操作人員,處于經(jīng)驗(yàn)與半經(jīng)驗(yàn)狀態(tài),缺乏明確的理論指導(dǎo)。為了提高預(yù)冷過程經(jīng)濟(jì)性,對預(yù)冷時(shí)間與預(yù)冷介質(zhì)消耗量控制提出了更高的要求。對預(yù)冷過程進(jìn)行進(jìn)一步研究有助于此類問題的解決。高壓液氧儲(chǔ)罐筒體較厚,使用過程中對安全性能要求高,預(yù)冷方案的制定尤為重要。現(xiàn)有的預(yù)冷研究主要針對常壓薄壁小管徑管路及超大型LNG貨艙,對厚壁高壓低溫儲(chǔ)罐的預(yù)冷研究鮮有報(bào)道。為了能安全、經(jīng)濟(jì)、快速地對高壓液氧儲(chǔ)罐進(jìn)行預(yù)冷,本文主要開展了以下工作:1)從熱力學(xué)基本理論出發(fā),進(jìn)行預(yù)冷時(shí)間及預(yù)冷介質(zhì)消耗量預(yù)測。采用穩(wěn)態(tài)與變熱導(dǎo)率的熱力學(xué)分析方法,建立儲(chǔ)罐預(yù)冷時(shí)間與預(yù)冷介質(zhì)消耗量數(shù)學(xué)模型,推導(dǎo)了儲(chǔ)罐溫度隨時(shí)間的變化關(guān)系,探討進(jìn)口流量與預(yù)冷時(shí)間、介質(zhì)消耗量之間的相互影響。并將不同的計(jì)算方法相結(jié)合,指導(dǎo)選取最佳預(yù)冷流量;2)采用CFD模擬方法,模擬儲(chǔ)罐在預(yù)冷過程中的降溫過程。通過相變模型修正與時(shí)間步長驗(yàn)證,獲得底部進(jìn)液過程中不同進(jìn)口流量下儲(chǔ)罐的溫度、壓力、氣液分布變化,獲得罐內(nèi)氣體及罐壁的冷卻規(guī)律;3)為了縮短預(yù)冷時(shí)間及減小預(yù)冷過程中罐壁因溫差產(chǎn)生的熱應(yīng)力,對儲(chǔ)罐結(jié)構(gòu)進(jìn)行了優(yōu)化。在罐內(nèi)增設(shè)縱向噴孔,可有效改善罐壁因溫差帶來的應(yīng)力集中現(xiàn)象;基于材料低溫特性的壁厚設(shè)計(jì)計(jì)算方法,充分利用材料的低溫物性,可明顯縮短預(yù)冷時(shí)間。上述研究結(jié)果為高壓液氧儲(chǔ)罐的優(yōu)化設(shè)計(jì)提供參考依據(jù)。
[Abstract]:With the development of cryogenic technology, cryogenic liquids are more and more widely used. Compared with conventional fluids, cryogenic liquids have lower boiling point, lower latent heat of vaporization and higher production cost. The process of precooling is indispensable to ensure the safety of the pipeline and the cryogenic tank. At present, the control of the precooling process in engineering mainly depends on the operator and is in the state of experience and semi-experience. In order to improve the economy of precooling process, A higher demand is put forward for the control of precooling time and consumption of precooled medium. Further study on the precooling process is helpful to solve this problem. The cylinder of high pressure liquid oxygen storage tank is thicker, and the safety performance is high in the process of operation. It is very important to make the precooling scheme. The existing research on precooling is mainly aimed at the small diameter pipe and the super large LNG cargo tank under atmospheric pressure. The research on the precooling of the thick-walled high-pressure low-temperature storage tank is seldom reported. In order to be safe and economical, the research on the pre-cooling of the high-pressure low-temperature storage tank with thick wall is seldom reported. The precooling of high pressure liquid oxygen storage tank is carried out quickly. The following work is mainly carried out in this paper: (1) based on the basic theory of thermodynamics, the precooling time and the consumption of precooled medium are predicted. The thermodynamic analysis method of steady state and variable thermal conductivity is adopted. A mathematical model of precooling time and consumption of precooled medium is established. The relationship between the temperature of storage tank and time is deduced. The interaction between inlet flow rate, precooling time and medium consumption is discussed, and different calculation methods are combined. Using CFD simulation method to simulate the cooling process of the tank during the precooling process, the temperature and pressure of the tank under different inlet flow rates are obtained through phase transformation model correction and time step verification. In order to shorten the precooling time and reduce the thermal stress caused by temperature difference in the tank wall during precooling, the structure of the tank is optimized. It can effectively improve the stress concentration caused by the temperature difference of the tank wall, and make full use of the low temperature physical property of the material by the design and calculation method of the wall thickness based on the low temperature characteristic of the material. The results can provide reference for the optimization design of high pressure liquid oxygen storage tank.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TQ116.14

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本文編號：1637775