發(fā)布時(shí)間：2018-05-17 20:53

  本文選題：二維八邊形液艙 + 比尺效應(yīng)　； 參考：《大連理工大學(xué)》2015年碩士論文

【摘要】：隨著人類將油氣資源開采的目光由陸地轉(zhuǎn)向海洋,浮式液化天然氣平臺(tái)(FLNG)成了世界各國競(jìng)爭(zhēng)的一個(gè)新型裝備制高點(diǎn)。但其運(yùn)營(yíng)過程中儲(chǔ)液艙內(nèi)部存在嚴(yán)重的流體晃蕩沖擊問題,所以,一直都是海洋工程領(lǐng)域的研究熱點(diǎn)。目前,室內(nèi)模型實(shí)驗(yàn)是研究?jī)?chǔ)液艙晃蕩的重要手段。其相對(duì)于理論方法和數(shù)值方法而言,可以得到更加有效的結(jié)果來指導(dǎo)工程實(shí)際。但通過人們開展大量的晃蕩模型實(shí)驗(yàn)研究發(fā)現(xiàn),在實(shí)驗(yàn)過程中將不同比尺模型液艙得到的結(jié)果還原到原型時(shí),會(huì)與原型實(shí)測(cè)結(jié)果之間存在不同程度的偏差,即比尺效應(yīng)。鑒于此,本文通過調(diào)研國內(nèi)外研究進(jìn)展,系統(tǒng)總結(jié)了晃蕩比尺效應(yīng)的實(shí)驗(yàn)研究方法；針對(duì)海洋油氣儲(chǔ)運(yùn)裝備中經(jīng)常采用的GTT薄膜型儲(chǔ)艙,構(gòu)建三個(gè)不同比尺的二維八邊形液艙,并在室內(nèi)開展了三個(gè)液艙之間的晃蕩沖擊比尺效應(yīng)實(shí)驗(yàn)研究。研究給出了詳細(xì)的分析流程,并建立了完善的室內(nèi)半物理仿真實(shí)驗(yàn)平臺(tái)。在實(shí)驗(yàn)開始前,通過幾何相似和弗勞德相似對(duì)運(yùn)動(dòng)激勵(lì)、模型液艙、傳感器布置位置和實(shí)驗(yàn)時(shí)間等主要影響因素均進(jìn)行相似縮比。實(shí)驗(yàn)所得晃蕩荷載結(jié)果還原同樣依據(jù)弗勞德相似實(shí)現(xiàn),特別是在長(zhǎng)時(shí)間激勵(lì)作用下,實(shí)驗(yàn)引入了數(shù)理統(tǒng)計(jì)方法來處理晃蕩沖擊壓力峰值,并從三個(gè)比尺液艙同一位置的壓力峰值超越概率分布研究了模型實(shí)驗(yàn)與原型實(shí)驗(yàn)之間的比尺效應(yīng)。此次研究以20%低載液率和80%高載液率作為兩個(gè)典型的載液工況,開展了三個(gè)比尺液艙在自由液面共振頻率下,分別受到單次橫蕩沖擊激勵(lì)、長(zhǎng)時(shí)間橫蕩和橫搖規(guī)則激勵(lì)作用下的晃蕩沖擊比尺實(shí)驗(yàn)。本文通過對(duì)比分析三個(gè)比尺液艙在同一位置晃蕩沖擊壓力峰值的超越概率分布并結(jié)合相應(yīng)的流場(chǎng)形態(tài),研究了晃蕩模型實(shí)驗(yàn)與原型實(shí)驗(yàn)之間的比尺效應(yīng)。研究結(jié)果表明：在模型與原型液艙內(nèi)同一位置都出現(xiàn)氣體截留現(xiàn)象時(shí),將模型實(shí)驗(yàn)在該位置得到的晃蕩荷載根據(jù)弗勞德相似還原到原型后,與原型實(shí)驗(yàn)對(duì)應(yīng)位置的結(jié)果偏差較大；當(dāng)以上兩種液艙內(nèi)同一位置都受到氣液混合流體沖擊時(shí),模型實(shí)驗(yàn)還原結(jié)果與原型實(shí)驗(yàn)實(shí)測(cè)結(jié)果之間的偏差會(huì)有所減小；只有當(dāng)二者都受到不可壓縮純液體沖擊時(shí),由模型實(shí)驗(yàn)還原后的晃蕩沖擊壓力結(jié)果才能相對(duì)真實(shí)地反映原型實(shí)驗(yàn)實(shí)測(cè)結(jié)果；考慮到原型液艙晃蕩過程中許多特殊的物理現(xiàn)象在小比尺模型液艙內(nèi)無法重現(xiàn),因此,應(yīng)盡可能開展大比尺模型實(shí)驗(yàn)來研究和評(píng)估原型液艙內(nèi)的晃蕩沖擊機(jī)理。
[Abstract]:With the development of oil and gas resources from land to sea, floating liquefied natural gas platform (FLNGG) has become a new type of equipment in the world. However, there is a serious fluid sloshing impact problem in the tank, so it is always a hot topic in the field of ocean engineering. At present, indoor model experiment is an important means to study sloshing of tank. Compared with the theoretical method and numerical method, more effective results can be obtained to guide the engineering practice. However, through a large number of experiments on sloshing model, it is found that when the results obtained from different scale models are reduced to the prototype, there is a different degree of deviation between the experimental results and the measured results, that is, the scale effect. In view of this, through the research progress at home and abroad, this paper systematically summarizes the experimental research methods of sloshing scale effect, constructs three 2-D octagonal liquid tanks with different scales, aiming at the GTT thin film tank, which is often used in offshore oil and gas storage and transportation equipment. An experimental study of sloshing impact scale effect between three tanks was carried out indoors. The detailed analysis flow is given, and a perfect indoor semi-physical simulation experiment platform is established. Before the experiment, the geometric similarity and Froude similarity are used to simulate the main factors such as motion excitation, model tank, sensor position and experimental time. The reduction of the experimental results of sloshing load is also based on the Froude similarity, especially under the long-time excitation, the mathematical statistical method is introduced to deal with the peak value of the sloshing shock pressure. The scale effect between the model experiment and the prototype experiment is studied from the probability distribution of the pressure peak surpassing at the same position in the three scale tanks. In this study, 20% low load liquid rate and 80% high load liquid rate were used as two typical liquid loading conditions, and three scale tanks were subjected to a single wave shock at the resonance frequency of free liquid level, respectively. The scale experiment of sloshing impact under the action of long time rolling and rolling regular excitation. In this paper, the scale effect between the sloshing model experiment and the prototype experiment is studied by comparing and analyzing the probability distribution of the peak value of sloshing impact pressure of three scale tanks at the same position and combining with the corresponding flow pattern. The results show that when the gas interception occurs in the same position of the model and the prototype tank, the sloshing load obtained from the model experiment at this position is reduced to the prototype according to the Froude similarity. The deviation between the results of the model experiment and the prototype experiment will be reduced when the same position of the above two tanks is impacted by the gas-liquid mixed fluid and the results of the reduction of the model experiment and the measured results of the prototype experiment will be reduced. Only when both of them are impacted by incompressible pure liquid can the results of sloshing shock pressure after reduction from the model experiment reflect the measured results of the prototype experiment relatively. Considering that many special physical phenomena in the prototype tank sloshing can not be reproduced in the small scale model tank, large scale model experiments should be carried out as far as possible to study and evaluate the sloshing impact mechanism in the prototype tank.
【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TE97

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本文編號(hào)：1902826