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  本文選題：噴射器 + CFD模擬��； 參考：《大連理工大學(xué)》2014年碩士論文

【摘要】：中國已成為世界能源消耗大國,開發(fā)先進(jìn)的能源利用技術(shù)是我國社會經(jīng)濟(jì)發(fā)展的重要課題。噴射式熱泵和噴射式制冷的原理相同,是利用低品位熱源、提高能源利用率的兩種方式。本文研究的噴射器是這兩種系統(tǒng)的重要組成部分。噴射器結(jié)構(gòu)簡單、無運(yùn)動部件、維護(hù)成本低、性能可靠、工質(zhì)范圍廣。唯一的缺點(diǎn)是效率相較壓縮式熱泵和壓縮制冷機(jī)偏低。使用CFD軟件Fluent模擬噴射器內(nèi)部工質(zhì)的流動過程,提高噴射器的制冷和制熱效率,最小化操作成本,是本文研究的主要問題。 本文主要研究工作為： (1)根據(jù)氣體動力學(xué)設(shè)計理論,對廣西某造紙廠熱泵系統(tǒng)中的噴射器進(jìn)行結(jié)構(gòu)設(shè)計。一維傳統(tǒng)理論無法分析噴射器內(nèi)部詳細(xì)流場,本文利用CFD模擬軟件Fluent的優(yōu)點(diǎn),模擬噴射器內(nèi)部流場分布,通過改變噴射器的操作參數(shù)和幾何參數(shù),探究制約噴射器性能的主要因素。 (2)與傳統(tǒng)噴射器結(jié)構(gòu)的改進(jìn)方法相比,改型噴嘴噴射器具有改動小,成本低,不同增強(qiáng)結(jié)構(gòu)易于更換,可應(yīng)用于小型噴射器等優(yōu)點(diǎn),在工業(yè)生產(chǎn)中應(yīng)用前景光明。本文以某廠的蒸汽噴射式熱泵為例,對噴射器噴嘴進(jìn)行改進(jìn),效果顯著。分析了采用后緣增強(qiáng)型噴嘴的噴射器流場結(jié)構(gòu),并對增強(qiáng)噴嘴提高噴射器性能的原理進(jìn)行了討論。 (3)在噴射式制冷系統(tǒng)中,噴射器的性能除了受幾何構(gòu)造和工作條件的影響外,還受制冷劑的制約。本文引入制冷劑的實(shí)際物性,使用CFD技術(shù)數(shù)值模擬了噴射器內(nèi)流場分布和制冷系統(tǒng)的性能,模擬結(jié)果與實(shí)驗(yàn)結(jié)果的誤差低于5%,并在此基礎(chǔ)上研究了沸點(diǎn)相近的綠色環(huán)保型制冷劑R245ca、R245fa和R236ea的噴射制冷性能。模擬結(jié)果表明,R245ca、R245fa和R236ea可作為R123的合適替代制冷劑。
[Abstract]:China has become a major energy consuming country in the world, and developing advanced energy utilization technology is an important subject in China's social and economic development. The principle of jet heat pump is the same as that of jet refrigeration. It is two ways to improve energy efficiency by using low grade heat source. The ejector studied in this paper is an important part of these two systems. The ejector has simple structure, no moving parts, low maintenance cost, reliable performance and wide range of working fluids. The only drawback is that the efficiency is lower than that of compression heat pumps and compression refrigerators. Using CFD software fluent to simulate the flow process of the working fluid in the ejector, to improve the efficiency of cooling and heating of the ejector, and to minimize the operating cost are the main problems studied in this paper. The main work of this paper is as follows: (1) according to the theory of gas dynamic design, the ejector in the heat pump system of a paper mill in Guangxi is designed. The traditional one-dimensional theory can not analyze the detailed flow field inside the ejector. This paper uses the advantage of CFD simulation software fluent to simulate the flow field distribution in the ejector by changing the operating and geometric parameters of the ejector. The main factors that restrict the performance of the injector are explored. (2) compared with the traditional method of improving the structure of the injector, the modified nozzle injector has the advantages of small modification, low cost, easy replacement of different reinforced structures, and can be applied to small injectors, etc. There are bright prospects for application in industrial production. In this paper, the steam jet heat pump in a factory is taken as an example to improve the injector nozzle, and the effect is remarkable. The flow field structure of ejector with rear edge enhanced nozzle is analyzed, and the principle of enhancing nozzle to improve the performance of ejector is discussed. (3) in the ejector refrigeration system, The performance of ejector is not only affected by geometry and working conditions, but also restricted by refrigerant. In this paper, the actual physical properties of the refrigerant are introduced, and the flow field distribution in the ejector and the performance of the refrigeration system are numerically simulated by CFD technique. The error between the simulation results and the experimental results is less than 5. On this basis, the ejection refrigeration performance of the green environmental refrigerants R245CaN R245fa and R236ea with similar boiling points are studied. The simulation results show that R245CaN R245fa and R236ea can be used as suitable alternative refrigerants for R123.
【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TB657

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